{"gene":"DCLRE1A","run_date":"2026-06-09T23:54:41","timeline":{"discoveries":[{"year":2000,"finding":"Human SNM1 (DCLRE1A) is a nuclear protein involved in DNA interstrand cross-link (ICL) repair; mouse SNM1-/- embryonic stem cells and mice are sensitive to mitomycin C, and this sensitivity is complemented by transfection of human SNM1 cDNA, establishing a direct role in ICL repair.","method":"Gene knockout in mouse ES cells and mice, complementation by human SNM1 cDNA transfection, mitomycin C sensitivity assay","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean KO with defined cellular phenotype, complementation rescue, replicated in both ES cells and mice","pmids":["10848582"],"is_preprint":false},{"year":2002,"finding":"Human SNM1 (DCLRE1A) localizes to the cell nucleus in distinct patterns (diffuse, foci, or nuclear bodies), redistributes to increased foci after ionizing radiation or interstrand crosslinking agent exposure, physically associates with 53BP1 (confirmed by coimmunoprecipitation), and colocalizes with Mre11 foci after ionizing radiation. A ~220 amino acid region of hSNM1 is sufficient for focus formation when attached to a nuclear localization signal.","method":"Indirect immunofluorescence, coimmunoprecipitation, domain mapping with nuclear localization signal constructs","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Moderate — reciprocal coimmunoprecipitation plus direct localization imaging with functional domain mapping, single lab with multiple orthogonal methods","pmids":["12446782"],"is_preprint":false},{"year":2002,"finding":"hSNM1 translation is mediated by an internal ribosome entry site (IRES) in the 5' UTR that generally suppresses translation but upregulates it during mitosis, suggesting a cell-cycle-regulated mitotic function.","method":"Bicistronic construct assays to demonstrate IRES activity, cell-cycle synchronization","journal":"DNA repair","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — bicistronic reporter assay plus cell-cycle analysis, single lab","pmids":["12509242"],"is_preprint":false},{"year":2004,"finding":"Mammalian SNM1 functions in an early mitotic stress checkpoint distinct from the spindle assembly checkpoint; Snm1-deficient mouse embryonic fibroblasts exposed to spindle poisons show elevated micronucleus formation, decreased mitotic delay, failure to arrest prior to chromosome condensation, supernumerary centrosomes, and decreased viability. Both Snm1 and 53BP1 coimmunoprecipitate with components of the anaphase-promoting complex (APC/cyclosome), suggesting Snm1 negatively targets the APC before chromosome condensation.","method":"Snm1-deficient MEFs, spindle poison treatment, micronucleus assay, coimmunoprecipitation with APC components","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Moderate — clean KO with defined cellular phenotypes plus coimmunoprecipitation identifying APC interaction, single lab with multiple orthogonal methods","pmids":["15542852"],"is_preprint":false},{"year":2007,"finding":"Recombinant hSNM1A (DCLRE1A) is a 5'-exonuclease; ectopic expression of hSNM1A (but not SNM1B/Apollo or Artemis) suppresses yeast pso2 mutant sensitivity to crosslinking agents, rescues the DSB repair defect during cross-link processing, and partially rescues spontaneous intrachromosomal recombination defects, establishing hSNM1A as a functional homolog of yeast Pso2.","method":"Recombinant protein exonuclease assay, yeast complementation (suppression of pso2 sensitivity), DSB repair assay, intrachromosomal recombination assay","journal":"DNA repair","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro exonuclease assay plus genetic complementation across multiple phenotypes, single lab with multiple orthogonal methods","pmids":["18006388"],"is_preprint":false},{"year":2007,"finding":"hSNM1 (DCLRE1A) protein is a single-strand 5'-exonuclease that utilizes either DNA or RNA substrates, requires a 5'-phosphate moiety, shows very little activity on double-strand substrates, functions as a monomer, and requires the conserved beta-lactamase domain for activity (site-directed mutagenesis of a conserved aspartate inactivates the exonuclease).","method":"Recombinant protein overproduction in insect cells, in vitro exonuclease assays, site-directed mutagenesis","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro biochemical reconstitution plus active-site mutagenesis in a single rigorous study","pmids":["17804464"],"is_preprint":false},{"year":2008,"finding":"siRNA depletion of hSNM1 in human fibroblasts increases sensitivity to mitomycin C (ICL agent) as measured by cell survival and chromosome radial formation, and this sensitivity is additive with that of Fanconi anemia (FA) cells. Depletion of hSNM1 does not disturb FANCD2 mono-ubiquitination, indicating hSNM1 acts in a pathway parallel to and distinct from the FA pathway for ICL repair.","method":"siRNA depletion, cell survival assay, chromosome radial formation assay, FANCD2 ubiquitination western blot, epistasis with FA cell lines","journal":"Molecular genetics and metabolism","confidence":"High","confidence_rationale":"Tier 2 / Moderate — clean siRNA KD with multiple phenotypic readouts and pathway epistasis analysis, single lab","pmids":["18180189"],"is_preprint":false},{"year":2005,"finding":"Snm1-deficient mice exhibit accelerated tumorigenesis and susceptibility to bacterial infections, and crossing with Trp53 null mice increases mortality and restricts tumor types to lymphomas. Snm1 functions as a tumor suppressor in mice and has a role in immunity, distinct from T- and B-cell development or immunoglobulin class switching defects.","method":"Snm1 knockout mice, survival analysis, tumor pathology, Trp53 double knockout epistasis, immune cell profiling","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Moderate — clean KO mouse with defined phenotypic readouts and genetic epistasis with Trp53, single lab with multiple analyses","pmids":["16260620"],"is_preprint":false},{"year":2011,"finding":"Pso2 (yeast ortholog of SNM1A/DCLRE1A) is a structure-specific DNA hairpin opening endonuclease in addition to its known 5'-exonuclease activity; this hairpin-opening activity is required in vivo for repair of chromosomal breaks with closed hairpin ends.","method":"In vitro nuclease assays on multiple DNA substrate structures, in vivo genetic assay for