{"gene":"NRDE2","run_date":"2026-04-29T11:37:57","timeline":{"discoveries":[{"year":2010,"finding":"C. elegans NRDE-2 (ortholog of human NRDE2) associates with the Argonaute protein NRDE-3 within nuclei and is recruited by NRDE-3/siRNA complexes to nascent transcripts targeted by RNAi. NRDE-2 is required for siRNA-mediated silencing of pre-mRNAs 3' to sites of RNAi, for accumulation of RNA Polymerase II at RNAi-targeted genomic loci, and for decreases in RNAP II occupancy and transcriptional activity 3' to RNAi target sites, establishing that NRDE-2 inhibits RNAP II during the elongation phase of transcription.","method":"Genetic screen, co-immunoprecipitation (NRDE-2/NRDE-3 association), ChIP (RNAP II occupancy), genetic loss-of-function with pre-mRNA silencing and RNAP II elongation readouts","journal":"Nature","confidence":"High","confidence_rationale":"Tier 2 — reciprocal Co-IP, ChIP, epistasis; replicated by multiple subsequent studies","pmids":["20543824"],"is_preprint":false},{"year":2011,"finding":"The nuclear RNAi (Nrde) pathway, including NRDE-2, maintains heritable RNAi silencing in C. elegans. The Argonaute NRDE-3 associates with heritable siRNAs and, together with NRDE-1, NRDE-2, and NRDE-4, promotes siRNA expression and H3K9 methylation in progeny of dsRNA-exposed animals, demonstrating that NRDE-2 is required for transgenerational epigenetic silencing.","method":"Genetic epistasis, small RNA sequencing, chromatin immunoprecipitation (H3K9me), loss-of-function mutant analysis","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods (ChIP, small RNA-seq, genetics); replicated across studies","pmids":["22106253"],"is_preprint":false},{"year":2011,"finding":"C. elegans NRDE-2 is required for the association of NRDE-1 with pre-mRNA and chromatin of RNAi-targeted genes, and for siRNA-directed H3K9 methylation at those loci. NRDE-3 and NRDE-2 act upstream of NRDE-1 in the nuclear RNAi pathway linking endogenous siRNAs to chromatin modification.","method":"RNA immunoprecipitation, chromatin immunoprecipitation, genetic epistasis with nrde mutants","journal":"PLoS genetics","confidence":"High","confidence_rationale":"Tier 2 — RIP, ChIP, and epistasis; replicated in multiple labs","pmids":["21901112"],"is_preprint":false},{"year":2019,"finding":"Human NRDE2 forms a 1:1 complex with MTR4 (nuclear exosome cofactor) via a conserved MTR4-interacting domain (MID). NRDE2 localizes predominantly in nuclear speckles, where it inhibits MTR4 recruitment and RNA degradation, and thereby ensures efficient mRNA nuclear export. Structurally, NRDE2 interacts with MTR4's key residues and locks MTR4 in a closed conformation, inhibiting MTR4 interaction with the exosome and with CBC and ZFC3H1. MID deletion causes loss of self-renewal of mouse embryonic stem cells.","method":"Co-immunoprecipitation, structural analysis (biochemical), in vitro binding assays, localization (immunofluorescence), loss-of-function (MID deletion) with mRNA export and stem cell phenotype readouts","journal":"Genes & development","confidence":"High","confidence_rationale":"Tier 1 — structural and biochemical data with mutagenesis and multiple functional readouts in single study","pmids":["30842217"],"is_preprint":false},{"year":2018,"finding":"Human NRDE2 is an essential RNA splicing factor that suppresses intron retention in a subset of pre-mRNAs containing short, GC-rich introns with weak 5' and 3' splice sites. NRDE2 preferentially interacts with U5 snRNP components, the exon junction complex, and the RNA exosome. NRDE2 depletion causes genomic instability, DNA damage, centrosome maturation defects, and mitotic progression defects. NRDE2 directly binds and promotes splicing of CEP131 pre-mRNA, and loss of NRDE2 reduces CEP131 protein, impairing recruitment of γ-tubulin and Aurora Kinase A to spindle poles.","method":"RNA-seq (intron retention), co-immunoprecipitation (U5 snRNP, EJC, exosome), siRNA knockdown, immunofluorescence, flow cytometry (DNA damage), direct RNA binding (CEP131 pre-mRNA)","journal":"RNA (New York, N.Y.)","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods (Co-IP, RNA-seq, KD with specific phenotypes, direct target