{"gene":"WRN","run_date":"2026-06-11T09:02:06","timeline":{"discoveries":[{"year":1999,"finding":"WRN helicase physically interacts with human replication protein A (hRPA) via co-immunoprecipitation of purified proteins, and hRPA specifically stimulates WRN helicase to unwind long duplex DNA substrates (up to 849 bp); E. coli SSB and T4 gp32 failed to substitute for hRPA, indicating a specific functional interaction.","method":"Co-immunoprecipitation of purified proteins; in vitro helicase assay on long duplex substrates with various SSB proteins","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro helicase reconstitution with purified proteins plus direct co-IP physical interaction, replicated in subsequent studies","pmids":["10373438"],"is_preprint":false},{"year":2000,"finding":"WRN promotes ATP-dependent translocation of Holliday junctions in vitro and, upon S-phase arrest with hydroxyurea, co-localizes with RPA in discrete nuclear foci, consistent with a role in preventing aberrant recombination at stalled replication forks.","method":"In vitro Holliday junction migration assay; immunofluorescence co-localization in hydroxyurea-arrested cells","journal":"EMBO reports","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — in vitro enzymatic reconstitution plus direct cellular localization experiment, two orthogonal methods","pmids":["11256630"],"is_preprint":false},{"year":2002,"finding":"WRN helicase disrupts D-loop structures and its 3′→5′ exonuclease attacks the 3′ end of the inserted strand of D-loops in vitro, implicating WRN in recombination and telomere maintenance pathways that utilize D-loop intermediates.","method":"In vitro biochemical assay with model D-loop DNA substrates; helicase and exonuclease activity measurements","journal":"Biochemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution with defined substrates, two catalytic activities measured on same substrate","pmids":["12427008"],"is_preprint":false},{"year":2002,"finding":"WRN stimulates FEN-1 cleavage efficiency (rather than DNA substrate binding) on flap substrates including Okazaki fragment-processing intermediates, by a mechanism distinct from PCNA-FEN-1 stimulation; WRN does not require a free upstream end to stimulate FEN-1.","method":"In vitro FEN-1 cleavage kinetic assay with streptavidin-blocked substrates; biochemical characterization of WRN-FEN-1 interaction","journal":"Biochemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution with kinetic analysis and mechanistic controls, single lab with multiple substrate variants","pmids":["12356323"],"is_preprint":false},{"year":2002,"finding":"WRN helicase accelerates rRNA transcription as part of an RNA polymerase I (RPI)-associated complex; WRN co-immunoprecipitates with RPA40 (an RPI subunit), WS fibroblasts show reduced rRNA transcription restored by wild-type WRN but not by a nucleolus-targeting-deficient WRN mutant.","method":"Co-immunoprecipitation; rRNA transcription assay in WS cells; complementation with wild-type vs. nucleolus-localization-deficient WRN","journal":"Oncogene","confidence":"High","confidence_rationale":"Tier 2 / Moderate — reciprocal co-IP plus functional complementation with localization mutant, two orthogonal approaches","pmids":["11971179"],"is_preprint":false},{"year":2003,"finding":"WRN plays a structural (non-enzymatic) role in optimizing DNA repair: an exonuclease/helicase double-mutant complements NHEJ and HR deficiencies in WRN-null cells nearly as well as wild-type WRN, whereas single enzymatic mutants show partial complementation, indicating WRN's structural role is separable from its catalytic activities.","method":"Complementation assay in WRN-/- cells with enzymatic-dead WRN mutants; NHEJ and HR repair assays","journal":"Aging cell","confidence":"High","confidence_rationale":"Tier 2 / Moderate — epistasis via structure–function mutagenesis in isogenic cells, multiple repair pathway readouts","pmids":["12934712"],"is_preprint":false},{"year":2003,"finding":"WRN physically and functionally interacts with the homologous recombination mediator RAD52: FRET shows WRN-RAD52 complex formation in vivo at arrested replication fork foci; RAD52 modulates WRN helicase activity in a DNA-structure-dependent manner, and WRN enhances RAD52-mediated strand annealing.","method":"FRET in vivo; co-localization at stalled replication forks; in vitro helicase and strand annealing assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — FRET plus in vitro functional reconstitution, two orthogonal methods in one study","pmids":["12750383"],"is_preprint":false},{"year":2004,"finding":"TRF2 physically interacts with WRN independently of DNA and recruits WRN exonuclease to telomeric DNA substrates: TRF2 binds telomeric-repeat-containing substrates and specifically stimulates WRN exonuclease (not helicase) activity on them.","method":"Direct protein-protein interaction assay (pulldown without DNA); in vitro WRN exonuclease assay on telomeric substrates with/without TRF2","journal":"Oncogene","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — in vitro biochemical reconstitution plus protein interaction assay, two orthogonal methods","pmids":["14712220"],"is_preprint":false},{"year":2004,"finding":"APE1 inhibits WRN helicase activity on single-strand break BER intermediates (likely by occupying the AP site), and this inhibition is relieved by DNA polymerase beta (pol β), suggesting a pol β-mediated handoff of WRN during base excision repair.","method":"In vitro helicase assay on BER intermediate substrates; addition of APE1 and pol β proteins","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — in vitro reconstitution, single lab, single method series","pmids":["15385537"],"is_preprint":false},{"year":2005,"finding":"POT1 strongly stimulates WRN and BLM to unwind long telomeric forked duplexes and D-loop structures in a telomeric-sequence-dependent manner; POT1 binds directly to WRN and BLM in vitro, and full-length POT1 co-precipitates more WRN than BLM from HeLa nuclear extracts.","method":"In vitro helicase unwinding assay on telomeric substrates; pulldown and co-immunoprecipitation from nuclear extracts","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — in vitro reconstitution on defined substrates plus reciprocal protein interaction assays, two orthogonal methods","pmids":["16030011"],"is_preprint":false},{"year":2005,"finding":"Both WRN and BLM bind the extreme C-terminal 18-amino-acid tail of FEN-1, a site adjacent to (but distinct from) the PCNA-binding site; WRN facilitates FEN-1 binding to its preferred double-flap substrate through this protein interaction, and WRN and PCNA have additive stimulatory effects on FEN-1 activity.","method":"Interaction mapping with FEN-1 deletion mutants; functional stimulation assays with WRN + FEN-1 mutants; binding assays","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — domain mapping with deletion mutants plus in vitro functional assays, two orthogonal methods","pmids":["16326861"],"is_preprint":false},{"year":2005,"finding":"WRN helicase is inhibited by p53 both in the presence of RPA (on 849-bp M13 substrates) and in the absence of RPA (on short forked duplexes); WRN, RPA, and p53 co-immunoprecipitate in vivo, and p53 inhibits WRN via a binding site on the WRN helicase domain.","method":"Co-immunoprecipitation in vivo; in vitro helicase assay with purified WRN, RPA, p53; WRN helicase-domain fragment lacking p53-binding site as control","journal":"Cancer research","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — in vitro reconstitution with domain-fragment controls plus in vivo co-IP, two orthogonal methods","pmids":["15735006"],"is_preprint":false},{"year":2005,"finding":"The Pso4 mRNA splicing complex (Pso4/Prp19, Cdc5L, Plrg1, Spf27) is required for ICL processing in vitro, physically associates with WRN through a direct WRN–Cdc5L interaction, and WRN helicase (but not exonuclease) activity is required for ICL processing.","method":"In vitro ICL processing biochemical assay; co-immunoprecipitation; direct binding assay between WRN and Cdc5L; WRN helicase- and exonuclease-mutant analysis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — in vitro reconstitution of ICL processing plus direct protein binding and domain-mutant dissection, multiple orthogonal methods","pmids":["16223718"],"is_preprint":false},{"year":2006,"finding":"Crystal structures of the WRN exonuclease domain reveal a two-metal-ion nuclease mechanism; active-site mutations inactivate the exonuclease; Ku70/80 specifically stimulates WRN exonuclease activity; structure-based WRN-exo mutants alter DNA end joining in human cells. WRN-exo shares structural and mechanistic homology with DnaQ-family replicative proofreading exonucleases.","method":"X-ray crystallography (metal-ion complex structures); active-site mutagenesis + in vitro exonuclease assay; Ku70/80 stimulation assay; DNA end-joining assay in human cells with WRN-exo mutants","journal":"Nature structural & molecular biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure plus active-site mutagenesis plus in vitro biochemistry plus cellular assay, multiple orthogonal methods in one study","pmids":["16622405"],"is_preprint":false},{"year":2007,"finding":"WRN catalyzes ATP-dependent replication fork regression and Holliday junction formation in vitro; this is enhanced on forks with single-stranded gaps (≥11–13 nt) on the leading arm, and WRN exonuclease activity promotes regression by digesting the leading daughter strand to create an optimal substrate.","method":"In vitro fork regression assay with model replication fork substrates; ATP-dependence assay; comparison of wild-type vs. exonuclease-deficient WRN","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution with defined substrates, mechanistic dissection of exonuclease contribution, multiple substrate variants","pmids":["17717003"],"is_preprint":false},{"year":2008,"finding":"SIRT1 interacts with WRN in vitro and in vivo (interaction enhanced after DNA damage); WRN is acetylated by CBP/p300; SIRT1 deacetylates WRN in vitro and in vivo; WRN acetylation decreases its helicase and exonuclease activities; SIRT1-mediated deacetylation reverses this; acetylation alters WRN nuclear distribution and SIRT1 knockdown reduces WRN translocation from nucleoplasm to nucleoli after DNA damage.","method":"Co-immunoprecipitation in vitro and in vivo; acetylation/deacetylation assays; in vitro helicase/exonuclease activity assays on acetylated vs. unacetylated WRN; immunofluorescence for nuclear distribution","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — multiple orthogonal methods (co-IP, in vitro enzymatic assays, localization), independently validated across different experimental approaches","pmids":["18203716"],"is_preprint":false},{"year":2008,"finding":"DNA ligase IIIα and WRN form a complex recruited to DSBs in CML cells; knockdown of either protein increases accumulation of unrepaired DSBs; WRN is up-regulated in BCR-ABL-positive CML cells where it participates in an alternative NHEJ pathway.","method":"Co-immunoprecipitation; siRNA knockdown with γ-H2AX DSB accumulation readout; recruitment to DSB foci","journal":"Blood","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP plus knockdown with functional DSB readout, two orthogonal methods, single lab","pmids":["18524993"],"is_preprint":false},{"year":2008,"finding":"p300 acetylates WRN, stimulating its catalytic activities in vitro and in vivo; acetylated WRN enhances pol β-mediated strand displacement synthesis more than unacetylated WRN; sodium butyrate (HDAC inhibitor) stimulates long-patch BER in wild-type but not WRN-depleted cells, placing acetylated WRN in the long-patch BER pathway.","method":"In vitro acetylation and helicase/exonuclease activity assays; strand displacement synthesis assay; cellular BER assay with HDAC inhibitor and WRN depletion","journal":"PloS one","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — in vitro biochemical reconstitution plus cellular epistasis assay, two orthogonal methods","pmids":["18398454"],"is_preprint":false},{"year":2008,"finding":"WRN is required for ATM pathway activation in response to psoralen ICL-induced DSBs: WRN depletion impairs the intra-S checkpoint, reduces ATM activation and downstream phosphorylation of ATM targets, and increases γ-H2AX levels, indicating WRN facilitates ATM activation at collapsed replication forks.","method":"RNAi knockdown of WRN; immunoblot for ATM and ATM-target phosphorylation; S-phase checkpoint (BrdU incorporation); γ-H2AX measurement","journal":"Molecular biology of the cell","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA epistasis with multiple downstream phosphorylation readouts, single lab","pmids":["18596239"],"is_preprint":false},{"year":2008,"finding":"WRN controls formation of extrachromosomal telomeric circles: WRN helicase is required for TRF2ΔB-mediated telomere shortening via t-loop homologous recombination; both WRN exonuclease and helicase activities are required to suppress spontaneous telomeric circle formation in telomerase-positive WS fibroblasts.","method":"Complementation of WS cells with wild-type vs. exonuclease- or helicase-dead WRN mutants; telomeric circle assay; telomere length analysis","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Moderate — structure-function mutagenesis with two catalytic domain mutants plus quantitative telomeric circle assay, single lab","pmids":["18212065"],"is_preprint":false},{"year":2009,"finding":"WRN is required to repair abnormal replication structures caused by c-Myc-driven S-phase acceleration; depletion of WRN in c-Myc-overexpressing primary human fibroblasts increases DNA damage specifically at replication foci, activating an ATR–CHK1–CHK2–p53 'replication stress' pathway leading to senescence.","method":"WRN siRNA depletion in c-Myc-overexpressing fibroblasts; γ-H2AX co-staining with BrdU; pathway inhibitor analysis; p53 rescue experiment","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — knockdown with defined cellular phenotype and pathway placement via rescue experiment, single lab","pmids":["19554081"],"is_preprint":false},{"year":2010,"finding":"ATR directly phosphorylates WRN at multiple C-terminal S/TQ residues; loss of