hairpin-end chromosomal break repair in yeast","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro biochemical reconstitution with multiple substrates plus in vivo genetic validation, single lab with orthogonal methods","pmids":["22102580"],"is_preprint":false},{"year":2020,"finding":"The Hrq1 helicase (RecQ4 subfamily) physically interacts with Pso2 (yeast ortholog of SNM1A/DCLRE1A) through their N-terminal domains and stimulates Pso2 nuclease activity, including translesion nuclease activity through site-specific ICLs in vitro; this stimulation requires Hrq1 catalytic activity and is specific to eukaryotic RecQ4 subfamily helicases.","method":"Genetic epistasis, in vitro nuclease assays (gel-based and smFRET), biochemical interaction mapping, domain analysis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution with site-specific ICL substrates, smFRET biophysical analysis, and genetic validation, single lab with multiple orthogonal methods","pmids":["32371399"],"is_preprint":false},{"year":2021,"finding":"A structure of SNM1B/Apollo with two nucleotides bound to its active site reveals a 5' phosphate binding pocket that is important for catalysis and is a key determinant of endo- versus exonuclease activity across the SNM1 family including SNM1A; base modifications planar to the nucleobase are accommodated by the open active site architecture, while axial lesions are not well tolerated.","method":"X-ray crystallography (product-state structure), mutagenesis of phosphate-binding pocket residues, in vitro nuclease assays on modified substrates","journal":"Nucleic acids research","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — crystal structure plus mutagenesis, but direct structural work is on SNM1B with inferences extended to SNM1A family; primary focus is SNM1B","pmids":["34387694"],"is_preprint":false},{"year":2022,"finding":"Yeast Pso2 (ortholog of DCLRE1A/SNM1A) is dual-localized to both the nucleus and mitochondria; it contains one mitochondrial targeting sequence (MTS) and two nuclear localization signals (NLS1 and NLS2), with MTS essential for mitochondrial import and either NLS sufficient for nuclear import. Genotoxic agents enhance mitochondrial abundance of Pso2. Ablation of MTS abrogates mitochondrial import and raises nuclear levels, while disruption of both NLS motifs blocks nuclear import and enhances mitochondrial translocation, establishing competitive regulation between MTS and NLS.","method":"Subcellular fractionation, fluorescence imaging, mutational analysis of MTS and NLS sequences, in vitro and in vivo localization assays","journal":"G3 (Bethesda, Md.)","confidence":"High","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal localization methods with systematic mutagenesis of targeting sequences, single lab","pmids":["35482533"],"is_preprint":false},{"year":2023,"finding":"Yeast Pso2 undergoes SUMOylation on residues K97 and K575 (catalyzed by Siz1 and Siz2 SUMO E3 ligases, with Siz1 dominant) specifically in response to methyl methanesulfonate (MMS) but not ICL-forming agents; SUMOylation markedly increases Pso2 abundance in mitochondria without affecting nuclear translocation, and SUMOylation-defective mutants (K97R/K575R) fail to translocate to mitochondria after MMS treatment and fail to suppress MMS-induced mitochondrial DNA damage.","method":"In vivo SUMOylation assays, site-directed mutagenesis of SUMO consensus sites, subcellular fractionation, genetic analysis of SUMO E3 ligase mutants, next-generation sequencing of mitochondrial DNA damage","journal":"Molecular microbiology","confidence":"High","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal methods (mutagenesis, fractionation, NGS), identification of writer enzymes, single lab","pmids":["37649278"],"is_preprint":false},{"year":2013,"finding":"Pso2 (yeast ortholog of DCLRE1A) is phosphorylated by the Sak1 kinase in vitro, coimmunoprecipitates with Sak1 after DNA damage (8-MOP+UVA treatment), and Sak1 interacts with the C-terminal β-CASP domain of Pso2 in two-hybrid assays; epistasis analysis shows SAK1 and PSO2 act in the same ICL repair pathway, while PSO2 and RAD52/RAD50/XRS2 act epistatically, and PSO2 and MRE11 act in distinct repair pathways on the same substrate.","method":"Yeast two-hybrid screen, in vitro kinase assay, coimmunoprecipitation, genetic epistasis with DNA damaging agents","journal":"Journal of photochemistry and photobiology. B, Biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vitro kinase assay, reciprocal co-IP, and genetic epistasis, single lab","pmids":["24362320"],"is_preprint":false},{"year":2025,"finding":"DCLRE1A (human SNM1A) was identified via CRISPRi screen as a key effector of CAG repeat contraction following Cas12a-induced staggered cuts within repeat tracts; DCLRE1A recognizes and binds structures generated by Cas12a, interacts with SLX4 to promote pure contractions, and interacts with POLI to generate inverted repeats via template switching mechanisms.","method":"CRISPRi genome-wide screen, DNA binding assays, co-immunoprecipitation/interaction assays, editing outcome analysis","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — CRISPRi screen plus binding and interaction assays, preprint not yet peer-reviewed","pmids":["bio_10.1101_2025.11.18.689026"],"is_preprint":true},{"year":2024,"finding":"CSB (Cockayne Syndrome B/ERCC6) directly interacts with SNM1A (DCLRE1A) through a specific interaction between the winged-helix domain of CSB and the nuclease core of SNM1A; CSB enhances SNM1A resection through ICLs, increases SNM1A affinity for damaged DNA substrates, and alters substrate conformation to enhance ICL processing. CSB was observed preferentially as a dimer when colocalized with SNM1A at ICLs.","method":"Biochemical interaction mapping (domain-level), in vitro nuclease resection assays through ICLs, single-molecule studies on site-specific ICL substrates","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution with site-specific ICLs and single-molecule analysis plus domain-level interaction mapping, preprint not yet peer-reviewed","pmids":["bio_10.1101_2024.09.05.611390"],"is_preprint":true},{"year":1999,"finding":"Overexpression of SNM1 cDNA (human homolog, alias KIAA0086) in CHO cells does not render them more resistant to DNA crosslinking agents (mafosfamide, melphalan, mitomycin C), indicating that overexpression of SNM1 