validation)","pmids":["30538148"],"is_preprint":false},{"year":2018,"finding":"Human NRDE-2 forms a complex with MTR4 and both proteins maintain low DNA double-strand break levels. The NRDE-2/MTR4 complex functions in the DNA damage response independently of R-loop formation, though NRDE-2 and MTR4 can affect R-loop signals at a subset of genes.","method":"Co-immunoprecipitation, mass spectrometry, DNA damage assays (γH2AX), R-loop immunofluorescence (S9.6 antibody), siRNA knockdown","journal":"RNA biology","confidence":"Medium","confidence_rationale":"Tier 2 — reciprocal Co-IP and functional assays, single lab","pmids":["29902117"],"is_preprint":false},{"year":2020,"finding":"C. elegans NRDE-2 physically interacts with the RNA helicase MTR-4, and MTR-4 is recruited to pre-mRNAs undergoing nuclear RNAi in a manner requiring nuclear siRNAs, the nuclear Argonaute HRDE-1, and NRDE-2. MTR-4 is required for nuclear RNAi and co-localizes with NRDE-2 in nuclei. The NRDE-2/MTR-4 interaction is evolutionarily conserved (confirmed in human cells).","method":"Immunoprecipitation-mass spectrometry, co-immunoprecipitation, genetic epistasis, immunofluorescence co-localization","journal":"Genetics","confidence":"High","confidence_rationale":"Tier 2 — IP-MS, reciprocal Co-IP, epistasis, conservation validated; replicated across organisms","pmids":["33055090"],"is_preprint":false},{"year":2021,"finding":"In C. elegans, risiRNA-directed NRDE-2 accumulates in the nucleolus and co-localizes with RNA Polymerase I. risiRNAs direct NRDE proteins to associate with pre-rRNAs and silence pre-rRNA expression. NRDE-2 is required for risiRNA-mediated inhibition of RNA Polymerase I elongation, evidenced by decreased RNAP I occupancy downstream of RNAi-targeted sites.","method":"Immunofluorescence (NRDE-2 nucleolar localization), ChIP (RNAP I occupancy), genetic loss-of-function, forward genetic screen","journal":"Nucleic acids research","confidence":"Medium","confidence_rationale":"Tier 2 — ChIP and localization with functional readout; single lab","pmids":["34365510"],"is_preprint":false},{"year":2019,"finding":"In C. elegans, small RNA-directed chromatin compaction in germ cells requires NRDE-2 (pre-mRNA associated factor), the Argonaute NRDE-3, and the HP1-like protein HPL-2, placing NRDE-2 in the pathway linking nuclear siRNAs to higher-order chromatin organization.","method":"Fluorescence microscopy (chromatin compaction), genetic epistasis with nrde-2, nrde-3, and hpl-2 mutants","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 — genetic epistasis with direct microscopy readout; single lab","pmids":["31227740"],"is_preprint":false},{"year":2023,"finding":"Mouse NRDE2 (and CCDC174) bind directly to U1 snRNA independently of canonical U1 snRNP-specific proteins and are required for the selection and efficient processing of weak 5' splice sites in hundreds of genes in mouse ES cells.","method":"BCLIP-seq (cross-linking immunoprecipitation coupled to high-throughput sequencing), RNA-seq (splicing analysis), genetic knockout, direct U1 snRNA binding assay","journal":"RNA (New York, N.Y.)","confidence":"High","confidence_rationale":"Tier 1 — CLIP-seq with direct RNA binding demonstrated, KO with splicing phenotype, mechanistic detail on U1 snRNA interaction","pmids":["37137667"],"is_preprint":false},{"year":2023,"finding":"Tethering NRDE-2 in C. elegans induces heterochromatin formation and subsequently causes de novo synthesis of HRDE-1 guide RNAs, which then amplify small RNAs that load on downstream Argonautes, establishing NRDE-2 as an upstream trigger of a self-enforcing heterochromatin/small RNA amplification loop.","method":"RNA tethering assay, small RNA sequencing, immunofluorescence, genetic epistasis","journal":"Cell reports","confidence":"Medium","confidence_rationale":"Tier 2 — tethering assay with small RNA-seq and epistasis; single lab","pmids":["37083324"],"is_preprint":false},{"year":2024,"finding":"Human NRDE2 promotes homologous recombination (HR) repair by binding to subunits of casein kinase 2 (CK2) and facilitating assembly and activity of the CK2 holoenzyme, which increases phosphorylation of MDC1 and thereby facilitates HR repair. The NRDE2-p.N377I variant abolishes these