ATR-mediated phosphorylation prevents WRN accumulation in nuclear foci and co-localization with RPA, causing breakage of stalled forks; ATM kinase phosphorylation of WRN is required for RAD51 recruitment and replication recovery after fork collapse.","method":"Expression of ATR/ATM-unphosphorylatable WRN alleles; immunofluorescence for WRN foci and RPA co-localization; DNA fiber assay; RAD51 recruitment assay; in vitro kinase assay","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — in vitro kinase assay plus structure-function allele analysis with multiple cellular readouts, single lab with multiple methods","pmids":["20802463"],"is_preprint":false},{"year":2010,"finding":"BCR-ABL induces WRN tyrosine phosphorylation (through direct complex formation with WRN) and stimulates WRN helicase and exonuclease activities; activated WRN protects BCR-ABL-positive cells from oxidative/genotoxic stress and promotes unfaithful HR and SSA recombination repair.","method":"Co-immunoprecipitation of WRN-BCR/ABL complex; tyrosine phosphorylation assay; in vitro helicase/exonuclease activity assays after BCR-ABL stimulation; siRNA knockdown with survival and repair readouts","journal":"Cancer research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP plus in vitro activity assays plus cellular knockdown phenotype, single lab","pmids":["21123451"],"is_preprint":false},{"year":2010,"finding":"WRN interacts with PCNA in the absence of DNA damage; DNA damage induces dissociation of PCNA from WRN in an ATM/NBS1-dependent manner, leading to PCNA ubiquitination required for TLS; WRN participates in translesion synthesis through NBS1-FHA-domain-mediated interaction and NBS1-dependent WRN phosphorylation.","method":"Co-immunoprecipitation; PCNA ubiquitination assay; nuclear focus formation; epistasis with NBS1-FHA domain mutants","journal":"Mechanisms of ageing and development","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP plus ubiquitination assay plus domain-mutant epistasis, single lab","pmids":["20600238"],"is_preprint":false},{"year":2010,"finding":"DHX9 (RNA helicase A) stimulates WRN helicase unwinding of RNA-containing Okazaki fragment-like hybrids and RNA-containing 'chicken-foot' structures in vitro, suggesting cooperative function at replication forks; WRN preferentially unwinds RNA-containing substrates while DHX9 alone fails to unwind Okazaki fragment-like hybrids.","method":"In vitro helicase unwinding assay with synthetic RNA-containing substrates; stimulation experiments with purified DHX9","journal":"Nucleic acids research","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — in vitro reconstitution, single lab, single method","pmids":["20385589"],"is_preprint":false},{"year":2010,"finding":"WRN exonuclease activity is blocked by 3′ obstructive groups (3′-phosphate, 3′-phosphoglycolate, 3′-tyrosyl); WRN degrades 3′-OH substrates non-processively but cannot excise any of these common oxidative damage termini.","method":"In vitro exonuclease activity assay on substrates with defined 3′ blocking lesions; side-by-side comparison with APE1, TREX1, p53","journal":"Mechanisms of ageing and development","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution with chemically defined substrates and comparative controls, single lab","pmids":["17224176"],"is_preprint":false},{"year":2010,"finding":"Acetylation of WRN at 6 specific lysine residues (by CBP/p300) stabilizes WRN protein by inhibiting ubiquitination; SIRT1 deacetylation reverses this stabilization; CBP dramatically increases WRN half-life in a manner abolished by the 6KR (lysine-to-arginine) acetylation-site mutant; WRN is strongly acetylated and stabilized after MMC treatment.","method":"Identification of acetylation sites; 6KR mutant stability assay; ubiquitination assay; half-life measurement with cycloheximide chase; MMC treatment acetylation assay; cell survival of 6KR mutant cells","journal":"PloS one","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — site identification with mutagenesis, ubiquitination assay, half-life measurement, functional cellular readout, multiple orthogonal approaches","pmids":["20428248"],"is_preprint":false},{"year":2011,"finding":"XPG interacts directly with WRN through their C-terminal domains and co-localizes with WRN in S-phase nuclear foci at stalled replication forks; the XPG C-terminal domain strongly stimulates WRN helicase activity; XPG itself possesses intrinsic strand annealing activity that cooperates with WRN annealing activity.","method":"Co-immunoprecipitation; domain-mapping with C-terminal deletion mutants; in vitro helicase stimulation assay; in vitro strand annealing assay; immunofluorescence co-localization","journal":"Cell cycle (Georgetown, Tex.)","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — direct interaction mapping plus in vitro helicase stimulation and annealing assays plus cellular co-localization, multiple orthogonal methods","pmids":["21558802"],"is_preprint":false},{"year":2014,"finding":"WRN acts epistatically with DNA2 to promote long-range 5′-to-3′ DNA end resection at DSBs in human cells; WRN and DNA2 interact physically and coordinate enzymatic activities to mediate 5′-to-3′ resection in vitro in an RPA-dependent manner; CDK1-mediated phosphorylation of WRN at S1133 is required for interaction with the MRE11 complex to promote DNA2-dependent resection.","method":"Epistasis analysis by siRNA co-depletion (resection assay); co-immunoprecipitation of WRN-DNA2; in vitro resection assay with purified proteins; DNA fiber analysis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — in vitro biochemical reconstitution plus in vivo epistasis plus physical interaction, replicated across multiple orthogonal approaches","pmids":["25122754"],"is_preprint":false},{"year":2014,"finding":"WRN has a nonenzymatic function in preserving nascent DNA strands at replication-associated DSBs: the NBS1 FHA domain recruits WRN to replication-associated DSBs where WRN stabilizes RAD51 and limits MRE11 exonuclease activity on nascent strands, independent of WRN's own catalytic activities.","method":"DNA fiber assay for nascent strand length; NBS1-FHA domain interaction mapping; RAD51 focus formation assay; MRE11 inhibitor epistasis; WRN catalytic mutant analysis","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 2 / Moderate — domain-mutant epistasis plus fiber assay plus focus formation, multiple orthogonal methods in one study","pmids":["25456133"],"is_preprint":false},{"year":2014,"finding":"TRF2 specifically stimulates WRN-mediated strand exchange between telomeric substrates (but not non-telomeric substrates); TRF2 basic domain is critical for this stimulation; TRF1 (with similar telomeric DNA binding affinity) has minimal effect; TRF2 is displaced from telomeric DNA by WRN independently of WRN ATPase/helicase activities.","method":"In vitro strand exchange assay with telomeric substrates; domain mutant analysis (TRF2 basic domain); comparison with TRF1; ATPase/helicase mutant WRN controls","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution with defined substrates, multiple domain and catalytic mutant controls","pmids":["24880691"],"is_preprint":false},{"year":2015,"finding":"The WRN exonuclease domain protects nascent strands from MRE11/EXO1-dependent degradation at perturbed replication forks: loss of WRN exonuclease enhances nascent strand degradation by MRE11/EXO1 downstream of RAD51, while loss of WRN helicase reduces exonucleolytic processing and causes genome instability.","method":"DNA fiber assay for nascent strand degradation; WRN exonuclease-specific and helicase-specific mutant analysis in cells; MRE11/EXO1 inhibitor epistasis; RAD51 epistasis","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 2 / Moderate — domain-specific mutagenesis with multiple epistasis experiments and quantitative fiber assay, single lab","pmids":["26275776"],"is_preprint":false},{"year":2016,"finding":"WRN regulates pathway choice between classical NHEJ and alternative NHEJ at DSBs: WRN promotes c-NHEJ via its helicase and exonuclease activities; WRN inhibits alt-NHEJ using non-enzymatic functions by suppressing MRE11/CtIP recruitment and protecting DSBs from 5′ end resection; WRN knockdown combined with TRF2 depletion increases telomere fusions abrogated by CtIP knockdown.","method":"WRN knockdown + enzymatic mutant complementation; end resection assay; MRE11/CtIP recruitment assay at DSBs; telomere fusion assay in mouse embryonic fibroblasts with double knockdown","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 / Moderate — structure-function mutagenesis distinguishing enzymatic vs. non-enzymatic roles, plus epistasis with CtIP, multiple cellular readouts","pmids":["27922005"],"is_preprint":false},{"year":2016,"finding":"CDK1 phosphorylates WRN at serine S1133 at collapsed replication forks; S1133 phosphorylation is required for WRN interaction with the MRE11 complex (but not for WRN focus formation); loss of S1133 phosphorylation prevents DNA2-dependent long-range resection, impairs HR and replication recovery, and licenses NHEJ at collapsed forks in a dominant-negative manner.","method":"In vitro CDK1 kinase assay; phospho-specific antibody; S1133A/D phosphomimetic mutant cells; MRE11 co-IP; DNA fiber and resection assays","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — in vitro kinase assay plus phosphomimetic mutant cellular analysis plus co-IP and resection assays, multiple orthogonal methods","pmids":["27634057"],"is_preprint":false},{"year":2016,"finding":"ATR-mediated phosphorylation of WRN at serine S1141 leads to ubiquitination and proteasomal degradation of WRN; this dynamic interaction regulates WRN's association with perturbed replication forks, suppresses new origin firing, and is critical for RAD51-dependent DSB repair and prevention of chromosome breakage during replication stress.","method":"In vivo S1141 phosphorylation identification; phosphomimetic/phospho-dead mutant analysis; ubiquitination assay; DNA fiber analysis for origin firing; RAD51 focus assay","journal":"Oncotarget","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — site-specific phosphomimetic mutagenesis with ubiquitination assay and multiple cellular readouts, single lab","pmids":["26695548"],"is_preprint":false},{"year":2017,"finding":"WRN helicase reciprocates along the same ssDNA strand during DNA unwinding (rather than dissociating and rebinding or strand-switching), with limited processivity; this reciprocating mechanism was shown on forked, overhanging, and G-quadruplex-containing DNA substrates.","method":"Single-molecule FRET (smFRET) analysis of WRN unwinding mechanism on defined substrates","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — single-molecule reconstitution, single lab, single method","pmids":["28266653"],"is_preprint":false},{"year":2018,"finding":"Multiple RPA molecules convert WRN from a weak, repetitive (few-tens-of-bp) helicase into a 'superhelicase' capable of unidirectional unwinding of >1 kb dsDNA; single-molecule FRET and magnetic tweezers demonstrate that binding of multiple RPAs to WRN fundamentally alters its activity and processivity.","method":"Single-molecule FRET; magnetic tweezers; titration of RPA molecules on WRN helicase activity","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 1 / Moderate — single-molecule reconstitution with two orthogonal biophysical methods, clear mechanistic insight","pmids":["29668972"],"is_preprint":false},{"year":2018,"finding":"HERC2 facilitates RPA association with BLM and WRN helicase complexes through HERC2's HECT E3 ubiquitin ligase activity that ubiquitinates RPA2, enabling RPA release onto ssDNA; HERC2 depletion dissociates RPA from WRN/BLM complexes and increases G-quadruplex DNA formation; epistasis analysis shows HERC2 acts through BLM and WRN for G4 suppression.","method":"Co-immunoprecipitation; CRISPR/Cas9 deletion of HERC2 E3 catalytic site; RPA2 ubiquitination assay; G4 staining; siRNA epistasis (triple depletion); in vitro RPA release assay","journal":"Cancer research","confidence":"High","confidence_rationale":"Tier 2 / Moderate — epistasis by triple depletion plus ubiquitination assay plus in vitro RPA release, multiple orthogonal methods","pmids":["30279242"],"is_preprint":false},{"year":2018,"finding":"MDM2 acts as an E3 ubiquitin ligase for WRN: MDM2 interacts with WRN in vivo and in vitro, induces WRN ubiquitination and degradation; DNA damage causes WRN translocation to the nucleoplasm followed by MDM2-mediated degradation; MDM2-dependent WRN degradation mediates cellular senescence in a p53-independent manner.","method":"Co-immunoprecipitation in vivo and in vitro; ubiquitination assay; WRN protein stability assay; senescence assay with etoposide; ectopic WRN rescue experiment","journal":"Oncogene","confidence":"High","confidence_rationale":"Tier 2 / Moderate — co-IP plus ubiquitination assay plus rescue experiment with multiple endpoints, single lab","pmids":["30532073"],"is_preprint":false},{"year":2019,"finding":"PARP1 protein (but not its enzymatic activity) is required for H2O2- and CEES-induced nucleolar-to-nucleoplasmic translocation of WRN in HeLa cells; CPT-induced WRN translocation is independent of PARP1 protein; gossypol (which disrupts PARP1 protein interactions) abolishes WRN translocation, indicating PARP1-protein interactions mediate this stress-specific shuttling.","method":"Immunofluorescence tracking of WRN nucleolar-nucleoplasmic shuttling; PARP1 siRNA knockdown; PARP enzymatic inhibitors vs. gossypol; comparison across multiple genotoxins","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct localization assay with multiple inhibitor conditions and genetic knockdown, single lab","pmids":["31296950"],"is_preprint":false},{"year":2019,"finding":"WRN helicase activity (but not exonuclease activity) is selectively essential in MSI cancer models in vitro and in vivo; WRN depletion in MSI cells induces DSBs, apoptosis, and cell cycle arrest, but not in microsatellite-stable cells.","method":"CRISPR-Cas9 knockout and RNAi screens; helicase-dead vs. exonuclease-dead WRN complementation; in vivo xenograft models; γ-H2AX/apoptosis/cell cycle readouts","journal":"Nature","confidence":"High","confidence_rationale":"Tier 2 / Strong — large-scale genetic screens confirmed by complementation with catalytic mutants and in vivo xenograft models, multiple labs and methods","pmids":["30971823"],"is_preprint":false},{"year":2020,"finding":"Expanded TA-dinucleotide repeats in MSI cells form non-B DNA secondary structures that stall replication forks, activate ATR, and require unwinding by WRN helicase; in the absence of WRN, expanded TA repeats are cleaved by MUS81 nuclease, causing massive chromosome shattering.","method":"DNA fiber assay for replication fork stalling; ATR activation assay; TA-repeat expansion measurement in MSI cells; MUS81 epistasis (knockout); WRN depletion in isogenic MSI/MSS cells; cytogenetic analysis of chromosome shattering","journal":"Nature","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (fiber assay, ATR activation, MUS81 epistasis, cytogenetics) in MSI model cells, mechanistically rigorous","pmids":["32999459"],"is_preprint":false},{"year":2021,"finding":"WRN helicase ensures efficient restart and limits excessive degradation of stalled replication forks in BRCA2-deficient cancer cells; in vitro, WRN ATPase/helicase restores regressed forks and curtails MRE11 nuclease activity on regressed fork substrates; WRN helicase inhibition traps WRN on chromatin leading to fork stalling, MRE11-dependent nucleolytic degradation, MUS81-dependent DSBs, and elevated NHEJ.","method":"In vitro fork restoration/regression assay with purified WRN; WRN helicase inhibitor treatment in BRCA2-deficient cells; DNA fiber assay; MRE11/MUS81 epistasis; BRCA2-deficient xenograft tumor model","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — in vitro reconstitution plus cellular epistasis with inhibitors plus in vivo xenograft, multiple orthogonal methods","pmids":["34772932"],"is_preprint":false},{"year":2021,"finding":"WRN phosphorylation by CDK2 at serine 426 is critical for DSB repair pathway choice: S426 phosphorylation stabilizes WRN's affinity for RPA and promotes long-range resection required for HR; unphosphorylated WRN shows altered DSB recruitment, reduced RPA interaction, and altered strand annealing and DSB repair activities.","method":"In vitro CDK2 kinase assay; phosphomimetic/phospho-dead S426 mutant cells; RPA co-immunoprecipitation; strand annealing assay; DSB repair pathway assay; laser-induced DSB recruitment","journal":"Aging cell","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — in vitro kinase assay plus phosphomimetic mutant analysis with multiple cellular and biochemical readouts, single lab","pmids":["34612580"],"is_preprint":false},{"year":2022,"finding":"WRN helicase directly unfolds cruciform DNA structures in vitro, preventing cleavage by SLX1-SLX4 structure-specific endonuclease; TA-repeat sequences are particularly prone to form cruciforms; WRN and MMR complex MutLα exhibit synergistic (higher-than-additive) cruciform processing in vitro, suggesting cooperative function.","method":"In vitro cruciform DNA unwinding/processing assay; SLX1-SLX4 cleavage assay; TA-repeat cruciform formation assay; combined WRN + MutLα assay","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro biochemical reconstitution with multiple defined substrates and combinatorial enzyme experiments, single lab","pmids":["36541070"],"is_preprint":false},{"year":2022,"finding":"WRN helicase domain regulates transcriptional expression of SHOX by unwinding G-quadruplex structures in the SHOX promoter region; WRN-null zebrafish exhibit impaired bone growth rescued by SHOX/shox overexpression; chondrogenesis requires WRN and is linked specifically to its helicase domain.","method":"WRN/wrn knockout zebrafish model; SHOX identification as WRN target; G-quadruplex unwinding assay; genetic rescue with SHOX overexpression in WRN-null background; in vitro transcription/promoter assay","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — in vitro G4 unwinding assay plus in vivo genetic rescue in zebrafish, two orthogonal methods","pmids":["36114168"],"is_preprint":false},{"year":2024,"finding":"HRO761, an allosteric WRN helicase inhibitor, binds at the interface of the D1 and D2 helicase domains of WRN, locking it in an inactive conformation; pharmacological inhibition recapitulates WRN-depletion phenotype (DNA damage, selective MSI cell growth inhibition); HRO761 causes WRN degradation in MSI but not MSS cells.","method":"X-ray/cryo structural characterization of HRO761-WRN complex; biochemical helicase inhibition assay; selectivity profiling; cellular DNA damage assay; WRN protein stability assay in MSI vs. MSS cells; in vivo xenograft","journal":"Nature","confidence":"High","confidence_rationale":"Tier 1 / Strong — structural characterization plus biochemical assay plus cellular and in vivo validation, multiple orthogonal approaches in one rigorous study","pmids":["38658754"],"is_preprint":false},{"year":2024,"finding":"VVD-133214, a covalent allosteric WRN inhibitor, selectively engages cysteine C727 in the helicase domain at a region subject to interdomain movement during DNA unwinding; binding is cooperative with nucleotide and stabilizes compact conformations lacking dynamic flexibility for helicase function, causing DSBs and cell death selectively in MSI-H cells.","method":"Chemoproteomics identification of C727; covalent binding characterization; nucleotide cooperativity assay; conformational studies; selective cellular toxicity in MSI-H vs. MSS cells; in vivo xenograft models","journal":"Nature","confidence":"High","confidence_rationale":"Tier 1 / Strong — chemoproteomics site identification plus covalent mechanism characterization plus in vivo validation, multiple orthogonal methods","pmids":["38658751"],"is_preprint":false},{"year":2025,"finding":"WRN (with DNA2) specifically resects the 5′ end of ssDNA gaps through a mechanism distinct from DSB end resection, independent of MRN-CtIP; this 5′-gap resection by DNA2-WRN/BLM alters ssDNA gap repair kinetics and, in BRCA1-deficient cells, excessive resection leads to larger gaps causing DNA breaks in subsequent cell cycles.","method":"Single-molecule DNA fiber analysis; electron microscopy; biochemical resection assays with purified proteins; epistasis with MRN-CtIP knockdown; BRCA1-deficient cell analysis","journal":"Genes & development","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — in vitro biochemical reconstitution plus EM plus fiber analysis plus genetic epistasis, multiple orthogonal methods","pmids":["40127955"],"is_preprint":false}],"current_model":"WRN is a multifunctional RecQ DNA helicase/exonuclease whose core activities (3′→5′ helicase, 3′→5′ exonuclease, strand annealing, and fork regression) are directed to stalled/collapsed replication forks, Holliday junctions, D-loops, cruciform structures, and telomeric substrates; its helicase activity is stimulated by RPA (which converts WRN into a superhelicase capable of unwinding >1 kb), POT1, TRF2, XPG, RECQL5, and DHX9, while its exonuclease is recruited by TRF2 and Ku70/80 to telomeres and DSB ends, respectively; WRN promotes c-NHEJ and CDK1/CDK2-phosphorylation-dependent HR (via DNA2-mediated long-range resection) while suppressing alternative NHEJ through non-enzymatic shielding of DSBs from MRE11/CtIP; post-translational regulation by SIRT1/CBP-p300 acetylation, MDM2/ubiquitin-proteasome degradation, ATR phosphorylation (S1141 for regulated proteasomal turnover), ATM phosphorylation (for RAD51 recruitment), CDK1 phosphorylation (S1133 for MRE11 interaction and DNA2-resection), and CDK2 phosphorylation (S426 for RPA affinity and pathway choice) orchestrate its spatiotemporal deployment; in MSI cancers, WRN helicase is essential to unwind expanded TA-dinucleotide repeat-derived cruciform/non-B structures that would otherwise be cleaved by MUS81, making WRN a synthetic lethal therapeutic target exploited by allosteric covalent inhibitors that lock WRN in an inactive conformation."},"narrative":{"mechanistic_narrative":"WRN is a multifunctional RecQ-family DNA helicase/exonuclease that directs its catalytic activities to stalled and collapsed replication forks, recombination intermediates, and telomeres to preserve genome stability [PMID:11256630, PMID:17717003, PMID:12427008]. Its core 3′→5′ helicase and 3′→5′ exonuclease activities act on Holliday junctions, D-loops, replication forks, cruciforms, and G-quadruplexes, catalyzing ATP-dependent fork regression and strand annealing [PMID:11256630, PMID:12427008, PMID:17717003, PMID:36541070]; single-molecule analyses show WRN unwinds by reciprocating along ssDNA with limited intrinsic processivity, but multiple RPA molecules convert it into a unidirectional 'superhelicase' capable of unwinding >1 kb [PMID:28266653, PMID:29668972]. WRN activity is shaped by an extensive partner network that targets it to specific substrates: RPA and XPG stimulate its helicase at stalled forks [PMID:11256630, PMID:21558802], POT1 and TRF2 stimulate telomeric helicase/exonuclease and strand exchange [PMID:16030011, PMID:14712220, PMID:24880691], Ku70/80 stimulates the exonuclease at DSB ends [PMID:16622405], and p53 inhibits the helicase [PMID:15735006]. At replication forks and DSBs WRN coordinates end resection by acting epistatically with DNA2 to drive long-range 5′→3′ resection for homologous recombination, while also resecting the 5′ ends of ssDNA gaps through a distinct MRN-CtIP-independent route [PMID:25122754, PMID:40127955]; it additionally serves non-enzymatic structural roles, stabilizing RAD51 and shielding nascent strands and DSBs from MRE11/CtIP to promote classical NHEJ and suppress alternative NHEJ [PMID:25456133, PMID:26275776, PMID:27922005]. Deployment is orchestrated by post-translational modification: ATR phosphorylation at S1141 drives ubiquitin-proteasomal turnover [PMID:26695548], ATM phosphorylation enables RAD51 recruitment [PMID:20802463], CDK1 phosphorylation at S1133 licenses MRE11 interaction and DNA2 resection [PMID:27634057], CDK2 phosphorylation at S426 tunes RPA affinity and DSB pathway choice [PMID:34612580], and CBP/p300 acetylation (reversed by SIRT1) regulates activity, localization, and MDM2-dependent stability [PMID:18203716, PMID:20428248, PMID:30532073]. In microsatellite-instable cancers WRN helicase is selectively essential to unwind expanded TA-dinucleotide-repeat cruciform/non-B structures that, absent WRN, are cleaved by MUS81 to cause chromosome shattering, establishing WRN as a synthetic-lethal target now drugged by allosteric covalent helicase inhibitors that lock it in an inactive conformation [PMID:30971823, PMID:32999459, PMID:38658754, PMID:38658751].","teleology":[{"year":1999,"claim":"Established that WRN helicase is not an autonomous enzyme but is functionally coupled to the single-strand binding protein RPA, defining the first key cofactor that enables long-range unwinding.","evidence":"Co-IP of purified proteins and in vitro helicase assays on long duplex substrates comparing RPA to bacterial/phage SSBs","pmids":["10373438"],"confidence":"High","gaps":["Did not resolve stoichiometry or the conformational basis of RPA stimulation","No cellular demonstration of the interaction at forks"]},{"year":2002,"claim":"Defined WRN's substrate repertoire beyond simple duplexes by showing it disrupts D-loops, stimulates FEN-1 flap cleavage, and operates within an RNA polymerase I complex, linking it to recombination, Okazaki processing, and rRNA transcription.","evidence":"In vitro biochemistry on D-loop and flap substrates; co-IP with RPI subunit RPA40 and complementation of WS fibroblasts","pmids":["12427008","12356323","11971179"],"confidence":"High","gaps":["Relative physiological weighting of these activities unresolved","Nucleolar role mechanistically distinct from fork roles"]},{"year":2003,"claim":"Distinguished WRN's catalytic from structural contributions to repair, showing a non-enzymatic scaffolding role in NHEJ/HR optimization separable from helicase/exonuclease activity, and a functional RAD52 interaction at forks.","evidence":"Complementation of WRN-null cells with enzymatic-dead mutants in NHEJ/HR assays; in vivo FRET and in vitro reconstitution with RAD52","pmids":["12934712","12750383"],"confidence":"High","gaps":["Molecular basis of the structural role not defined at this stage","Which DSB substrates require scaffolding vs catalysis unclear"]},{"year":2004,"claim":"Identified telomere- and DSB-specific recruiters that target WRN's exonuclease, showing TRF2 directs WRN to telomeric substrates and Ku70/80 to DNA ends.","evidence":"DNA-independent pulldowns and in vitro exonuclease assays on telomeric substrates (TRF2); later crystallographic work with Ku70/80 stimulation","pmids":["14712220"],"confidence":"High","gaps":["In vivo consequences of TRF2-directed exonuclease not yet established","Selectivity of stimulation for exonuclease over helicase not mechanistically explained"]},{"year":2006,"claim":"Provided the structural and catalytic basis of the WRN exonuclease, defining a two-metal-ion DnaQ-family proofreading mechanism and confirming Ku70/80 stimulation and a role in cellular end joining.","evidence":"X-ray crystallography of metal-ion complexes plus active-site mutagenesis, in vitro exonuclease assays, and DNA end-joining assays in human cells","pmids":["16622405"],"confidence":"High","gaps":["Structure of the helicase domain and full-length enzyme not solved here","How exonuclease and helicase domains are coordinated unresolved"]},{"year":2007,"claim":"Demonstrated WRN catalyzes ATP-dependent replication fork regression with its exonuclease shaping the substrate, mechanistically placing WRN in the protection and remodeling of stalled forks.","evidence":"In vitro fork regression assays on model substrates comparing wild-type and exonuclease-deficient WRN","pmids":["17717003"],"confidence":"High","gaps":["In vivo regulation of fork regression by WRN not addressed","Coordination with other fork-remodeling enzymes unknown"]},{"year":2008,"claim":"Revealed acetylation as a major regulatory layer, with CBP/p300 acetylation tuning WRN activity and localization and SIRT1 reversing it, while also placing WRN in long-patch BER, ATM checkpoint activation, and alt-NHEJ in CML.","evidence":"Acetylation/deacetylation and activity assays; HDAC-inhibitor BER epistasis; RNAi with