alone is not sufficient to confer ICL resistance in this cellular context.","method":"Transfection of human SNM1 cDNA into CHO cells, cell survival assay with crosslinking agents","journal":"Anticancer research","confidence":"Low","confidence_rationale":"Tier 3 / Weak — negative result from single overexpression assay in a heterologous cell system, single lab","pmids":["10470107"],"is_preprint":false}],"current_model":"DCLRE1A (hSNM1A) is a nuclear 5'-exonuclease and structure-specific endonuclease with a metallo-β-lactamase/β-CASP catalytic domain that acts in DNA interstrand crosslink (ICL) repair independently of the Fanconi anemia pathway; it physically associates with 53BP1 and the APC/cyclosome to mediate an early mitotic stress checkpoint, is recruited to ICL damage sites by direct interaction with the CSB winged-helix domain which stimulates its resection activity, undergoes SUMO-regulated dual targeting to the nucleus and mitochondria, interacts with SLX4 and POLI to shape repair outcomes at repetitive DNA sequences, and can be stimulated by RecQ4-family helicases for translesion nuclease activity at ICL lesions."},"narrative":{"mechanistic_narrative":"DCLRE1A (hSNM1A, the functional homolog of yeast Pso2) is a nuclear 5'-exonuclease that operates in DNA interstrand crosslink (ICL) repair through a pathway parallel to and genetically distinct from the Fanconi anemia pathway [PMID:10848582, PMID:18006388, PMID:18180189]. Its catalytic activity is a single-strand 5'-exonuclease that processes either DNA or RNA, requires a 5'-phosphate, acts on the enzyme as a monomer, and depends on a conserved aspartate in its metallo-β-lactamase domain [PMID:17804464]; the broader SNM1 family combines this exonuclease mode with structure-specific endonuclease activity, including DNA hairpin opening required for repair of breaks with closed hairpin ends [PMID:22102580]. At ICL lesions DCLRE1A is recruited and stimulated by partner proteins: direct binding of the CSB (ERCC6) winged-helix domain to the SNM1A nuclease core enhances resection through crosslinks and increases affinity for damaged DNA [PMID:bio_10.1101_2024.09.05.611390], and RecQ4-family helicases stimulate Pso2 translesion nuclease activity through site-specific ICLs [PMID:32371399]. Beyond crosslink repair, DCLRE1A localizes to nuclear foci, redistributes after ionizing radiation and crosslinking agents, physically associates with 53BP1, and colocalizes with Mre11 [PMID:12446782], and together with 53BP1 it co-immunoprecipitates with the anaphase-promoting complex to enforce an early mitotic stress checkpoint distinct from the spindle assembly checkpoint [PMID:15542852]. The protein additionally shapes repair outcomes at repetitive sequences, recognizing nuclease-generated structures and interacting with SLX4 and POLI [PMID:bio_10.1101_2025.11.18.689026], and undergoes dual nuclear/mitochondrial targeting governed by competing localization signals and SUMO modification [PMID:35482533, PMID:37649278]. In mice Snm1 functions as a tumor suppressor with a role in immunity [PMID:16260620].","teleology":[{"year":2000,"claim":"Established that DCLRE1A has a direct, conserved role in interstrand crosslink repair rather than merely correlating with crosslink sensitivity.","evidence":"Mouse SNM1 knockout ES cells and mice sensitive to mitomycin C, rescued by human SNM1 cDNA complementation","pmids":["10848582"],"confidence":"High","gaps":["Did not define the biochemical activity underlying repair","Did not place SNM1 relative to other ICL repair pathways"]},{"year":2002,"claim":"Connected DCLRE1A to damage-response foci and a candidate protein partner, framing it as part of an organized DNA damage response.","evidence":"Immunofluorescence showing IR/crosslink-induced foci, co-IP with 53BP1, colocalization with Mre11, focus-formation domain mapping","pmids":["12446782"],"confidence":"High","gaps":["Functional consequence of the 53BP1 interaction not established","No catalytic activity demonstrated"]},{"year":2004,"claim":"Revealed a cell-cycle role distinct from DNA repair, linking DCLRE1A to mitotic checkpoint control via the APC.","evidence":"Snm1-deficient MEFs with mitotic checkpoint defects, co-IP of Snm1 and 53BP1 with APC/cyclosome components","pmids":["15542852"],"confidence":"High","gaps":["Mechanism by which Snm1 targets the APC unresolved","Relationship between nuclease activity and checkpoint role unclear"]},{"year":2007,"claim":"Defined the core biochemical activity: DCLRE1A is a metallo-β-lactamase-dependent 5'-exonuclease and a functional homolog of yeast Pso2.","evidence":"Recombinant protein exonuclease assays, active-site aspartate mutagenesis, substrate requirement analysis, yeast pso2 complementation across multiple phenotypes","pmids":["17804464","18006388"],"confidence":"High","gaps":["How a 5'-exonuclease processes a crosslinked duplex not explained","Substrate engagement at ICLs not directly tested"]},{"year":2008,"claim":"Placed DCLRE1A in an ICL repair pathway operating in parallel to, and genetically separable from, the Fanconi anemia pathway.","evidence":"siRNA depletion in human fibroblasts, additive MMC sensitivity with FA cells, intact FANCD2 mono-ubiquitination","pmids":["18180189"],"confidence":"High","gaps":["Molecular branch point between the two pathways not defined","Order of action relative to incision/recruitment unknown"]},{"year":2005,"claim":"Demonstrated an organism-level consequence of DCLRE1A loss as a tumor suppressor with immune functions.","evidence":"Snm1 knockout mice with accelerated tumorigenesis and infection susceptibility, Trp53 double-knockout epistasis, immune profiling","pmids":["16260620"],"confidence":"High","gaps":["Mechanistic basis for tumor suppression not linked to specific nuclease substrate","Immune phenotype mechanism unresolved"]},{"year":2011,"claim":"Expanded the catalytic repertoire of the family to include structure-specific endonuclease/hairpin-opening activity needed in vivo.","evidence":"In vitro nuclease assays on multiple substrate structures and in vivo hairpin-end break repair assay in yeast Pso2","pmids":["22102580"],"confidence":"High","gaps":["Hairpin-opening activity shown for yeast Pso2, human SNM1A direct confirmation absent","Structural basis of endo- vs exonuclease switching not defined here"]},{"year":2021,"claim":"Provided a structural rationale for