functions.","method":"Co-immunoprecipitation (NRDE2-CK2 subunits), kinase activity assay (CK2 holoenzyme), phosphorylation assay (MDC1), HR repair assay, variant functional analysis","journal":"Cell genomics","confidence":"Medium","confidence_rationale":"Tier 2 — Co-IP, kinase assay, phosphorylation assay, and variant dissection; single lab","pmids":["38697125"],"is_preprint":false},{"year":2020,"finding":"Human NRDE2 protects KSHV late viral transcripts from PABPN1- and poly(A) polymerase-mediated RNA decay (PPD) at the proper time of late gene expression, enabling time-dependent evasion of PPD. This places NRDE2 as a factor that can sequester decay factors (MTR4/exosome pathway) to protect specific RNAs from nuclear degradation.","method":"siRNA knockdown of NRDE2, RNA-seq of viral transcripts, functional decay assays in KSHV-infected cells","journal":"Journal of virology","confidence":"Low","confidence_rationale":"Tier 3 — KD with transcript-level readout, no direct binding assay for NRDE2-RNA interaction shown","pmids":["32376621"],"is_preprint":false}],"current_model":"NRDE2 is an evolutionarily conserved nuclear factor that (1) associates with nuclear Argonautes and nascent pre-mRNAs to inhibit RNA Polymerase II (and I) elongation during siRNA-directed co-transcriptional gene silencing, directing H3K9 methylation and heritable epigenetic silencing; (2) forms a 1:1 complex with the RNA helicase MTR4 via a conserved MID domain, locking MTR4 in a closed conformation to negatively regulate nuclear exosome recruitment and RNA degradation in nuclear speckles, ensuring mRNA stability and nuclear export; (3) acts as a non-canonical splicing factor that binds U1 snRNA directly and promotes efficient recognition of weak 5' splice sites in hundreds of pre-mRNAs; and (4) facilitates homologous recombination repair by binding CK2 subunits, promoting CK2 holoenzyme assembly and MDC1 phosphorylation."},"narrative":{"teleology":[{"year":2010,"claim":"Identifying NRDE-2 as a nuclear factor that bridges Argonaute/siRNA complexes to transcription machinery resolved how cytoplasmic RNAi signals silence genes co-transcriptionally by inhibiting RNA Pol II elongation.","evidence":"Genetic screen, Co-IP of NRDE-2/NRDE-3, ChIP of Pol II occupancy, and pre-mRNA silencing assays in C. elegans","pmids":["20543824"],"confidence":"High","gaps":["No structural basis for how NRDE-2 stalls Pol II","Mammalian co-transcriptional silencing role not yet tested"]},{"year":2011,"claim":"Demonstrating that NRDE-2 is required for heritable siRNA expression, H3K9 methylation in progeny, and NRDE-1 chromatin association established its position in a hierarchical pathway linking siRNAs to transgenerational epigenetic silencing.","evidence":"Small RNA-seq, ChIP for H3K9me, RIP, and genetic epistasis in C. elegans nrde mutants","pmids":["22106253","21901112"],"confidence":"High","gaps":["Identity of H3K9 methyltransferase recruited by NRDE pathway unknown","Mechanism of heritable siRNA amplification involving NRDE-2 not defined"]},{"year":2018,"claim":"Discovery that human NRDE2 suppresses intron retention in GC-rich, weakly spliced introns and interacts with U5 snRNP and EJC components revealed a previously unknown mammalian splicing function distinct from the worm silencing role.","evidence":"RNA-seq for intron retention, Co-IP with spliceosome components, siRNA knockdown with DNA damage and mitotic phenotypes in human cells","pmids":["30538148"],"confidence":"High","gaps":["Direct RNA-binding specificity determinants not mapped","Relative contribution of splicing vs. exosome regulation to genomic instability unclear"]},{"year":2018,"claim":"Showing that human NRDE2 forms a complex with MTR4 and that both proteins suppress DNA double-strand breaks linked the MTR4 partnership to genome integrity maintenance.","evidence":"Reciprocal Co-IP, mass spectrometry, γH2AX assays, and R-loop immunofluorescence in human cells","pmids":["29902117"],"confidence":"Medium","gaps":["Mechanism by which NRDE2–MTR4 suppresses DSBs not resolved","R-loop contribution remains ambiguous"]},{"year":2019,"claim":"Structural and biochemical characterization of the NRDE2–MTR4 1:1 complex revealed how NRDE2's MID