ATM-target phosphorylation readouts; co-IP with DNA ligase IIIα in CML cells","pmids":["18203716","18398454","18596239","18524993","18212065"],"confidence":"High","gaps":["Causal hierarchy among acetylation, localization, and activity changes incompletely ordered","Context dependence of pro- vs anti-recombinogenic roles unresolved"]},{"year":2009,"claim":"Placed WRN in the cellular response to oncogene-driven replication stress, showing its loss converts c-Myc-accelerated S-phase into ATR–CHK1–p53 signaling and senescence.","evidence":"WRN siRNA in c-Myc-overexpressing fibroblasts with γ-H2AX/BrdU staining and pathway inhibitor and p53 rescue analysis","pmids":["19554081"],"confidence":"Medium","gaps":["Direct DNA substrate engaged under oncogenic stress not defined","Single cell system without biochemical reconstitution"]},{"year":2010,"claim":"Defined the kinase control of WRN's fork localization and stability, with ATR/ATM phosphorylation governing focus formation, RPA co-localization, and RAD51 recruitment, and established further telomeric (POT1) and fork (DHX9) cofactors plus exonuclease limits at oxidative lesions.","evidence":"ATR/ATM-unphosphorylatable alleles with fiber and focus assays; in vitro helicase stimulation by POT1 and DHX9; exonuclease assays on 3′-blocked substrates; PCNA/NBS1 TLS co-IPs","pmids":["20802463","16030011","20385589","17224176","20600238","21123451"],"confidence":"High","gaps":["Site-resolved ATR/ATM target residues not fully mapped at this stage","Integration of multiple kinase inputs not yet unified"]},{"year":2011,"claim":"Identified XPG as a direct C-terminal partner that stimulates WRN helicase and cooperates in strand annealing at stalled forks, expanding the fork-associated WRN interactome.","evidence":"Co-IP, domain mapping, in vitro helicase/annealing assays, and S-phase co-localization","pmids":["21558802"],"confidence":"High","gaps":["Physiological pathway in which WRN-XPG operates not defined in cells","Whether XPG nuclease activity is involved unaddressed"]},{"year":2014,"claim":"Resolved WRN's role in DSB end resection, showing it acts with DNA2 for RPA-dependent long-range resection (with CDK1-phospho-S1133 enabling MRE11 interaction) while also non-enzymatically protecting nascent strands via NBS1 recruitment.","evidence":"siRNA epistasis, WRN-DNA2 co-IP, in vitro resection with purified proteins, DNA fiber assays, NBS1-FHA domain mapping, catalytic-mutant analysis","pmids":["25122754","25456133"],"confidence":"High","gaps":["Switch between resection-promoting and strand-protecting modes not fully defined","Relative contributions of WRN catalysis vs DNA2 unclear in vivo"]},{"year":2015,"claim":"Separated the opposing domain functions at perturbed forks, showing the WRN exonuclease protects nascent strands from MRE11/EXO1 degradation while the helicase enables proper exonucleolytic processing downstream of RAD51.","evidence":"Domain-specific mutant analysis with DNA fiber assays and MRE11/EXO1/RAD51 epistasis","pmids":["26275776"],"confidence":"High","gaps":["How the two domains are temporally coordinated at a single fork unresolved","Regulatory signal selecting protection vs processing not identified"]},{"year":2016,"claim":"Established WRN as an arbiter of DSB pathway choice and detailed the phospho-regulation underlying it, promoting classical NHEJ enzymatically while non-enzymatically suppressing alt-NHEJ, with CDK1-S1133 licensing DNA2 resection and ATR-S1141 driving turnover.","evidence":"Knockdown plus enzymatic-mutant complementation, end-resection and MRE11/CtIP recruitment assays, telomere fusion assays, in vitro CDK1 kinase assay with phosphomimetic mutants and ubiquitination assays","pmids":["27922005","27634057","26695548"],"confidence":"High","gaps":["Integration of CDK1 and ATR inputs into a single decision model incomplete","Cell-cycle timing of pathway switching not fully resolved"]},{"year":2018,"claim":"Mechanistically explained how RPA reprograms WRN and how that loading is regulated, showing multiple RPAs create a >1 kb superhelicase, HERC2-mediated RPA2 ubiquitination enables RPA handoff, and MDM2 ubiquitinates WRN to drive p53-independent senescence.","evidence":"Single-molecule FRET and magnetic tweezers; HERC2 E3-dead CRISPR lines with RPA2 ubiquitination and G4 assays; MDM2 co-IP, ubiquitination, stability, and senescence rescue assays","pmids":["29668972","30279242","30532073"],"confidence":"High","gaps":["How superhelicase behavior is engaged at specific in vivo substrates unresolved","Cross-talk between MDM2 and ATR/acetylation-dependent turnover not unified"]},{"year":2019,"claim":"Identified the dependency that makes WRN a cancer target, showing WRN helicase (not exonuclease) is selectively essential in microsatellite-instable cells where its loss triggers DSBs and death.","evidence":"CRISPR/RNAi screens, helicase- vs exonuclease-dead complementation, and in vivo xenografts with damage/apoptosis readouts","pmids":["30971823"],"confidence":"High","gaps":["Molecular nature of the MSI-specific substrate not defined in this study","Why helicase but not exonuclease is essential left for follow-up"]},{"year":2020,"claim":"Defined the MSI synthetic-lethal mechanism, showing expanded TA-dinucleotide repeats form non-B structures that stall forks and, without WRN unwinding, are cleaved by MUS81 to shatter chromosomes.","evidence":"DNA fiber stalling assays, ATR activation, TA-repeat measurement, MUS81 epistasis, and cytogenetics in isogenic MSI/MSS cells","pmids":["32999459"],"confidence":"High","gaps":["Full spectrum of non-B structures resolved by WRN not enumerated","Whether other nucleases contribute to shattering unaddressed"]},{"year":2021,"claim":"Extended WRN's fork-protective role to BRCA2-deficient contexts and refined resection pathway choice, showing WRN helicase limits MRE11 degradation of regressed forks and CDK2-S426 phosphorylation stabilizes RPA binding to direct HR.","evidence":"In vitro fork restoration assays, helicase-inhibitor treatment with MRE11/MUS81 epistasis and xenografts; in vitro CDK2 kinase assay with S426 phosphomimetic mutants and RPA co-IP","pmids":["34772932","34612580"],"confidence":"High","gaps":["How CDK2-S426 and CDK1-S1133 signals are coordinated unresolved","In vivo therapeutic window in BRCA2-deficient tumors not fully defined"]},{"year":2022,"claim":"Linked WRN's structure-resolving helicase to broader physiology and to anti-nuclease protection, showing it unfolds cruciforms to prevent SLX1-SLX4 cleavage (synergizing with MutLα) and unwinds promoter G-quadruplexes to drive SHOX expression and chondrogenesis.","evidence":"In vitro cruciform/SLX1-SLX4 and combined MutLα assays; WRN-null zebrafish with G4 unwinding assays and SHOX rescue","pmids":["36541070","36114168"],"confidence":"High","gaps":["Generality of transcriptional G4-resolving role across loci unknown","Mechanistic basis of WRN-MutLα synergy not defined"]},{"year":2024,"claim":"Delivered structurally defined allosteric WRN inhibitors, showing HRO761 binds the D1-D2 helicase interface and VVD-133214 covalently engages cysteine C727 to lock WRN inactive and selectively kill MSI-H cells.","evidence":"Structural and chemoproteomic characterization, biochemical helicase inhibition, conformational/nucleotide cooperativity studies, and MSI-selective cellular and xenograft validation","pmids":["38658754","38658751"],"confidence":"High","gaps":["Long-term resistance mechanisms to WRN inhibition not characterized","Differential WRN degradation in MSI vs MSS cells mechanistically incomplete"]},{"year":2025,"claim":"Distinguished WRN's gap-resection activity from DSB resection, showing DNA2-WRN/BLM resects 5′ ends of ssDNA gaps independently of MRN-CtIP and that excessive resection in BRCA1-deficient cells generates damaging gaps.","evidence":"Single-molecule fiber analysis, electron microscopy, in vitro resection with purified proteins, and MRN-CtIP epistasis in BRCA1-deficient cells","pmids":["40127955"],"confidence":"High","gaps":["How gap vs DSB resection modes are selected in cells unresolved","Regulatory inputs controlling the extent of gap resection unknown"]},{"year":null,"claim":"How the full set of post-translational signals (ATR/ATM/CDK1/CDK2 phosphorylation, acetylation, MDM2/HERC2 ubiquitination) is integrated in real time to choose among fork regression, gap resection, DSB resection, NHEJ promotion, and degradation at a given lesion remains unresolved.","evidence":"","pmids":[],"confidence":"High","gaps":["No unified quantitative model linking modification state to substrate choice","Structure of full-length WRN engaging physiological substrates lacking","Lesion-context determinants of enzymatic vs non-enzymatic deployment undefined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140657","term_label":"ATP-dependent activity","supporting_discovery_ids":[0,14,35,36]},{"term_id":"GO:0140097","term_label":"catalytic activity, acting on DNA","supporting_discovery_ids":[2,13,14,28,48]},{"term_id":"GO:0003677","term_label":"DNA binding","supporting_discovery_ids":[1,2,44,45]},{"term_id":"GO:0016787","term_label":"hydrolase activity","supporting_discovery_ids":[13,25,14]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[3,10,29,32]}],"localization":[{"term_id":"GO:0005654","term_label":"nucleoplasm","supporting_discovery_ids":[1,15,39]},{"term_id":"GO:0005730","term_label":"nucleolus","supporting_discovery_ids":[4,15,39]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[1,21]}],"pathway":[{"term_id":"R-HSA-73894","term_label":"DNA Repair","supporting_discovery_ids":[13,28,32,48]},{"term_id":"R-HSA-69306","term_label":"DNA Replication","supporting_discovery_ids":[1,14,31,42]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[40,41,46,47]},{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[4,45]},{"term_id":"R-HSA-8953854","term_label":"Metabolism of RNA","supporting_discovery_ids":[12,24]}],"complexes":["RNA polymerase I complex","Pso4/Prp19 splicing complex"],"partners":["RPA","TRF2","POT1","DNA2","XPG","FEN1","NBS1","MDM2"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q14191","full_name":"Bifunctional 3'-5' exonuclease/ATP-dependent helicase WRN","aliases":["DNA helicase, RecQ-like type 3","RecQ protein-like 2","Werner syndrome protein"],"length_aa":1432,"mass_kda":162.5,"function":"Multifunctional enzyme that has magnesium and ATP-dependent 3'-5' DNA-helicase activity on partially duplex substrates (PubMed:9224595, PubMed:9288107, PubMed:9611231). Also has 3'->5' exonuclease activity towards double-stranded (ds)DNA with a 5'-overhang (PubMed:11863428). Has no nuclease activity towards single-stranded (ss)DNA or blunt-ended dsDNA (PubMed:11863428). Helicase activity is most efficient with (d)ATP, but (d)CTP will substitute with reduced efficiency; strand displacement is enhanced by single-strand binding-protein (heterotrimeric replication protein A complex, RPA1, RPA2, RPA3) (PubMed:9611231). Binds preferentially to DNA substrates containing alternate secondary structures, such as replication forks and Holliday junctions. May play an important role in the dissociation of joint DNA molecules that can arise as products of homologous recombination, at stalled replication forks or during DNA repair. Alleviates stalling of DNA polymerases at the site of DNA lesions. Plays a role in the formation of DNA replication focal centers; stably associates with foci elements generating binding sites for RP-A (By similarity). Plays a role in double-strand break repair after gamma-irradiation (PubMed:9224595, PubMed:9288107, PubMed:9611231). Unwinds some G-quadruplex DNA (d(CGG)n tracts); unwinding seems to occur in both 5'-3' and 3'-5' direction and requires a short single-stranded tail (PubMed:10212265). d(CGG)n tracts have a propensity to assemble into tetraplex structures; other G-rich substrates from a telomeric or IgG switch sequence are not unwound (PubMed:10212265). Depletion leads to chromosomal breaks and genome instability (PubMed:33199508)","subcellular_location":"Nucleus, nucleolus; Nucleus; Nucleus, nucleoplasm; Chromosome","url":"https://www.uniprot.org/uniprotkb/Q14191/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/WRN","classification":"Not Classified","n_dependent_lines":92,"n_total_lines":1208,"dependency_fraction":0.076158940397351},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/WRN","total_profiled":1310},"omim":[{"mim_id":"618041","title":"PURINE-RICH ELEMENT-BINDING PROTEIN G; PURG","url":"https://www.omim.org/entry/618041"},{"mim_id":"616200","title":"RUIJS-AALFS PROGEROID SYNDROME; RJALS","url":"https://www.omim.org/entry/616200"},{"mim_id":"610965","title":"XFE PROGEROID SYNDROME; XFEPS","url":"https://www.omim.org/entry/610965"},{"mim_id":"608196","title":"WERNER HELICASE-INTERACTING PROTEIN 1; WRNIP1","url":"https://www.omim.org/entry/608196"},{"mim_id":"606609","title":"3-PRIME @REPAIR EXONUCLEASE 1; TREX1","url":"https://www.omim.org/entry/606609"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Enhanced","locations":[{"location":"Nuclear speckles","reliability":"Enhanced"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/WRN"},"hgnc":{"alias_symbol":["RECQL2","RECQ3"],"prev_symbol":[]},"alphafold":{"accession":"Q14191","domains":[{"cath_id":"3.30.420.10","chopping":"41-237","consensus_level":"high","plddt":87.4341,"start":41,"end":237},{"cath_id":"3.40.50.300","chopping":"535-728","consensus_level":"high","plddt":88.7035,"start":535,"end":728},{"cath_id":"3.40.50.300","chopping":"736-905","consensus_level":"high","plddt":85.6804,"start":736,"end":905},{"cath_id":"1.10.10.10","chopping":"957-1065","consensus_level":"high","plddt":88.1962,"start":957,"end":1065},{"cath_id":"1.10.150.80","chopping":"1148-1227","consensus_level":"high","plddt":85.3456,"start":1148,"end":1227},{"cath_id":"-","chopping":"1260-1356","consensus_level":"high","plddt":86.1359,"start":1260,"end":1356}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q14191","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q14191-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q14191-F1-predicted_aligned_error_v6.png","plddt_mean":68.62},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=WRN","jax_strain_url":"https://www.jax.org/strain/search?query=WRN"},"sequence":{"accession":"Q14191","fasta_url":"https://rest.uniprot.org/uniprotkb/Q14191.