substrate selectivity and endo/exo activity through a 5'-phosphate binding pocket.","evidence":"X-ray product-state structure of SNM1B/Apollo with bound nucleotides, pocket mutagenesis, nuclease assays on modified substrates","pmids":["34387694"],"confidence":"Medium","gaps":["Direct structure is of SNM1B with inference to SNM1A","No SNM1A-specific structure with ICL substrate"]},{"year":2020,"claim":"Identified a helicase partner that stimulates DCLRE1A nuclease activity to enable translesion processing through ICLs.","evidence":"Genetic epistasis, gel-based and smFRET nuclease assays, domain-mapped interaction of Hrq1 (RecQ4) with Pso2","pmids":["32371399"],"confidence":"High","gaps":["Shown in yeast; human SNM1A/RecQ4 stimulation not directly demonstrated","In vivo contribution of stimulation to repair outcome unquantified"]},{"year":2022,"claim":"Established dual nuclear/mitochondrial targeting under competitive control of MTS and NLS signals, extending DCLRE1A function to mitochondria.","evidence":"Subcellular fractionation, imaging, and systematic mutagenesis of MTS/NLS in yeast Pso2","pmids":["35482533"],"confidence":"High","gaps":["Mitochondrial substrate/function not defined","Conservation of dual targeting in human SNM1A not shown"]},{"year":2023,"claim":"Showed SUMOylation regulates damage-dependent mitochondrial partitioning of the nuclease, coupling a PTM to organelle-specific genome protection.","evidence":"In vivo SUMOylation assays, K97R/K575R mutants, E3 ligase genetics, mitochondrial DNA damage NGS in yeast Pso2","pmids":["37649278"],"confidence":"High","gaps":["Agent specificity (MMS vs ICL) mechanism unexplained","Human SNM1A SUMOylation not demonstrated"]},{"year":2024,"claim":"Identified CSB as a direct recruiter and activator of SNM1A at ICLs, defining a mechanism for damage-site engagement and resection enhancement.","evidence":"Domain-level interaction mapping (CSB winged-helix to SNM1A nuclease core), in vitro ICL resection assays, single-molecule studies (preprint)","pmids":["bio_10.1101_2024.09.05.611390"],"confidence":"Medium","gaps":["Preprint, not yet peer-reviewed","Cellular requirement of CSB for SNM1A recruitment not confirmed in vivo"]},{"year":2025,"claim":"Implicated DCLRE1A as an effector of repeat instability outcomes through interactions with SLX4 and POLI at nuclease-generated structures.","evidence":"Genome-wide CRISPRi screen, DNA binding assays, co-IP/interaction assays, editing outcome analysis (preprint)","pmids":["bio_10.1101_2025.11.18.689026"],"confidence":"Medium","gaps":["Preprint, not yet peer-reviewed","Direct nature and stoichiometry of SLX4/POLI interactions not fully resolved"]},{"year":null,"claim":"How human DCLRE1A coordinates its exonuclease and endonuclease activities, partner recruitment, and dual organelle targeting into a unified ICL repair mechanism distinct from the FA pathway remains unresolved.","evidence":"No single study integrates the human enzyme's catalysis, recruitment partners, and localization regulation","pmids":[],"confidence":"Low","gaps":["No human SNM1A structure bound to an ICL substrate","In vivo human confirmation of mitochondrial targeting and SUMO regulation absent","Mechanistic link between nuclease activity and mitotic checkpoint function unestablished"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140097","term_label":"catalytic activity, acting on DNA","supporting_discovery_ids":[4,5,8,9]},{"term_id":"GO:0016787","term_label":"hydrolase activity","supporting_discovery_ids":[5,8]},{"term_id":"GO:0003677","term_label":"DNA binding","supporting_discovery_ids":[14,15]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[0,1,11]},{"term_id":"GO:0005739","term_label":"mitochondrion","supporting_discovery_ids":[11,12]}],"pathway":[{"term_id":"R-HSA-73894","term_label":"DNA Repair","supporting_discovery_ids":[0,4,6]},{"term_id":"R-HSA-1640170","term_label":"Cell Cycle","supporting_discovery_ids":[3]}],"complexes":[],"partners":["TP53BP1","ERCC6","SLX4","POLI"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q6PJP8","full_name":"DNA cross-link repair 1A protein","aliases":["Beta-lactamase DCLRE1A","SNM1 homolog A","hSNM1","hSNM1A"],"length_aa":1040,"mass_kda":116.4,"function":"May be required for DNA interstrand cross-link repair. Also required for checkpoint mediated cell cycle arrest in early prophase in response to mitotic spindle poisons. Possesses beta-lactamase activity, catalyzing the hydrolysis of penicillin G and nitrocefin (PubMed:31434986). Exhibits no activity towards other beta-lactam antibiotic classes including cephalosporins (cefotaxime) and carbapenems (imipenem) (PubMed:31434986)","subcellular_location":"Nucleus","url":"https://www.uniprot.org/uniprotkb/Q6PJP8/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/DCLRE1A","classification":"Not Classified","n_dependent_lines":2,"n_total_lines":1208,"dependency_fraction":0.0016556291390728477},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"PCNA","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/DCLRE1A","total_profiled":1310},"omim":[{"mim_id":"609683","title":"DNA CROSS-LINK REPAIR PROTEIN 1B; DCLRE1B","url":"https://www.omim.org/entry/609683"},{"mim_id":"609682","title":"DNA CROSS-LINK REPAIR PROTEIN 1A; DCLRE1A","url":"https://www.omim.org/entry/609682"},{"mim_id":"605367","title":"ELAC RIBONUCLEASE Z 2; ELAC2","url":"https://www.omim.org/entry/605367"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Nucleoplasm","reliability":"Supported"},{"location":"Nucleoli fibrillar center","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/DCLRE1A"},"hgnc":{"alias_symbol":["SNM1","PSO2","KIAA0086","hSNM1"],"prev_symbol":[]},"alphafold":{"accession":"Q6PJP8","domains":[{"cath_id":"-","chopping":"130-177","consensus_level":"high","plddt":85.7444,"start":130,"end":177},{"cath_id":"3.60.15.10","chopping":"704-846_1003-1039","consensus_level":"high","plddt":97.6959,"start":704,"end":1039},{"cath_id":"3.40.50.12650","chopping":"852-992","consensus_level":"high","plddt":94.9262,"start":852,"end":992}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q6PJP8","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q6PJP8-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q6PJP8-F1-predicted_aligned_error_v6.png","plddt_mean":57.88},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=DCLRE1A","jax_strain_url":"https://www.jax.org/strain/search?query=DCLRE1A"},"sequence":{"accession":"Q6PJP8","fasta_url":"https://rest.uniprot.org/uniprotkb/Q6PJP8.