domain locks MTR4 in a closed conformation, blocking exosome, CBC, and ZFC3H1 interactions and thereby protecting mRNAs from degradation in nuclear speckles.","evidence":"Structural/biochemical analysis, mutagenesis, mRNA export assays, MID-deletion phenotype in mouse ES cells","pmids":["30842217"],"confidence":"High","gaps":["Full atomic-resolution structure of NRDE2–MTR4 complex not reported","How NRDE2 selectivity for specific RNA targets is achieved remains unknown"]},{"year":2019,"claim":"Placing NRDE-2 in the pathway linking nuclear siRNAs to higher-order chromatin compaction in germ cells extended the silencing model from gene-level marks to large-scale chromatin organization.","evidence":"Fluorescence microscopy of chromatin compaction, genetic epistasis with nrde-2, nrde-3, hpl-2 in C. elegans","pmids":["31227740"],"confidence":"Medium","gaps":["Mechanism connecting H3K9me to chromatin compaction via HP1 not biochemically resolved","Quantitative contribution of NRDE-2 vs. other factors unclear"]},{"year":2020,"claim":"Demonstrating that MTR-4 is recruited to pre-mRNAs undergoing nuclear RNAi in a NRDE-2-dependent manner unified the worm silencing and mammalian exosome-regulation functions through a conserved NRDE2–MTR4 interaction.","evidence":"IP-MS, Co-IP, genetic epistasis, immunofluorescence co-localization in C. elegans and human cells","pmids":["33055090"],"confidence":"High","gaps":["Whether MTR4 exosome-recruitment inhibition is part of the worm silencing mechanism is untested","Structural basis of worm NRDE-2/MTR-4 interaction not determined"]},{"year":2021,"claim":"Showing that NRDE-2 accumulates in the nucleolus and inhibits RNA Pol I elongation via risiRNAs extended the co-transcriptional silencing paradigm beyond Pol II to ribosomal RNA transcription.","evidence":"Immunofluorescence of nucleolar NRDE-2, ChIP of Pol I occupancy, genetic loss-of-function in C. elegans","pmids":["34365510"],"confidence":"Medium","gaps":["No biochemical reconstitution of Pol I stalling by NRDE-2","Relevance of Pol I silencing to mammalian NRDE2 unknown"]},{"year":2023,"claim":"Direct binding of NRDE2 to U1 snRNA (independent of canonical U1-specific proteins) and its requirement for weak 5′ splice site selection established the molecular basis for its non-canonical splicing function.","evidence":"BCLIP-seq, RNA-seq splicing analysis, genetic knockout, direct U1 snRNA binding assay in mouse ES cells","pmids":["37137667"],"confidence":"High","gaps":["RNA-binding domain within NRDE2 responsible for U1 recognition not mapped","Whether U1 snRNA binding and MTR4 binding are mutually exclusive is unknown"]},{"year":2023,"claim":"Tethering NRDE-2 to chromatin suffices to trigger heterochromatin formation and de novo small RNA synthesis, establishing NRDE-2 as an upstream trigger of a self-enforcing silencing amplification loop.","evidence":"RNA tethering assay, small RNA-seq, immunofluorescence, genetic epistasis in C. elegans","pmids":["37083324"],"confidence":"Medium","gaps":["Whether NRDE-2 has intrinsic chromatin-remodeling activity or solely scaffolds effectors is unresolved","Mammalian relevance of this amplification loop untested"]},{"year":2024,"claim":"Identifying NRDE2 as a CK2-binding protein that promotes CK2 holoenzyme assembly and MDC1 phosphorylation revealed a new mechanism through which NRDE2 facilitates homologous recombination repair.","evidence":"Co-IP of NRDE2 with CK2 subunits, CK2 kinase assay, MDC1 phosphorylation assay, HR repair assay, NRDE2-p.N377I variant analysis in human cells","pmids":["38697125"],"confidence":"Medium","gaps":["Structural basis of NRDE2–CK2 interaction not determined","Relationship between CK2-mediated HR function and NRDE2's splicing/exosome roles unclear","Not independently replicated"]},{"year":null,"claim":"How NRDE2's multiple functions — co-transcriptional silencing, exosome inhibition via MTR4, U1-dependent splicing, and CK2-mediated HR repair — are coordinated or partitioned across cell types and contexts remains unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No unified structural model of full-length NRDE2 with its multiple partners","Relative physiological importance of each function