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q14191/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q14191"}},"corpus_meta":[{"pmid":"30971823","id":"PMC_30971823","title":"WRN helicase is a synthetic lethal target in microsatellite unstable cancers.","date":"2019","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/30971823","citation_count":348,"is_preprint":false},{"pmid":"11256630","id":"PMC_11256630","title":"Werner's syndrome protein (WRN) migrates Holliday junctions and co-localizes with RPA upon replication arrest.","date":"2000","source":"EMBO reports","url":"https://pubmed.ncbi.nlm.nih.gov/11256630","citation_count":329,"is_preprint":false},{"pmid":"11138010","id":"PMC_11138010","title":"SGS1, the Saccharomyces cerevisiae homologue of BLM and WRN, suppresses genome instability and homeologous recombination.","date":"2001","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/11138010","citation_count":284,"is_preprint":false},{"pmid":"10373438","id":"PMC_10373438","title":"Functional and physical interaction between WRN helicase and human replication protein A.","date":"1999","source":"The Journal of biological 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development","url":"https://pubmed.ncbi.nlm.nih.gov/40127955","citation_count":19,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":45397,"output_tokens":12499,"usd":0.161838,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":23812,"output_tokens":7204,"usd":0.14958,"stage2_stop_reason":"end_turn"},"total_usd":0.311418,"stage1_batch_id":"msgbatch_01UT1AahFPCAyn2uVweS7A9z","stage2_batch_id":"msgbatch_01HuKWtKNT4Pqj1bc8eEP5RV","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1999,\n      \"finding\": \"WRN helicase physically interacts with human replication protein A (hRPA) via co-immunoprecipitation of purified proteins, and hRPA specifically stimulates WRN helicase to unwind long duplex DNA substrates (up to 849 bp); E. coli SSB and T4 gp32 failed to substitute for hRPA, indicating a specific functional interaction.\",\n      \"method\": \"Co-immunoprecipitation of purified proteins; in vitro helicase assay on long duplex substrates with various SSB proteins\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro helicase reconstitution with purified proteins plus direct co-IP physical interaction, replicated in subsequent studies\",\n      \"pmids\": [\"10373438\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"WRN promotes ATP-dependent translocation of Holliday junctions in vitro and, upon S-phase arrest with hydroxyurea, co-localizes with RPA in discrete nuclear foci, consistent with a role in preventing aberrant recombination at stalled replication forks.\",\n      \"method\": \"In vitro Holliday junction migration assay; immunofluorescence co-localization in hydroxyurea-arrested cells\",\n      \"journal\": \"EMBO reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — in vitro enzymatic reconstitution plus direct cellular localization experiment, two orthogonal methods\",\n      \"pmids\": [\"11256630\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"WRN helicase disrupts D-loop structures and its 3′→5′ exonuclease attacks the 3′ end of the inserted strand of D-loops in vitro, implicating WRN in recombination and telomere maintenance pathways that utilize D-loop intermediates.\",\n      \"method\": \"In vitro biochemical assay with model D-loop DNA substrates; helicase and exonuclease activity measurements\",\n      \"journal\": \"Biochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution with defined substrates, two catalytic activities measured on same substrate\",\n      \"pmids\": [\"12427008\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"WRN stimulates FEN-1 cleavage efficiency (rather than DNA substrate binding) on flap substrates including Okazaki fragment-processing intermediates, by a mechanism distinct from PCNA-FEN-1 stimulation; WRN does not require a free upstream end to stimulate FEN-1.\",\n      \"method\": \"In vitro FEN-1 cleavage kinetic assay with streptavidin-blocked substrates; biochemical characterization of WRN-FEN-1 interaction\",\n      \"journal\": \"Biochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution with kinetic analysis and mechanistic controls, single lab with multiple substrate variants\",\n      \"pmids\": [\"12356323\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"WRN helicase accelerates rRNA transcription as part of an RNA polymerase I (RPI)-associated complex; WRN co-immunoprecipitates with RPA40 (an RPI subunit), WS fibroblasts show reduced rRNA transcription restored by wild-type WRN but not by a nucleolus-targeting-deficient WRN mutant.\",\n      \"method\": \"Co-immunoprecipitation; rRNA transcription assay in WS cells; complementation with wild-type vs. nucleolus-localization-deficient WRN\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal co-IP plus functional complementation with localization mutant, two orthogonal approaches\",\n      \"pmids\": [\"11971179\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"WRN plays a structural (non-enzymatic) role in optimizing DNA repair: an exonuclease/helicase double-mutant complements NHEJ and HR deficiencies in WRN-null cells nearly as well as wild-type WRN, whereas single enzymatic mutants show partial complementation, indicating WRN's structural role is separable from its catalytic activities.\",\n      \"method\": \"Complementation assay in WRN-/- cells with enzymatic-dead WRN mutants; NHEJ and HR repair assays\",\n      \"journal\": \"Aging cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — epistasis via structure–function mutagenesis in isogenic cells, multiple repair pathway readouts\",\n      \"pmids\": [\"12934712\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"WRN physically and functionally interacts with the homologous recombination mediator RAD52: FRET shows WRN-RAD52 complex formation in vivo at arrested replication fork foci; RAD52 modulates WRN helicase activity in a DNA-structure-dependent manner, and WRN enhances RAD52-mediated strand annealing.\",\n      \"method\": \"FRET in vivo; co-localization at stalled replication forks; in vitro helicase and strand annealing assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — FRET plus in vitro functional reconstitution, two orthogonal methods in one study\",\n      \"pmids\": [\"12750383\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"TRF2 physically interacts with WRN independently of DNA and recruits WRN exonuclease to telomeric DNA substrates: TRF2 binds telomeric-repeat-containing substrates and specifically stimulates WRN exonuclease (not helicase) activity on them.\",\n      \"method\": \"Direct protein-protein interaction assay (pulldown without DNA); in vitro WRN exonuclease assay on telomeric substrates with/without TRF2\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — in vitro biochemical reconstitution plus protein interaction assay, two orthogonal methods\",\n      \"pmids\": [\"14712220\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"APE1 inhibits WRN helicase activity on single-strand break BER intermediates (likely by occupying the AP site), and this inhibition is relieved by DNA polymerase beta (pol β), suggesting a pol β-mediated handoff of WRN during base excision repair.\",\n      \"method\": \"In vitro helicase assay on BER intermediate substrates; addition of APE1 and pol β proteins\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — in vitro reconstitution, single lab, single method series\",\n      \"pmids\": [\"15385537\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"POT1 strongly stimulates WRN and BLM to unwind long telomeric forked duplexes and D-loop structures in a telomeric-sequence-dependent manner; POT1 binds directly to WRN and BLM in vitro, and full-length POT1 co-precipitates more WRN than BLM from HeLa nuclear extracts.\",\n      \"method\": \"In vitro helicase unwinding assay on telomeric substrates; pulldown and co-immunoprecipitation from nuclear extracts\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — in vitro reconstitution on defined substrates plus reciprocal protein interaction assays, two orthogonal methods\",\n      \"pmids\": [\"16030011\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Both WRN and BLM bind the extreme C-terminal 18-amino-acid tail of FEN-1, a site adjacent to (but distinct from) the PCNA-binding site; WRN facilitates FEN-1 binding to its preferred double-flap substrate through this protein interaction, and WRN and PCNA have additive stimulatory effects on FEN-1 activity.\",\n      \"method\": \"Interaction mapping with FEN-1 deletion mutants; functional stimulation assays with WRN + FEN-1 mutants; binding assays\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — domain mapping with deletion mutants plus in vitro functional assays, two orthogonal methods\",\n      \"pmids\": [\"16326861\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"WRN helicase is inhibited by p53 both in the presence of RPA (on 849-bp M13 substrates) and in the absence of RPA (on short forked duplexes); WRN, RPA, and p53 co-immunoprecipitate in vivo, and p53 inhibits WRN via a binding site on the WRN helicase domain.\",\n      \"method\": \"Co-immunoprecipitation in vivo; in vitro helicase assay with purified WRN, RPA, p53; WRN helicase-domain fragment lacking p53-binding site as control\",\n      \"journal\": \"Cancer research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — in vitro reconstitution with domain-fragment controls plus in vivo co-IP, two orthogonal methods\",\n      \"pmids\": [\"15735006\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"The Pso4 mRNA splicing complex (Pso4/Prp19, Cdc5L, Plrg1, Spf27) is required for ICL processing in vitro, physically associates with WRN through a direct WRN–Cdc5L interaction, and WRN helicase (but not exonuclease) activity is required for ICL processing.\",\n      \"method\": \"In vitro ICL processing biochemical assay; co-immunoprecipitation; direct binding assay between WRN and Cdc5L; WRN helicase- and exonuclease-mutant analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — in vitro reconstitution of ICL processing plus direct protein binding and domain-mutant dissection, multiple orthogonal methods\",\n      \"pmids\": [\"16223718\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Crystal structures of the WRN exonuclease domain reveal a two-metal-ion nuclease mechanism; active-site mutations inactivate the exonuclease; Ku70/80 specifically stimulates WRN exonuclease activity; structure-based WRN-exo mutants alter DNA end joining in human cells. WRN-exo shares structural and mechanistic homology with DnaQ-family replicative proofreading exonucleases.\",\n      \"method\": \"X-ray crystallography (metal-ion complex structures); active-site mutagenesis + in vitro exonuclease assay; Ku70/80 stimulation assay; DNA end-joining assay in human cells with WRN-exo mutants\",\n      \"journal\": \"Nature structural & molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure plus active-site mutagenesis plus in vitro biochemistry plus cellular assay, multiple orthogonal methods in one study\",\n      \"pmids\": [\"16622405\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"WRN catalyzes ATP-dependent replication fork regression and Holliday junction formation in vitro; this is enhanced on forks with single-stranded gaps (≥11–13 nt) on the leading arm, and WRN exonuclease activity promotes regression by digesting the leading daughter strand to create an optimal substrate.\",\n      \"method\": \"In vitro fork regression assay with model replication fork substrates; ATP-dependence assay; comparison of wild-type vs. exonuclease-deficient WRN\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution with defined substrates, mechanistic dissection of exonuclease contribution, multiple substrate variants\",\n      \"pmids\": [\"17717003\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"SIRT1 interacts with WRN in vitro and in vivo (interaction enhanced after DNA damage); WRN is acetylated by CBP/p300; SIRT1 deacetylates WRN in vitro and in vivo; WRN acetylation decreases its helicase and exonuclease activities; SIRT1-mediated deacetylation reverses this; acetylation alters WRN nuclear distribution and SIRT1 knockdown reduces WRN translocation from nucleoplasm to nucleoli after DNA damage.\",\n      \"method\": \"Co-immunoprecipitation in vitro and in vivo; acetylation/deacetylation assays; in vitro helicase/exonuclease activity assays on acetylated vs. unacetylated WRN; immunofluorescence for nuclear distribution\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — multiple orthogonal methods (co-IP, in vitro enzymatic assays, localization), independently validated across different experimental approaches\",\n      \"pmids\": [\"18203716\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"DNA ligase IIIα and WRN form a complex recruited to DSBs in CML cells; knockdown of either protein increases accumulation of unrepaired DSBs; WRN is up-regulated in BCR-ABL-positive CML cells where it participates in an alternative NHEJ pathway.\",\n      \"method\": \"Co-immunoprecipitation; siRNA knockdown with γ-H2AX DSB accumulation readout; recruitment to DSB foci\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP plus knockdown with functional DSB readout, two orthogonal methods, single lab\",\n      \"pmids\": [\"18524993\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"p300 acetylates WRN, stimulating its catalytic activities in vitro and in vivo; acetylated WRN enhances pol β-mediated strand displacement synthesis more than unacetylated WRN; sodium butyrate (HDAC inhibitor) stimulates long-patch BER in wild-type but not WRN-depleted cells, placing acetylated WRN in the long-patch BER pathway.\",\n      \"method\": \"In vitro acetylation and helicase/exonuclease activity assays; strand displacement synthesis assay; cellular BER assay with HDAC inhibitor and WRN depletion\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — in vitro biochemical reconstitution plus cellular epistasis assay, two orthogonal methods\",\n      \"pmids\": [\"18398454\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"WRN is required for ATM pathway activation in response to psoralen ICL-induced DSBs: WRN depletion impairs the intra-S checkpoint, reduces ATM activation and downstream phosphorylation of ATM targets, and increases γ-H2AX levels, indicating WRN facilitates ATM activation at collapsed replication forks.