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q6PJP8/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q6PJP8"}},"corpus_meta":[{"pmid":"12055248","id":"PMC_12055248","title":"A founder mutation in Artemis, an SNM1-like protein, causes SCID in Athabascan-speaking Native Americans.","date":"2002","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/12055248","citation_count":130,"is_preprint":false},{"pmid":"10848582","id":"PMC_10848582","title":"Disruption of mouse SNM1 causes increased sensitivity to the DNA interstrand cross-linking agent mitomycin C.","date":"2000","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/10848582","citation_count":110,"is_preprint":false},{"pmid":"15743825","id":"PMC_15743825","title":"DNA interstrand cross-link repair in the Saccharomyces cerevisiae cell cycle: overlapping roles for PSO2 (SNM1) with MutS factors and EXO1 during S phase.","date":"2005","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/15743825","citation_count":64,"is_preprint":false},{"pmid":"15590324","id":"PMC_15590324","title":"The yeast Snm1 protein is a DNA 5'-exonuclease.","date":"2005","source":"DNA repair","url":"https://pubmed.ncbi.nlm.nih.gov/15590324","citation_count":60,"is_preprint":false},{"pmid":"12509272","id":"PMC_12509272","title":"The beta-lactamase motif in Snm1 is required for repair of DNA double-strand breaks caused by interstrand crosslinks in S. cerevisiae.","date":"2003","source":"DNA repair","url":"https://pubmed.ncbi.nlm.nih.gov/12509272","citation_count":52,"is_preprint":false},{"pmid":"18006388","id":"PMC_18006388","title":"Human SNM1A suppresses the DNA repair defects of yeast pso2 mutants.","date":"2007","source":"DNA repair","url":"https://pubmed.ncbi.nlm.nih.gov/18006388","citation_count":50,"is_preprint":false},{"pmid":"8628215","id":"PMC_8628215","title":"Regulation of SNM1, an inducible Saccharomyces cerevisiae gene required for repair of DNA cross-links.","date":"1996","source":"Molecular & general genetics : 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A ~220 amino acid region of hSNM1 is sufficient for focus formation when attached to a nuclear localization signal.\",\n      \"method\": \"Indirect immunofluorescence, coimmunoprecipitation, domain mapping with nuclear localization signal constructs\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal coimmunoprecipitation plus direct localization imaging with functional domain mapping, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"12446782\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"hSNM1 translation is mediated by an internal ribosome entry site (IRES) in the 5' UTR that generally suppresses translation but upregulates it during mitosis, suggesting a cell-cycle-regulated mitotic function.\",\n      \"method\": \"Bicistronic construct assays to demonstrate IRES activity, cell-cycle synchronization\",\n      \"journal\": \"DNA repair\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — bicistronic reporter assay plus cell-cycle analysis, single lab\",\n      \"pmids\": [\"12509242\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Mammalian SNM1 functions in an early mitotic stress checkpoint distinct from the spindle assembly checkpoint; Snm1-deficient mouse embryonic fibroblasts exposed to spindle poisons show elevated micronucleus formation, decreased mitotic delay, failure to arrest prior to chromosome condensation, supernumerary centrosomes, and decreased viability. Both Snm1 and 53BP1 coimmunoprecipitate with components of the anaphase-promoting complex (APC/cyclosome), suggesting Snm1 negatively targets the APC before chromosome condensation.\",\n      \"method\": \"Snm1-deficient MEFs, spindle poison treatment, micronucleus assay, coimmunoprecipitation with APC components\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean KO with defined cellular phenotypes plus coimmunoprecipitation identifying APC interaction, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"15542852\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Recombinant hSNM1A (DCLRE1A) is a 5'-exonuclease; ectopic expression of hSNM1A (but not SNM1B/Apollo or Artemis) suppresses yeast pso2 mutant sensitivity to crosslinking agents, rescues the DSB repair defect during cross-link processing, and partially rescues spontaneous intrachromosomal recombination defects, establishing hSNM1A as a functional homolog of yeast Pso2.\",\n      \"method\": \"Recombinant protein exonuclease assay, yeast complementation (suppression of pso2 sensitivity), DSB repair assay, intrachromosomal recombination assay\",\n      \"journal\": \"DNA repair\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro exonuclease assay plus genetic complementation across multiple phenotypes, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"18006388\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"hSNM1 (DCLRE1A) protein is a single-strand 5'-exonuclease that utilizes either DNA or RNA substrates, requires a 5'-phosphate moiety, shows very little activity on double-strand substrates, functions as a monomer, and requires the conserved beta-lactamase domain for activity (site-directed mutagenesis of a conserved aspartate inactivates the exonuclease).\",\n      \"method\": \"Recombinant protein overproduction in insect cells, in vitro exonuclease assays, site-directed mutagenesis\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro biochemical reconstitution plus active-site mutagenesis in a single rigorous study\",\n      \"pmids\": [\"17804464\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"siRNA depletion of hSNM1 in human fibroblasts increases sensitivity to mitomycin C (ICL agent) as measured by cell survival and chromosome radial formation, and this sensitivity is additive with that of Fanconi anemia (FA) cells. Depletion of hSNM1 does not disturb FANCD2 mono-ubiquitination, indicating hSNM1 acts in a pathway parallel to and distinct from the FA pathway for ICL repair.