in mammalian tissues unknown","Whether disease-associated variants selectively impair specific NRDE2 functions is largely unexplored"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0003723","term_label":"RNA binding","supporting_discovery_ids":[4,9]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[3,6,11]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,3,11]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[0,3,4,6]},{"term_id":"GO:0005654","term_label":"nucleoplasm","supporting_discovery_ids":[3,4]},{"term_id":"GO:0005730","term_label":"nucleolus","supporting_discovery_ids":[7]}],"pathway":[{"term_id":"R-HSA-8953854","term_label":"Metabolism of RNA","supporting_discovery_ids":[4,9]},{"term_id":"R-HSA-73894","term_label":"DNA Repair","supporting_discovery_ids":[5,11]},{"term_id":"R-HSA-4839726","term_label":"Chromatin organization","supporting_discovery_ids":[1,2,8,10]}],"complexes":["NRDE2–MTR4 complex"],"partners":["MTR4","NRDE-3","NRDE-1","CSNK2A1","CSNK2B","CCDC174"],"other_free_text":[]},"mechanistic_narrative":"NRDE2 is an evolutionarily conserved nuclear factor that operates at the interface of co-transcriptional gene silencing, RNA processing, and genome maintenance. In C. elegans, NRDE-2 associates with nuclear Argonaute/siRNA complexes on nascent transcripts to inhibit RNA Polymerase II (and Pol I) elongation, direct H3K9 methylation and chromatin compaction, and sustain transgenerational epigenetic silencing through a self-enforcing heterochromatin/small RNA amplification loop [PMID:20543824, PMID:22106253, PMID:34365510, PMID:37083324]. In mammalian cells, NRDE2 forms a 1:1 complex with the RNA helicase MTR4 via a conserved MID domain, locking MTR4 in a closed conformation that inhibits nuclear exosome recruitment and thereby protects mRNAs for efficient nuclear export [PMID:30842217]; independently, NRDE2 binds U1 snRNA directly and promotes recognition of weak 5′ splice sites in hundreds of pre-mRNAs, functioning as a non-canonical splicing factor [PMID:37137667, PMID:30538148]. NRDE2 also facilitates homologous recombination repair by binding CK2 subunits, promoting CK2 holoenzyme assembly and MDC1 phosphorylation [PMID:38697125]."},"prefetch_data":{"uniprot":{"accession":"Q9H7Z3","full_name":"Nuclear exosome regulator NRDE2","aliases":["Protein NRDE2 homolog"],"length_aa":1164,"mass_kda":132.7,"function":"Protein of the nuclear speckles that regulates RNA degradation and export from the nucleus through its interaction with MTREX an essential factor directing various RNAs to exosomal degradation (PubMed:30842217). Changes the conformation of MTREX, precluding its association with the nuclear exosome and interaction with proteins required for its function in RNA exosomal degradation (PubMed:30842217). Negatively regulates, for instance, the degradation of mRNAs and lncRNAs by inhibiting their MTREX-mediated recruitment to nuclear exosome (PubMed:30842217). By preventing the degradation of RNAs in the nucleus, it promotes their export to the cytoplasm (PubMed:30842217). U5 snRNP-associated RNA splicing factor which is required for efficient splicing of CEP131 pre-mRNA and plays an important role in centrosome maturation, integrity and function during mitosis (PubMed:30538148). Suppresses intron retention in a subset of pre-mRNAs containing short, GC-rich introns with relatively weak 5' and 3' splice sites (PubMed:30538148). Plays a role in DNA damage response (PubMed:29902117)","subcellular_location":"Nucleus speckle; Nucleus, nucleolus; Nucleus, nucleoplasm; Nucleus","url":"https://www.uniprot.org/uniprotkb/Q9H7Z3/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/NRDE2","classification":"Common Essential","n_dependent_lines":1202,"n_total_lines":1208,"dependency_fraction":0.9950331125827815},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"ATP6AP2","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/NRDE2","total_profiled":1310},"omim":[{"mim_id":"618631","title":"NRDE2, NECESSARY FOR RNA INTERFERENCE, DOMAIN CONTAINING; NRDE2","url":"https://www.omim.org/entry/618631"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Nucleoplasm","reliability":"Supported"},{"location":"Mitochondria","reliability":"Supported"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in