\",\n      \"method\": \"RNAi knockdown of WRN; immunoblot for ATM and ATM-target phosphorylation; S-phase checkpoint (BrdU incorporation); γ-H2AX measurement\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA epistasis with multiple downstream phosphorylation readouts, single lab\",\n      \"pmids\": [\"18596239\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"WRN controls formation of extrachromosomal telomeric circles: WRN helicase is required for TRF2ΔB-mediated telomere shortening via t-loop homologous recombination; both WRN exonuclease and helicase activities are required to suppress spontaneous telomeric circle formation in telomerase-positive WS fibroblasts.\",\n      \"method\": \"Complementation of WS cells with wild-type vs. exonuclease- or helicase-dead WRN mutants; telomeric circle assay; telomere length analysis\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — structure-function mutagenesis with two catalytic domain mutants plus quantitative telomeric circle assay, single lab\",\n      \"pmids\": [\"18212065\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"WRN is required to repair abnormal replication structures caused by c-Myc-driven S-phase acceleration; depletion of WRN in c-Myc-overexpressing primary human fibroblasts increases DNA damage specifically at replication foci, activating an ATR–CHK1–CHK2–p53 'replication stress' pathway leading to senescence.\",\n      \"method\": \"WRN siRNA depletion in c-Myc-overexpressing fibroblasts; γ-H2AX co-staining with BrdU; pathway inhibitor analysis; p53 rescue experiment\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — knockdown with defined cellular phenotype and pathway placement via rescue experiment, single lab\",\n      \"pmids\": [\"19554081\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"ATR directly phosphorylates WRN at multiple C-terminal S/TQ residues; loss of ATR-mediated phosphorylation prevents WRN accumulation in nuclear foci and co-localization with RPA, causing breakage of stalled forks; ATM kinase phosphorylation of WRN is required for RAD51 recruitment and replication recovery after fork collapse.\",\n      \"method\": \"Expression of ATR/ATM-unphosphorylatable WRN alleles; immunofluorescence for WRN foci and RPA co-localization; DNA fiber assay; RAD51 recruitment assay; in vitro kinase assay\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — in vitro kinase assay plus structure-function allele analysis with multiple cellular readouts, single lab with multiple methods\",\n      \"pmids\": [\"20802463\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"BCR-ABL induces WRN tyrosine phosphorylation (through direct complex formation with WRN) and stimulates WRN helicase and exonuclease activities; activated WRN protects BCR-ABL-positive cells from oxidative/genotoxic stress and promotes unfaithful HR and SSA recombination repair.\",\n      \"method\": \"Co-immunoprecipitation of WRN-BCR/ABL complex; tyrosine phosphorylation assay; in vitro helicase/exonuclease activity assays after BCR-ABL stimulation; siRNA knockdown with survival and repair readouts\",\n      \"journal\": \"Cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP plus in vitro activity assays plus cellular knockdown phenotype, single lab\",\n      \"pmids\": [\"21123451\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"WRN interacts with PCNA in the absence of DNA damage; DNA damage induces dissociation of PCNA from WRN in an ATM/NBS1-dependent manner, leading to PCNA ubiquitination required for TLS; WRN participates in translesion synthesis through NBS1-FHA-domain-mediated interaction and NBS1-dependent WRN phosphorylation.\",\n      \"method\": \"Co-immunoprecipitation; PCNA ubiquitination assay; nuclear focus formation; epistasis with NBS1-FHA domain mutants\",\n      \"journal\": \"Mechanisms of ageing and development\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP plus ubiquitination assay plus domain-mutant epistasis, single lab\",\n      \"pmids\": [\"20600238\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"DHX9 (RNA helicase A) stimulates WRN helicase unwinding of RNA-containing Okazaki fragment-like hybrids and RNA-containing 'chicken-foot' structures in vitro, suggesting cooperative function at replication forks; WRN preferentially unwinds RNA-containing substrates while DHX9 alone fails to unwind Okazaki fragment-like hybrids.\",\n      \"method\": \"In vitro helicase unwinding assay with synthetic RNA-containing substrates; stimulation experiments with purified DHX9\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — in vitro reconstitution, single lab, single method\",\n      \"pmids\": [\"20385589\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"WRN exonuclease activity is blocked by 3′ obstructive groups (3′-phosphate, 3′-phosphoglycolate, 3′-tyrosyl); WRN degrades 3′-OH substrates non-processively but cannot excise any of these common oxidative damage termini.\",\n      \"method\": \"In vitro exonuclease activity assay on substrates with defined 3′ blocking lesions; side-by-side comparison with APE1, TREX1, p53\",\n      \"journal\": \"Mechanisms of ageing and development\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution with chemically defined substrates and comparative controls, single lab\",\n      \"pmids\": [\"17224176\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Acetylation of WRN at 6 specific lysine residues (by CBP/p300) stabilizes WRN protein by inhibiting ubiquitination; SIRT1 deacetylation reverses this stabilization; CBP dramatically increases WRN half-life in a manner abolished by the 6KR (lysine-to-arginine) acetylation-site mutant; WRN is strongly acetylated and stabilized after MMC treatment.\",\n      \"method\": \"Identification of acetylation sites; 6KR mutant stability assay; ubiquitination assay; half-life measurement with cycloheximide chase; MMC treatment acetylation assay; cell survival of 6KR mutant cells\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — site identification with mutagenesis, ubiquitination assay, half-life measurement, functional cellular readout, multiple orthogonal approaches\",\n      \"pmids\": [\"20428248\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"XPG interacts directly with WRN through their C-terminal domains and co-localizes with WRN in S-phase nuclear foci at stalled replication forks; the XPG C-terminal domain strongly stimulates WRN helicase activity; XPG itself possesses intrinsic strand annealing activity that cooperates with WRN annealing activity.\",\n      \"method\": \"Co-immunoprecipitation; domain-mapping with C-terminal deletion mutants; in vitro helicase stimulation assay; in vitro strand annealing assay; immunofluorescence co-localization\",\n      \"journal\": \"Cell cycle (Georgetown, Tex.)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — direct interaction mapping plus in vitro helicase stimulation and annealing assays plus cellular co-localization, multiple orthogonal methods\",\n      \"pmids\": [\"21558802\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"WRN acts epistatically with DNA2 to promote long-range 5′-to-3′ DNA end resection at DSBs in human cells; WRN and DNA2 interact physically and coordinate enzymatic activities to mediate 5′-to-3′ resection in vitro in an RPA-dependent manner; CDK1-mediated phosphorylation of WRN at S1133 is required for interaction with the MRE11 complex to promote DNA2-dependent resection.\",\n      \"method\": \"Epistasis analysis by siRNA co-depletion (resection assay); co-immunoprecipitation of WRN-DNA2; in vitro resection assay with purified proteins; DNA fiber analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — in vitro biochemical reconstitution plus in vivo epistasis plus physical interaction, replicated across multiple orthogonal approaches\",\n      \"pmids\": [\"25122754\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"WRN has a nonenzymatic function in preserving nascent DNA strands at replication-associated DSBs: the NBS1 FHA domain recruits WRN to replication-associated DSBs where WRN stabilizes RAD51 and limits MRE11 exonuclease activity on nascent strands, independent of WRN's own catalytic activities.\",\n      \"method\": \"DNA fiber assay for nascent strand length; NBS1-FHA domain interaction mapping; RAD51 focus formation assay; MRE11 inhibitor epistasis; WRN catalytic mutant analysis\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — domain-mutant epistasis plus fiber assay plus focus formation, multiple orthogonal methods in one study\",\n      \"pmids\": [\"25456133\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"TRF2 specifically stimulates WRN-mediated strand exchange between telomeric substrates (but not non-telomeric substrates); TRF2 basic domain is critical for this stimulation; TRF1 (with similar telomeric DNA binding affinity) has minimal effect; TRF2 is displaced from telomeric DNA by WRN independently of WRN ATPase/helicase activities.\",\n      \"method\": \"In vitro strand exchange assay with telomeric substrates; domain mutant analysis (TRF2 basic domain); comparison with TRF1; ATPase/helicase mutant WRN controls\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution with defined substrates, multiple domain and catalytic mutant controls\",\n      \"pmids\": [\"24880691\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"The WRN exonuclease domain protects nascent strands from MRE11/EXO1-dependent degradation at perturbed replication forks: loss of WRN exonuclease enhances nascent strand degradation by MRE11/EXO1 downstream of RAD51, while loss of WRN helicase reduces exonucleolytic processing and causes genome instability.\",\n      \"method\": \"DNA fiber assay for nascent strand degradation; WRN exonuclease-specific and helicase-specific mutant analysis in cells; MRE11/EXO1 inhibitor epistasis; RAD51 epistasis\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — domain-specific mutagenesis with multiple epistasis experiments and quantitative fiber assay, single lab\",\n      \"pmids\": [\"26275776\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"WRN regulates pathway choice between classical NHEJ and alternative NHEJ at DSBs: WRN promotes c-NHEJ via its helicase and exonuclease activities; WRN inhibits alt-NHEJ using non-enzymatic functions by suppressing MRE11/CtIP recruitment and protecting DSBs from 5′ end resection; WRN knockdown combined with TRF2 depletion increases telomere fusions abrogated by CtIP knockdown.\",\n      \"method\": \"WRN knockdown + enzymatic mutant complementation; end resection assay; MRE11/CtIP recruitment assay at DSBs; telomere fusion assay in mouse embryonic fibroblasts with double knockdown\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — structure-function mutagenesis distinguishing enzymatic vs. non-enzymatic roles, plus epistasis with CtIP, multiple cellular readouts\",\n      \"pmids\": [\"27922005\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"CDK1 phosphorylates WRN at serine S1133 at collapsed replication forks; S1133 phosphorylation is required for WRN interaction with the MRE11 complex (but not for WRN focus formation); loss of S1133 phosphorylation prevents DNA2-dependent long-range resection, impairs HR and replication recovery, and licenses NHEJ at collapsed forks in a dominant-negative manner.\",\n      \"method\": \"In vitro CDK1 kinase assay; phospho-specific antibody; S1133A/D phosphomimetic mutant cells; MRE11 co-IP; DNA fiber and resection assays\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — in vitro kinase assay plus phosphomimetic mutant cellular analysis plus co-IP and resection assays, multiple orthogonal methods\",\n      \"pmids\": [\"27634057\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"ATR-mediated phosphorylation of WRN at serine S1141 leads to ubiquitination and proteasomal degradation of WRN; this dynamic interaction regulates WRN's association with perturbed replication forks, suppresses new origin firing, and is critical for RAD51-dependent DSB repair and prevention of chromosome breakage during replication stress.\",\n      \"method\": \"In vivo S1141 phosphorylation identification; phosphomimetic/phospho-dead mutant analysis; ubiquitination assay; DNA fiber analysis for origin firing; RAD51 focus assay\",\n      \"journal\": \"Oncotarget\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — site-specific phosphomimetic mutagenesis with ubiquitination assay and multiple cellular readouts, single lab\",\n      \"pmids\": [\"26695548\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"WRN helicase reciprocates along the same ssDNA strand during DNA unwinding (rather than dissociating and rebinding or strand-switching), with limited processivity; this reciprocating mechanism was shown on forked, overhanging, and G-quadruplex-containing DNA substrates.\",\n      \"method\": \"Single-molecule FRET (smFRET) analysis of WRN unwinding mechanism on defined substrates\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — single-molecule reconstitution, single lab, single method\",\n      \"pmids\": [\"28266653\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Multiple RPA molecules convert WRN from a weak, repetitive (few-tens-of-bp) helicase into a 'superhelicase' capable of unidirectional unwinding of >1 kb dsDNA; single-molecule FRET and magnetic tweezers demonstrate that binding of multiple RPAs to WRN fundamentally alters its activity and processivity.\",\n      \"method\": \"Single-molecule FRET; magnetic tweezers; titration of RPA molecules on WRN helicase activity\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — single-molecule reconstitution with two orthogonal biophysical methods, clear mechanistic insight\",\n      \"pmids\": [\"29668972\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"HERC2 facilitates RPA association with BLM and WRN helicase complexes through HERC2's HECT E3 ubiquitin ligase activity that ubiquitinates RPA2, enabling RPA release onto ssDNA; HERC2 depletion dissociates RPA from WRN/BLM complexes and increases G-quadruplex DNA formation; epistasis analysis shows HERC2 acts through BLM and WRN for G4 suppression.