\",\n      \"method\": \"siRNA depletion, cell survival assay, chromosome radial formation assay, FANCD2 ubiquitination western blot, epistasis with FA cell lines\",\n      \"journal\": \"Molecular genetics and metabolism\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean siRNA KD with multiple phenotypic readouts and pathway epistasis analysis, single lab\",\n      \"pmids\": [\"18180189\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Snm1-deficient mice exhibit accelerated tumorigenesis and susceptibility to bacterial infections, and crossing with Trp53 null mice increases mortality and restricts tumor types to lymphomas. Snm1 functions as a tumor suppressor in mice and has a role in immunity, distinct from T- and B-cell development or immunoglobulin class switching defects.\",\n      \"method\": \"Snm1 knockout mice, survival analysis, tumor pathology, Trp53 double knockout epistasis, immune cell profiling\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean KO mouse with defined phenotypic readouts and genetic epistasis with Trp53, single lab with multiple analyses\",\n      \"pmids\": [\"16260620\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Pso2 (yeast ortholog of SNM1A/DCLRE1A) is a structure-specific DNA hairpin opening endonuclease in addition to its known 5'-exonuclease activity; this hairpin-opening activity is required in vivo for repair of chromosomal breaks with closed hairpin ends.\",\n      \"method\": \"In vitro nuclease assays on multiple DNA substrate structures, in vivo genetic assay for hairpin-end chromosomal break repair in yeast\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro biochemical reconstitution with multiple substrates plus in vivo genetic validation, single lab with orthogonal methods\",\n      \"pmids\": [\"22102580\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"The Hrq1 helicase (RecQ4 subfamily) physically interacts with Pso2 (yeast ortholog of SNM1A/DCLRE1A) through their N-terminal domains and stimulates Pso2 nuclease activity, including translesion nuclease activity through site-specific ICLs in vitro; this stimulation requires Hrq1 catalytic activity and is specific to eukaryotic RecQ4 subfamily helicases.\",\n      \"method\": \"Genetic epistasis, in vitro nuclease assays (gel-based and smFRET), biochemical interaction mapping, domain analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution with site-specific ICL substrates, smFRET biophysical analysis, and genetic validation, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"32371399\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"A structure of SNM1B/Apollo with two nucleotides bound to its active site reveals a 5' phosphate binding pocket that is important for catalysis and is a key determinant of endo- versus exonuclease activity across the SNM1 family including SNM1A; base modifications planar to the nucleobase are accommodated by the open active site architecture, while axial lesions are not well tolerated.\",\n      \"method\": \"X-ray crystallography (product-state structure), mutagenesis of phosphate-binding pocket residues, in vitro nuclease assays on modified substrates\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — crystal structure plus mutagenesis, but direct structural work is on SNM1B with inferences extended to SNM1A family; primary focus is SNM1B\",\n      \"pmids\": [\"34387694\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Yeast Pso2 (ortholog of DCLRE1A/SNM1A) is dual-localized to both the nucleus and mitochondria; it contains one mitochondrial targeting sequence (MTS) and two nuclear localization signals (NLS1 and NLS2), with MTS essential for mitochondrial import and either NLS sufficient for nuclear import. Genotoxic agents enhance mitochondrial abundance of Pso2. Ablation of MTS abrogates mitochondrial import and raises nuclear levels, while disruption of both NLS motifs blocks nuclear import and enhances mitochondrial translocation, establishing competitive regulation between MTS and NLS.\",\n      \"method\": \"Subcellular fractionation, fluorescence imaging, mutational analysis of MTS and NLS sequences, in vitro and in vivo localization assays\",\n      \"journal\": \"G3 (Bethesda, Md.)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal localization methods with systematic mutagenesis of targeting sequences, single lab\",\n      \"pmids\": [\"35482533\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Yeast Pso2 undergoes SUMOylation on residues K97 and K575 (catalyzed by Siz1 and Siz2 SUMO E3 ligases, with Siz1 dominant) specifically in response to methyl methanesulfonate (MMS) but not ICL-forming agents; SUMOylation markedly increases Pso2 abundance in mitochondria without affecting nuclear translocation, and SUMOylation-defective mutants (K97R/K575R) fail to translocate to mitochondria after MMS treatment and fail to suppress MMS-induced mitochondrial DNA damage.\",\n      \"method\": \"In vivo SUMOylation assays, site-directed mutagenesis of SUMO consensus sites, subcellular fractionation, genetic analysis of SUMO E3 ligase mutants, next-generation sequencing of mitochondrial DNA damage\",\n      \"journal\": \"Molecular microbiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal methods (mutagenesis, fractionation, NGS), identification of writer enzymes, single lab\",\n      \"pmids\": [\"37649278\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Pso2 (yeast ortholog of DCLRE1A) is phosphorylated by the Sak1 kinase in vitro, coimmunoprecipitates with Sak1 after DNA damage (8-MOP+UVA treatment), and Sak1 interacts with the C-terminal β-CASP domain of Pso2 in two-hybrid assays; epistasis analysis shows SAK1 and PSO2 act in the same ICL repair pathway, while PSO2 and RAD52/RAD50/XRS2 act epistatically, and PSO2 and MRE11 act in distinct repair pathways on the same substrate.\",\n      \"method\": \"Yeast two-hybrid screen, in vitro kinase assay, coimmunoprecipitation, genetic epistasis with DNA damaging agents\",\n      \"journal\": \"Journal of photochemistry and photobiology. B, Biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vitro kinase assay, reciprocal co-IP, and genetic epistasis, single lab\",\n      \"pmids\": [\"24362320\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"DCLRE1A (human SNM1A) was identified via CRISPRi screen as a key effector of CAG repeat contraction following Cas12a-induced staggered cuts within repeat tracts; DCLRE1A recognizes and binds structures generated by Cas12a, interacts with SLX4 to promote pure contractions, and interacts with POLI to generate inverted repeats via template switching mechanisms.\",\n      \"method\": \"CRISPRi genome-wide screen, DNA binding assays, co-immunoprecipitation/interaction assays, editing outcome analysis\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — CRISPRi screen plus binding and interaction assays, preprint not yet peer-reviewed\",\n      \"pmids\": [\"bio_10.1101_2025.11.18.689026\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"CSB (Cockayne Syndrome B/ERCC6) directly interacts with SNM1A (DCLRE1A) through a specific interaction between the winged-helix domain of CSB and the nuclease core of SNM1A; CSB enhances SNM1A resection through ICLs, increases SNM1A affinity for damaged DNA substrates, and alters substrate conformation to enhance ICL processing. CSB was observed preferentially as a dimer when colocalized with SNM1A at ICLs.\",\n      \"method\": \"Biochemical interaction mapping (domain-level), in vitro nuclease resection assays through ICLs, single-molecule studies on site-specific ICL substrates\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution with site-specific ICLs and single-molecule analysis plus domain-level interaction mapping, preprint not yet peer-reviewed\",\n      \"pmids\": [\"bio_10.1101_2024.09.05.611390\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Overexpression of SNM1 cDNA (human homolog, alias KIAA0086) in CHO cells does not render them more resistant to DNA crosslinking agents (mafosfamide, melphalan, mitomycin C), indicating that overexpression of SNM1 alone is not sufficient to confer ICL resistance in this cellular context.\",\n      \"method\": \"Transfection of human SNM1 cDNA into CHO cells, cell survival assay with crosslinking agents\",\n      \"journal\": \"Anticancer research\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — negative result from single overexpression assay in a heterologous cell system, single lab\",\n      \"pmids\": [\"10470107\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"DCLRE1A (hSNM1A) is a nuclear 5'-exonuclease and structure-specific endonuclease with a metallo-β-lactamase/β-CASP catalytic domain that acts in DNA interstrand crosslink (ICL) repair independently of the Fanconi anemia pathway; it physically associates with 53BP1 and the APC/cyclosome to mediate an early mitotic stress checkpoint, is recruited to ICL damage sites by direct interaction with the CSB winged-helix domain which stimulates its resection activity, undergoes SUMO-regulated dual targeting to the nucleus and mitochondria, interacts with SLX4 and POLI to shape repair outcomes at repetitive DNA sequences, and can be stimulated by RecQ4-family helicases for translesion nuclease activity at ICL lesions.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"DCLRE1A (hSNM1A, the functional homolog of yeast Pso2) is a nuclear 5'-exonuclease that operates in DNA interstrand crosslink (ICL) repair through a pathway parallel to and genetically distinct from the Fanconi anemia pathway [#0, #4, #6]. Its catalytic activity is a single-strand 5'-exonuclease that processes either DNA or RNA, requires a 5'-phosphate, acts on the enzyme as a monomer, and depends on a conserved aspartate in its metallo-\\u03b2-lactamase domain [#5]; the broader SNM1 family combines this exonuclease mode with structure-specific endonuclease activity, including DNA hairpin opening required for repair of breaks with closed hairpin ends [#8]. At ICL lesions DCLRE1A is recruited and stimulated by partner proteins: direct binding of the CSB (ERCC6) winged-helix domain to the SNM1A nuclease core enhances resection through crosslinks and increases affinity for damaged DNA [#15], and RecQ4-family helicases stimulate Pso2 translesion nuclease activity through site-specific ICLs [#9]. Beyond crosslink repair, DCLRE1A localizes to nuclear foci, redistributes after ionizing radiation and crosslinking agents, physically associates with 53BP1, and colocalizes with Mre11 [#1], and together with 53BP1 it co-immunoprecipitates with the anaphase-promoting complex to enforce an early mitotic stress checkpoint distinct from the spindle assembly checkpoint [#3]. The protein additionally shapes repair outcomes at repetitive sequences, recognizing nuclease-generated structures and interacting with SLX4 and POLI [#14], and undergoes dual nuclear/mitochondrial targeting governed by competing localization signals and SUMO modification [#11, #12]. In mice Snm1 functions as a tumor suppressor with a role in immunity [#7].\",\n  \"teleology\": [\n    {\n      \"year\": 2000,\n      \"claim\": \"Established that DCLRE1A has a direct, conserved role in interstrand crosslink repair rather than merely correlating with crosslink sensitivity.\",\n      \"evidence\": \"Mouse SNM1 knockout ES cells and mice sensitive to mitomycin C, rescued by human SNM1 cDNA complementation\",\n      \"pmids\": [\"10848582\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not define the biochemical activity underlying repair\", \"Did not place SNM1 relative to other ICL repair pathways\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Connected DCLRE1A to damage-response foci and a candidate protein partner, framing it as part of an organized DNA damage response.\",\n      \"evidence\": \"Immunofluorescence showing IR/crosslink-induced foci, co-IP with 53BP1, colocalization with Mre11, focus-formation domain mapping\",\n      \"pmids\": [\"12446782\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional consequence of the 53BP1 interaction not established\", \"No catalytic activity demonstrated\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Revealed a cell-cycle role distinct from DNA repair, linking DCLRE1A to mitotic checkpoint control via the APC.\",\n      \"evidence\": \"Snm1-deficient MEFs with mitotic checkpoint defects, co-IP of Snm1 and 53BP1 with APC/cyclosome components\",\n      \"pmids\": [\"15542852\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism by which Snm1 targets the APC unresolved\", \"Relationship between nuclease activity and checkpoint role unclear\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Defined the core biochemical activity: DCLRE1A is a metallo-\\u03b2-lactamase-dependent 5'-exonuclease and a functional homolog of yeast Pso2.