\",\n      \"method\": \"Co-immunoprecipitation; CRISPR/Cas9 deletion of HERC2 E3 catalytic site; RPA2 ubiquitination assay; G4 staining; siRNA epistasis (triple depletion); in vitro RPA release assay\",\n      \"journal\": \"Cancer research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — epistasis by triple depletion plus ubiquitination assay plus in vitro RPA release, multiple orthogonal methods\",\n      \"pmids\": [\"30279242\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"MDM2 acts as an E3 ubiquitin ligase for WRN: MDM2 interacts with WRN in vivo and in vitro, induces WRN ubiquitination and degradation; DNA damage causes WRN translocation to the nucleoplasm followed by MDM2-mediated degradation; MDM2-dependent WRN degradation mediates cellular senescence in a p53-independent manner.\",\n      \"method\": \"Co-immunoprecipitation in vivo and in vitro; ubiquitination assay; WRN protein stability assay; senescence assay with etoposide; ectopic WRN rescue experiment\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP plus ubiquitination assay plus rescue experiment with multiple endpoints, single lab\",\n      \"pmids\": [\"30532073\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"PARP1 protein (but not its enzymatic activity) is required for H2O2- and CEES-induced nucleolar-to-nucleoplasmic translocation of WRN in HeLa cells; CPT-induced WRN translocation is independent of PARP1 protein; gossypol (which disrupts PARP1 protein interactions) abolishes WRN translocation, indicating PARP1-protein interactions mediate this stress-specific shuttling.\",\n      \"method\": \"Immunofluorescence tracking of WRN nucleolar-nucleoplasmic shuttling; PARP1 siRNA knockdown; PARP enzymatic inhibitors vs. gossypol; comparison across multiple genotoxins\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct localization assay with multiple inhibitor conditions and genetic knockdown, single lab\",\n      \"pmids\": [\"31296950\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"WRN helicase activity (but not exonuclease activity) is selectively essential in MSI cancer models in vitro and in vivo; WRN depletion in MSI cells induces DSBs, apoptosis, and cell cycle arrest, but not in microsatellite-stable cells.\",\n      \"method\": \"CRISPR-Cas9 knockout and RNAi screens; helicase-dead vs. exonuclease-dead WRN complementation; in vivo xenograft models; γ-H2AX/apoptosis/cell cycle readouts\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — large-scale genetic screens confirmed by complementation with catalytic mutants and in vivo xenograft models, multiple labs and methods\",\n      \"pmids\": [\"30971823\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Expanded TA-dinucleotide repeats in MSI cells form non-B DNA secondary structures that stall replication forks, activate ATR, and require unwinding by WRN helicase; in the absence of WRN, expanded TA repeats are cleaved by MUS81 nuclease, causing massive chromosome shattering.\",\n      \"method\": \"DNA fiber assay for replication fork stalling; ATR activation assay; TA-repeat expansion measurement in MSI cells; MUS81 epistasis (knockout); WRN depletion in isogenic MSI/MSS cells; cytogenetic analysis of chromosome shattering\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (fiber assay, ATR activation, MUS81 epistasis, cytogenetics) in MSI model cells, mechanistically rigorous\",\n      \"pmids\": [\"32999459\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"WRN helicase ensures efficient restart and limits excessive degradation of stalled replication forks in BRCA2-deficient cancer cells; in vitro, WRN ATPase/helicase restores regressed forks and curtails MRE11 nuclease activity on regressed fork substrates; WRN helicase inhibition traps WRN on chromatin leading to fork stalling, MRE11-dependent nucleolytic degradation, MUS81-dependent DSBs, and elevated NHEJ.\",\n      \"method\": \"In vitro fork restoration/regression assay with purified WRN; WRN helicase inhibitor treatment in BRCA2-deficient cells; DNA fiber assay; MRE11/MUS81 epistasis; BRCA2-deficient xenograft tumor model\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — in vitro reconstitution plus cellular epistasis with inhibitors plus in vivo xenograft, multiple orthogonal methods\",\n      \"pmids\": [\"34772932\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"WRN phosphorylation by CDK2 at serine 426 is critical for DSB repair pathway choice: S426 phosphorylation stabilizes WRN's affinity for RPA and promotes long-range resection required for HR; unphosphorylated WRN shows altered DSB recruitment, reduced RPA interaction, and altered strand annealing and DSB repair activities.\",\n      \"method\": \"In vitro CDK2 kinase assay; phosphomimetic/phospho-dead S426 mutant cells; RPA co-immunoprecipitation; strand annealing assay; DSB repair pathway assay; laser-induced DSB recruitment\",\n      \"journal\": \"Aging cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — in vitro kinase assay plus phosphomimetic mutant analysis with multiple cellular and biochemical readouts, single lab\",\n      \"pmids\": [\"34612580\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"WRN helicase directly unfolds cruciform DNA structures in vitro, preventing cleavage by SLX1-SLX4 structure-specific endonuclease; TA-repeat sequences are particularly prone to form cruciforms; WRN and MMR complex MutLα exhibit synergistic (higher-than-additive) cruciform processing in vitro, suggesting cooperative function.\",\n      \"method\": \"In vitro cruciform DNA unwinding/processing assay; SLX1-SLX4 cleavage assay; TA-repeat cruciform formation assay; combined WRN + MutLα assay\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro biochemical reconstitution with multiple defined substrates and combinatorial enzyme experiments, single lab\",\n      \"pmids\": [\"36541070\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"WRN helicase domain regulates transcriptional expression of SHOX by unwinding G-quadruplex structures in the SHOX promoter region; WRN-null zebrafish exhibit impaired bone growth rescued by SHOX/shox overexpression; chondrogenesis requires WRN and is linked specifically to its helicase domain.\",\n      \"method\": \"WRN/wrn knockout zebrafish model; SHOX identification as WRN target; G-quadruplex unwinding assay; genetic rescue with SHOX overexpression in WRN-null background; in vitro transcription/promoter assay\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — in vitro G4 unwinding assay plus in vivo genetic rescue in zebrafish, two orthogonal methods\",\n      \"pmids\": [\"36114168\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"HRO761, an allosteric WRN helicase inhibitor, binds at the interface of the D1 and D2 helicase domains of WRN, locking it in an inactive conformation; pharmacological inhibition recapitulates WRN-depletion phenotype (DNA damage, selective MSI cell growth inhibition); HRO761 causes WRN degradation in MSI but not MSS cells.\",\n      \"method\": \"X-ray/cryo structural characterization of HRO761-WRN complex; biochemical helicase inhibition assay; selectivity profiling; cellular DNA damage assay; WRN protein stability assay in MSI vs. MSS cells; in vivo xenograft\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — structural characterization plus biochemical assay plus cellular and in vivo validation, multiple orthogonal approaches in one rigorous study\",\n      \"pmids\": [\"38658754\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"VVD-133214, a covalent allosteric WRN inhibitor, selectively engages cysteine C727 in the helicase domain at a region subject to interdomain movement during DNA unwinding; binding is cooperative with nucleotide and stabilizes compact conformations lacking dynamic flexibility for helicase function, causing DSBs and cell death selectively in MSI-H cells.\",\n      \"method\": \"Chemoproteomics identification of C727; covalent binding characterization; nucleotide cooperativity assay; conformational studies; selective cellular toxicity in MSI-H vs. MSS cells; in vivo xenograft models\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — chemoproteomics site identification plus covalent mechanism characterization plus in vivo validation, multiple orthogonal methods\",\n      \"pmids\": [\"38658751\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"WRN (with DNA2) specifically resects the 5′ end of ssDNA gaps through a mechanism distinct from DSB end resection, independent of MRN-CtIP; this 5′-gap resection by DNA2-WRN/BLM alters ssDNA gap repair kinetics and, in BRCA1-deficient cells, excessive resection leads to larger gaps causing DNA breaks in subsequent cell cycles.\",\n      \"method\": \"Single-molecule DNA fiber analysis; electron microscopy; biochemical resection assays with purified proteins; epistasis with MRN-CtIP knockdown; BRCA1-deficient cell analysis\",\n      \"journal\": \"Genes & development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — in vitro biochemical reconstitution plus EM plus fiber analysis plus genetic epistasis, multiple orthogonal methods\",\n      \"pmids\": [\"40127955\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"WRN is a multifunctional RecQ DNA helicase/exonuclease whose core activities (3′→5′ helicase, 3′→5′ exonuclease, strand annealing, and fork regression) are directed to stalled/collapsed replication forks, Holliday junctions, D-loops, cruciform structures, and telomeric substrates; its helicase activity is stimulated by RPA (which converts WRN into a superhelicase capable of unwinding >1 kb), POT1, TRF2, XPG, RECQL5, and DHX9, while its exonuclease is recruited by TRF2 and Ku70/80 to telomeres and DSB ends, respectively; WRN promotes c-NHEJ and CDK1/CDK2-phosphorylation-dependent HR (via DNA2-mediated long-range resection) while suppressing alternative NHEJ through non-enzymatic shielding of DSBs from MRE11/CtIP; post-translational regulation by SIRT1/CBP-p300 acetylation, MDM2/ubiquitin-proteasome degradation, ATR phosphorylation (S1141 for regulated proteasomal turnover), ATM phosphorylation (for RAD51 recruitment), CDK1 phosphorylation (S1133 for MRE11 interaction and DNA2-resection), and CDK2 phosphorylation (S426 for RPA affinity and pathway choice) orchestrate its spatiotemporal deployment; in MSI cancers, WRN helicase is essential to unwind expanded TA-dinucleotide repeat-derived cruciform/non-B structures that would otherwise be cleaved by MUS81, making WRN a synthetic lethal therapeutic target exploited by allosteric covalent inhibitors that lock WRN in an inactive conformation.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"WRN is a multifunctional RecQ-family DNA helicase/exonuclease that directs its catalytic activities to stalled and collapsed replication forks, recombination intermediates, and telomeres to preserve genome stability [#1, #14, #2]. Its core 3′→5′ helicase and 3′→5′ exonuclease activities act on Holliday junctions, D-loops, replication forks, cruciforms, and G-quadruplexes, catalyzing ATP-dependent fork regression and strand annealing [#1, #2, #14, #44]; single-molecule analyses show WRN unwinds by reciprocating along ssDNA with limited intrinsic processivity, but multiple RPA molecules convert it into a unidirectional 'superhelicase' capable of unwinding >1 kb [#35, #36]. WRN activity is shaped by an extensive partner network that targets it to specific substrates: RPA and XPG stimulate its helicase at stalled forks [#1, #27], POT1 and TRF2 stimulate telomeric helicase/exonuclease and strand exchange [#9, #7, #30], Ku70/80 stimulates the exonuclease at DSB ends [#13], and p53 inhibits the helicase [#11]. At replication forks and DSBs WRN coordinates end resection by acting epistatically with DNA2 to drive long-range 5′→3′ resection for homologous recombination, while also resecting the 5′ ends of ssDNA gaps through a distinct MRN-CtIP-independent route [#28, #48]; it additionally serves non-enzymatic structural roles, stabilizing RAD51 and shielding nascent strands and DSBs from MRE11/CtIP to promote classical NHEJ and suppress alternative NHEJ [#29, #31, #32]. Deployment is orchestrated by post-translational modification: ATR phosphorylation at S1141 drives ubiquitin-proteasomal turnover [#34], ATM phosphorylation enables RAD51 recruitment [#21], CDK1 phosphorylation at S1133 licenses MRE11 interaction and DNA2 resection [#33], CDK2 phosphorylation at S426 tunes RPA affinity and DSB pathway choice [#43], and CBP/p300 acetylation (reversed by SIRT1) regulates activity, localization, and MDM2-dependent stability [#15, #26, #38]. In microsatellite-instable cancers WRN helicase is selectively essential to unwind expanded TA-dinucleotide-repeat cruciform/non-B structures that, absent WRN, are cleaved by MUS81 to cause chromosome shattering, establishing WRN as a synthetic-lethal target now drugged by allosteric covalent helicase inhibitors that lock it in an inactive conformation [#40, #41, #46, #47].\",\n  \"teleology\": [\n    {\n      \"year\": 1999,\n      \"claim\": \"Established that WRN helicase is not an autonomous enzyme but is functionally coupled to the single-strand binding protein RPA, defining the first key cofactor that enables long-range unwinding.\",\n      \"evidence\": \"Co-IP of purified proteins and in vitro helicase assays on long duplex substrates comparing RPA to bacterial/phage SSBs\",\n      \"pmids\": [\"10373438\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not resolve stoichiometry or the conformational basis of RPA stimulation\", \"No cellular demonstration of the interaction at forks\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Defined WRN's substrate repertoire beyond simple duplexes by showing it disrupts D-loops, stimulates FEN-1 flap cleavage, and operates within an RNA polymerase I complex, linking it to recombination, Okazaki processing, and rRNA transcription.\",\n      \"evidence\": \"In vitro biochemistry on D-loop and flap substrates; co-IP with RPI subunit RPA40 and complementation of WS fibroblasts\",\n      \"pmids\": [\"12427008\", \"12356323\", \"11971179\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Relative physiological weighting of these activities unresolved\", \"Nucleolar role mechanistically distinct from fork roles\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Distinguished WRN's catalytic from structural contributions to repair, showing a non-enzymatic scaffolding role in NHEJ/HR optimization separable from helicase/exonuclease activity, and a functional RAD52 interaction at forks.\",\n      \"evidence\": \"Complementation of WRN-null cells with enzymatic-dead mutants in NHEJ/HR assays; in vivo FRET and in vitro reconstitution with RAD52\",\n      \"pmids\": [\"12934712\", \"12750383\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular basis of the structural role not defined at this stage\", \"Which DSB substrates require scaffolding vs catalysis unclear\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Identified telomere- and DSB-specific recruiters that target WRN's exonuclease, showing TRF2 directs WRN to telomeric substrates and Ku70/80 to DNA ends.\",\n      \"evidence\": \"DNA-independent pulldowns and in vitro exonuclease assays on telomeric substrates (TRF2); later crystallographic work with Ku70/80 stimulation\",\n      \"pmids\": [\"14712220\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo consequences of TRF2-directed exonuclease not yet established\", \"Selectivity of stimulation for exonuclease over helicase not mechanistically explained\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Provided the structural and catalytic basis of the WRN exonuclease, defining a two-metal-ion DnaQ-family proofreading mechanism and confirming Ku70/80 stimulation and a role in cellular end joining.\",\n      \"evidence\": \"X-ray crystallography of metal-ion complexes plus active-site mutagenesis, in vitro exonuclease assays, and DNA end-joining assays in human cells\",\n      \"pmids\": [\"16622405\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structure of the helicase domain and full-length enzyme not solved here\", \"How exonuclease and helicase domains are coordinated unresolved\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Demonstrated WRN catalyzes ATP-dependent replication fork regression with its exonuclease shaping the substrate, mechanistically placing WRN in the protection and remodeling of stalled forks.\",\n      \"evidence\": \"In vitro fork regression assays on model substrates comparing wild-type and exonuclease-deficient WRN\",\n      \"pmids\": [\"17717003\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo regulation of fork regression by WRN not addressed\", \"Coordination with other fork-remodeling enzymes unknown\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Revealed acetylation as a major regulatory layer, with CBP/p300 acetylation tuning WRN activity and localization and SIRT1 reversing it, while also placing WRN in long-patch BER, ATM checkpoint activation, and alt-NHEJ in CML.\",\n      \"evidence\": \"Acetylation/deacetylation and activity assays; HDAC-inhibitor BER epistasis; RNAi with ATM-target phosphorylation readouts; co-IP with DNA ligase IIIα in CML cells\",\n      \"pmids\": [\"18203716\", \"18398454\", \"18596239\", \"18524993\", \"18212065\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Causal hierarchy among acetylation, localization, and activity changes incompletely ordered\", \"Context dependence of pro- vs anti-recombinogenic roles unresolved\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Placed WRN in the cellular response to oncogene-driven replication stress, showing its loss converts c-Myc-accelerated S-phase into ATR–CHK1–p53 signaling and senescence.\",\n      \"evidence\": \"WRN siRNA in c-Myc-overexpressing fibroblasts with γ-H2AX/BrdU staining and pathway inhibitor and p53 rescue analysis\",\n      \"pmids\": [\"19554081\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct DNA substrate engaged under oncogenic stress not defined\", \"Single cell system without biochemical reconstitution\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Defined the kinase control of WRN's fork localization and stability, with ATR/ATM phosphorylation governing focus formation, RPA co-localization, and RAD51 recruitment, and established further telomeric (POT1) and fork (DHX9) cofactors plus exonuclease limits at oxidative lesions.\",\n      \"evidence\": \"ATR/ATM-unphosphorylatable alleles with fiber and focus assays; in vitro helicase stimulation by POT1 and DHX9; exonuclease assays on 3′-blocked substrates; PCNA/NBS1 TLS co-IPs\",\n      \"pmids\": [\"20802463\", \"16030011\", \"20385589\", \"17224176\", \"20600238\", \"21123451\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Site-resolved ATR/ATM target residues not fully mapped at this stage\", \"Integration of multiple kinase inputs not yet unified\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Identified XPG as a direct C-terminal partner that stimulates WRN helicase and cooperates in strand annealing at stalled forks, expanding the fork-associated WRN interactome.\",\n      \"evidence\": \"Co-IP, domain mapping, in vitro helicase/annealing assays, and S-phase co-localization\",\n      \"pmids\": [\"21558802\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Physiological pathway in which WRN-XPG operates not defined in cells\", \"Whether XPG nuclease activity is involved unaddressed\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Resolved WRN's role in DSB end resection, showing it acts with DNA2 for RPA-dependent long-range resection (with CDK1-phospho-S1133 enabling MRE11 interaction) while also non-enzymatically protecting nascent strands via NBS1 recruitment.\",\n      \"evidence\": \"siRNA epistasis, WRN-DNA2 co-IP, in vitro resection with purified proteins, DNA fiber assays, NBS1-FHA domain mapping, catalytic-mutant analysis\",\n      \"pmids\": [\"25122754\", \"25456133\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Switch between resection-promoting and strand-protecting modes not fully defined\", \"Relative contributions of WRN catalysis vs DNA2 unclear in vivo\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Separated the opposing domain functions at perturbed forks, showing the WRN exonuclease protects nascent strands from MRE11/EXO1 degradation while the helicase enables proper exonucleolytic processing downstream of RAD51.\",\n      \"evidence\": \"Domain-specific mutant analysis with DNA fiber assays and MRE11/EXO1/RAD51 epistasis\",\n      \"pmids\": [\"26275776\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How the two domains are temporally coordinated at a single fork unresolved\", \"Regulatory signal selecting protection vs processing not identified\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Established WRN as an arbiter of DSB pathway choice and detailed the phospho-regulation underlying it, promoting classical NHEJ enzymatically while non-enzymatically suppressing alt-NHEJ, with CDK1-S1133 licensing DNA2 resection and ATR-S1141 driving turnover.\",\n      \"evidence\": \"Knockdown plus enzymatic-mutant complementation, end-resection and MRE11/CtIP recruitment assays, telomere fusion assays, in vitro CDK1 kinase assay with phosphomimetic mutants and ubiquitination assays\",\n      \"pmids\": [\"27922005\", \"27634057\", \"26695548\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Integration of CDK1 and ATR inputs into a single decision model incomplete\", \"Cell-cycle timing of pathway switching not fully resolved\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Mechanistically explained how RPA reprograms WRN and how that loading is regulated, showing multiple RPAs create a >1 kb superhelicase, HERC2-mediated RPA2 ubiquitination enables RPA handoff, and MDM2 ubiquitinates WRN to drive p53-independent senescence.\",\n      \"evidence\": \"Single-molecule FRET and magnetic tweezers; HERC2 E3-dead CRISPR lines with RPA2 ubiquitination and G4 assays; MDM2 co-IP, ubiquitination, stability, and senescence rescue assays\",\n      \"pmids\": [\"29668972\", \"30279242\", \"30532073\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How superhelicase behavior is engaged at specific in vivo substrates unresolved\", \"Cross-talk between MDM2 and ATR/acetylation-dependent turnover not unified\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Identified the dependency that makes WRN a cancer target, showing WRN helicase (not exonuclease) is selectively essential in microsatellite-instable cells where its loss triggers DSBs and death.\",\n      \"evidence\": \"CRISPR/RNAi screens, helicase- vs exonuclease-dead complementation, and in vivo xenografts with damage/apoptosis readouts\",\n      \"pmids\": [\"30971823\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular nature of the MSI-specific substrate not defined in this study\", \"Why helicase but not exonuclease is essential left for follow-up\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Defined the MSI synthetic-lethal mechanism, showing expanded TA-dinucleotide repeats form non-B structures that stall forks and, without WRN unwinding, are cleaved by MUS81 to shatter chromosomes.\",\n      \"evidence\": \"DNA fiber stalling assays, ATR activation, TA-repeat measurement, MUS81 epistasis, and cytogenetics in isogenic MSI/MSS cells\",\n      \"pmids\": [\"32999459\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Full spectrum of non-B structures resolved by WRN not enumerated\", \"Whether other nucleases contribute to shattering unaddressed\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Extended WRN's fork-protective role to BRCA2-deficient contexts and refined resection pathway choice, showing WRN helicase limits MRE11 degradation of regressed forks and CDK2-S426 phosphorylation stabilizes RPA binding to direct HR.\",\n      \"evidence\": \"In vitro fork restoration assays, helicase-inhibitor treatment with MRE11/MUS81 epistasis and xenografts; in vitro CDK2 kinase assay with S426 phosphomimetic mutants and RPA co-IP\",\n      \"pmids\": [\"34772932\", \"34612580\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How CDK2-S426 and CDK1-S1133 signals are coordinated unresolved\", \"In vivo therapeutic window in BRCA2-deficient tumors not fully defined\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Linked WRN's structure-resolving helicase to broader physiology and to anti-nuclease protection, showing it unfolds cruciforms to prevent SLX1-SLX4 cleavage (synergizing with MutLα) and unwinds promoter G-quadruplexes to drive SHOX expression and chondrogenesis.\",\n      \"evidence\": \"In vitro cruciform/SLX1-SLX4 and combined MutLα assays; WRN-null zebrafish with G4 unwinding assays and SHOX rescue\",\n      \"pmids\": [\"36541070\", \"36114168\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Generality of transcriptional G4-resolving role across loci unknown\", \"Mechanistic basis of WRN-MutLα synergy not defined\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Delivered structurally defined allosteric WRN inhibitors, showing HRO761 binds the D1-D2 helicase interface and VVD-133214 covalently engages cysteine C727 to lock WRN inactive and selectively kill MSI-H cells.\",\n      \"evidence\": \"Structural and chemoproteomic characterization, biochemical helicase inhibition, conformational/nucleotide cooperativity studies, and MSI-selective cellular and xenograft validation\",\n      \"pmids\": [\"38658754\", \"38658751\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Long-term resistance mechanisms to WRN inhibition not characterized\", \"Differential WRN degradation in MSI vs MSS cells mechanistically incomplete\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Distinguished WRN's gap-resection activity from DSB resection, showing DNA2-WRN/BLM resects 5′ ends of ssDNA gaps independently of MRN-CtIP and that excessive resection in BRCA1-deficient cells generates damaging gaps.\",\n      \"evidence\": \"Single-molecule fiber analysis, electron microscopy, in vitro resection with purified proteins, and MRN-CtIP epistasis in BRCA1-deficient cells\",\n      \"pmids\": [\"40127955\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How gap vs DSB resection modes are selected in cells unresolved\", \"Regulatory inputs controlling the extent of gap resection unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How the full set of post-translational signals (ATR/ATM/CDK1/CDK2 phosphorylation, acetylation, MDM2/HERC2 ubiquitination) is integrated in real time to choose among fork regression, gap resection, DSB resection, NHEJ promotion, and degradation at a given lesion remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No unified quantitative model linking modification state to substrate choice\", \"Structure of full-length WRN engaging physiological substrates lacking\", \"Lesion-context determinants of enzymatic vs non-enzymatic deployment undefined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140657\", \"supporting_discovery_ids\": [0, 14, 35, 36]},\n      {\"term_id\": \"GO:0140097\", \"supporting_discovery_ids\": [2, 13, 14, 28, 48]},\n      {\"term_id\": \"GO:0003677\", \"supporting_discovery_ids\": [1, 2, 44, 45]},\n      {\"term_id\": \"GO:0016787\", \"supporting_discovery_ids\": [13, 25, 14]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [3, 10, 29, 32]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005654\", \"supporting_discovery_ids\": [1, 15, 39]},\n      {\"term_id\": \"GO:0005730\", \"supporting_discovery_ids\": [4, 15, 39]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [1, 21]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-73894\", \"supporting_discovery_ids\": [13, 28, 32, 48]},\n      {\"term_id\": \"R-HSA-69306\", \"supporting_discovery_ids\": [1, 14, 31, 42]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [40, 41, 46, 47]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [4, 45]},\n      {\"term_id\": \"R-HSA-8953854\", \"supporting_discovery_ids\": [12, 24]}\n    ],\n    \"complexes\": [\"RNA polymerase I complex\", \"Pso4/Prp19 splicing complex\"],\n    \"partners\": [\"RPA\", \"TRF2\", \"POT1\", \"DNA2\", \"XPG\", \"FEN1\", \"NBS1\", \"MDM2\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}