\",\n      \"evidence\": \"Recombinant protein exonuclease assays, active-site aspartate mutagenesis, substrate requirement analysis, yeast pso2 complementation across multiple phenotypes\",\n      \"pmids\": [\"17804464\", \"18006388\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How a 5'-exonuclease processes a crosslinked duplex not explained\", \"Substrate engagement at ICLs not directly tested\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Placed DCLRE1A in an ICL repair pathway operating in parallel to, and genetically separable from, the Fanconi anemia pathway.\",\n      \"evidence\": \"siRNA depletion in human fibroblasts, additive MMC sensitivity with FA cells, intact FANCD2 mono-ubiquitination\",\n      \"pmids\": [\"18180189\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular branch point between the two pathways not defined\", \"Order of action relative to incision/recruitment unknown\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Demonstrated an organism-level consequence of DCLRE1A loss as a tumor suppressor with immune functions.\",\n      \"evidence\": \"Snm1 knockout mice with accelerated tumorigenesis and infection susceptibility, Trp53 double-knockout epistasis, immune profiling\",\n      \"pmids\": [\"16260620\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanistic basis for tumor suppression not linked to specific nuclease substrate\", \"Immune phenotype mechanism unresolved\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Expanded the catalytic repertoire of the family to include structure-specific endonuclease/hairpin-opening activity needed in vivo.\",\n      \"evidence\": \"In vitro nuclease assays on multiple substrate structures and in vivo hairpin-end break repair assay in yeast Pso2\",\n      \"pmids\": [\"22102580\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Hairpin-opening activity shown for yeast Pso2, human SNM1A direct confirmation absent\", \"Structural basis of endo- vs exonuclease switching not defined here\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Provided a structural rationale for substrate selectivity and endo/exo activity through a 5'-phosphate binding pocket.\",\n      \"evidence\": \"X-ray product-state structure of SNM1B/Apollo with bound nucleotides, pocket mutagenesis, nuclease assays on modified substrates\",\n      \"pmids\": [\"34387694\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct structure is of SNM1B with inference to SNM1A\", \"No SNM1A-specific structure with ICL substrate\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Identified a helicase partner that stimulates DCLRE1A nuclease activity to enable translesion processing through ICLs.\",\n      \"evidence\": \"Genetic epistasis, gel-based and smFRET nuclease assays, domain-mapped interaction of Hrq1 (RecQ4) with Pso2\",\n      \"pmids\": [\"32371399\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Shown in yeast; human SNM1A/RecQ4 stimulation not directly demonstrated\", \"In vivo contribution of stimulation to repair outcome unquantified\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Established dual nuclear/mitochondrial targeting under competitive control of MTS and NLS signals, extending DCLRE1A function to mitochondria.\",\n      \"evidence\": \"Subcellular fractionation, imaging, and systematic mutagenesis of MTS/NLS in yeast Pso2\",\n      \"pmids\": [\"35482533\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mitochondrial substrate/function not defined\", \"Conservation of dual targeting in human SNM1A not shown\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Showed SUMOylation regulates damage-dependent mitochondrial partitioning of the nuclease, coupling a PTM to organelle-specific genome protection.\",\n      \"evidence\": \"In vivo SUMOylation assays, K97R/K575R mutants, E3 ligase genetics, mitochondrial DNA damage NGS in yeast Pso2\",\n      \"pmids\": [\"37649278\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Agent specificity (MMS vs ICL) mechanism unexplained\", \"Human SNM1A SUMOylation not demonstrated\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Identified CSB as a direct recruiter and activator of SNM1A at ICLs, defining a mechanism for damage-site engagement and resection enhancement.\",\n      \"evidence\": \"Domain-level interaction mapping (CSB winged-helix to SNM1A nuclease core), in vitro ICL resection assays, single-molecule studies (preprint)\",\n      \"pmids\": [\"bio_10.1101_2024.09.05.611390\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Preprint, not yet peer-reviewed\", \"Cellular requirement of CSB for SNM1A recruitment not confirmed in vivo\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Implicated DCLRE1A as an effector of repeat instability outcomes through interactions with SLX4 and POLI at nuclease-generated structures.\",\n      \"evidence\": \"Genome-wide CRISPRi screen, DNA binding assays, co-IP/interaction assays, editing outcome analysis (preprint)\",\n      \"pmids\": [\"bio_10.1101_2025.11.18.689026\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Preprint, not yet peer-reviewed\", \"Direct nature and stoichiometry of SLX4/POLI interactions not fully resolved\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How human DCLRE1A coordinates its exonuclease and endonuclease activities, partner recruitment, and dual organelle targeting into a unified ICL repair mechanism distinct from the FA pathway remains unresolved.\",\n      \"evidence\": \"No single study integrates the human enzyme's catalysis, recruitment partners, and localization regulation\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No human SNM1A structure bound to an ICL substrate\", \"In vivo human confirmation of mitochondrial targeting and SUMO regulation absent\", \"Mechanistic link between nuclease activity and mitotic checkpoint function unestablished\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140097\", \"supporting_discovery_ids\": [4, 5, 8, 9]},\n      {\"term_id\": \"GO:0016787\", \"supporting_discovery_ids\": [5, 8]},\n      {\"term_id\": \"GO:0003677\", \"supporting_discovery_ids\": [14, 15]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [0, 1, 11]},\n      {\"term_id\": \"GO:0005739\", \"supporting_discovery_ids\": [11, 12]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-73894\", \"supporting_discovery_ids\": [0, 4, 6]},\n      {\"term_id\": \"R-HSA-1640170\", \"supporting_discovery_ids\": [3]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"TP53BP1\", \"ERCC6\", \"SLX4\", \"POLI\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}