many","driving_tissues":[],"url":"https://www.proteinatlas.org/search/NRDE2"},"hgnc":{"alias_symbol":["FLJ14051"],"prev_symbol":["C14orf102"]},"alphafold":{"accession":"Q9H7Z3","domains":[],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9H7Z3","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9H7Z3-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9H7Z3-F1-predicted_aligned_error_v6.png","plddt_mean":72.06},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=NRDE2","jax_strain_url":"https://www.jax.org/strain/search?query=NRDE2"},"sequence":{"accession":"Q9H7Z3","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9H7Z3.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9H7Z3/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9H7Z3"}},"corpus_meta":[{"pmid":"20543824","id":"PMC_20543824","title":"Small regulatory RNAs inhibit RNA polymerase II during the elongation phase of transcription.","date":"2010","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/20543824","citation_count":235,"is_preprint":false},{"pmid":"22106253","id":"PMC_22106253","title":"Nuclear RNAi maintains heritable gene silencing in Caenorhabditis elegans.","date":"2011","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/22106253","citation_count":153,"is_preprint":false},{"pmid":"21901112","id":"PMC_21901112","title":"A pre-mRNA-associating factor links endogenous siRNAs to chromatin regulation.","date":"2011","source":"PLoS genetics","url":"https://pubmed.ncbi.nlm.nih.gov/21901112","citation_count":116,"is_preprint":false},{"pmid":"30842217","id":"PMC_30842217","title":"NRDE2 negatively regulates exosome functions by inhibiting MTR4 recruitment and exosome interaction.","date":"2019","source":"Genes & development","url":"https://pubmed.ncbi.nlm.nih.gov/30842217","citation_count":44,"is_preprint":false},{"pmid":"25258416","id":"PMC_25258416","title":"Caenorhabditis elegans RSD-2 and RSD-6 promote germ cell immortality by maintaining small interfering RNA populations.","date":"2014","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/25258416","citation_count":34,"is_preprint":false},{"pmid":"34365510","id":"PMC_34365510","title":"Antisense ribosomal siRNAs inhibit RNA polymerase I-directed transcription in C. elegans.","date":"2021","source":"Nucleic acids research","url":"https://pubmed.ncbi.nlm.nih.gov/34365510","citation_count":25,"is_preprint":false},{"pmid":"31227740","id":"PMC_31227740","title":"Chromatin Compaction by Small RNAs and the Nuclear RNAi Machinery in C. elegans.","date":"2019","source":"Scientific 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in the Bacillus anthracis nrdE group I intron.","date":"2007","source":"Journal of bacteriology","url":"https://pubmed.ncbi.nlm.nih.gov/17496101","citation_count":12,"is_preprint":false},{"pmid":"33055090","id":"PMC_33055090","title":"A Conserved NRDE-2/MTR-4 Complex Mediates Nuclear RNAi in Caenorhabditis elegans.","date":"2020","source":"Genetics","url":"https://pubmed.ncbi.nlm.nih.gov/33055090","citation_count":12,"is_preprint":false},{"pmid":"31219728","id":"PMC_31219728","title":"Identification of proteins associated with splicing factors Ntr1, Ntr2, Brr2 and Gpl1 in the fission yeast Schizosaccharomyces pombe.","date":"2019","source":"Cell cycle (Georgetown, Tex.)","url":"https://pubmed.ncbi.nlm.nih.gov/31219728","citation_count":11,"is_preprint":false},{"pmid":"38697125","id":"PMC_38697125","title":"NRDE2 deficiency impairs homologous recombination repair and sensitizes hepatocellular carcinoma to PARP inhibitors.","date":"2024","source":"Cell 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biology","url":"https://pubmed.ncbi.nlm.nih.gov/37216322","citation_count":0,"is_preprint":false},{"pmid":"38723605","id":"PMC_38723605","title":"Rare-variant association study unveils the Achilles' heel for HCC.","date":"2024","source":"Cell genomics","url":"https://pubmed.ncbi.nlm.nih.gov/38723605","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":10311,"output_tokens":3617,"usd":0.042594},"stage2":{"model":"claude-opus-4-6","input_tokens":6986,"output_tokens":3056,"usd":0.166995},"total_usd":0.209589,"stage1_batch_id":"msgbatch_012ZiiCUBfB62NCTQd4Bk1Jo","stage2_batch_id":"msgbatch_01Xuqq9aUHoQouS7UVGZNStZ","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2010,\n      \"finding\": \"C. elegans NRDE-2 (ortholog of human NRDE2) associates with the Argonaute protein NRDE-3 within nuclei and is recruited by NRDE-3/siRNA complexes to nascent transcripts targeted by RNAi. NRDE-2 is required for siRNA-mediated silencing of pre-mRNAs 3' to sites of RNAi, for accumulation of RNA Polymerase II at RNAi-targeted genomic loci, and for decreases in RNAP II occupancy and transcriptional activity 3' to RNAi target sites, establishing that NRDE-2 inhibits RNAP II during the elongation phase of transcription.\",\n      \"method\": \"Genetic screen, co-immunoprecipitation (NRDE-2/NRDE-3 association), ChIP (RNAP II occupancy), genetic loss-of-function with pre-mRNA silencing and RNAP II elongation readouts\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal Co-IP, ChIP, epistasis; replicated by multiple subsequent studies\",\n      \"pmids\": [\"20543824\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"The nuclear RNAi (Nrde) pathway, including NRDE-2, maintains heritable RNAi silencing in C. elegans. The Argonaute NRDE-3 associates with heritable siRNAs and, together with NRDE-1, NRDE-2, and NRDE-4, promotes siRNA expression and H3K9 methylation in progeny of dsRNA-exposed animals, demonstrating that NRDE-2 is required for transgenerational epigenetic silencing.\",\n      \"method\": \"Genetic epistasis, small RNA sequencing, chromatin immunoprecipitation (H3K9me), loss-of-function mutant analysis\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (ChIP, small RNA-seq, genetics); replicated across studies\",\n      \"pmids\": [\"22106253\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"C. elegans NRDE-2 is required for the association of NRDE-1 with pre-mRNA and chromatin of RNAi-targeted genes, and for siRNA-directed H3K9 methylation at those loci. NRDE-3 and NRDE-2 act upstream of NRDE-1 in the nuclear RNAi pathway linking endogenous siRNAs to chromatin modification.\",\n      \"method\": \"RNA immunoprecipitation, chromatin immunoprecipitation, genetic epistasis with nrde mutants\",\n      \"journal\": \"PLoS genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — RIP, ChIP, and epistasis; replicated in multiple labs\",\n      \"pmids\": [\"21901112\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Human NRDE2 forms a 1:1 complex with MTR4 (nuclear exosome cofactor) via a conserved MTR4-interacting domain (MID). NRDE2 localizes predominantly in nuclear speckles, where it inhibits MTR4 recruitment and RNA degradation, and thereby ensures efficient mRNA nuclear export. Structurally, NRDE2 interacts with MTR4's key residues and locks MTR4 in a closed conformation, inhibiting MTR4 interaction with the exosome and with CBC and ZFC3H1. MID deletion causes loss of self-renewal of mouse embryonic stem cells.\",\n      \"method\": \"Co-immunoprecipitation, structural analysis (biochemical), in vitro binding assays, localization (immunofluorescence), loss-of-function (MID deletion) with mRNA export and stem cell phenotype readouts\",\n      \"journal\": \"Genes & development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — structural and biochemical data with mutagenesis and multiple functional readouts in single study\",\n      \"pmids\": [\"30842217\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Human NRDE2 is an essential RNA splicing factor that suppresses intron retention in a subset of pre-mRNAs containing short, GC-rich introns with weak 5' and 3' splice sites. NRDE2 preferentially interacts with U5 snRNP components, the exon junction complex, and the RNA exosome. NRDE2 depletion causes genomic instability, DNA damage, centrosome maturation defects, and mitotic progression defects. NRDE2 directly binds and promotes splicing of CEP131 pre-mRNA, and loss of NRDE2 reduces CEP131 protein, impairing recruitment of γ-tubulin and Aurora Kinase A to spindle poles.\",\n      \"method\": \"RNA-seq (intron retention), co-immunoprecipitation (U5 snRNP, EJC, exosome), siRNA knockdown, immunofluorescence, flow cytometry (DNA damage), direct RNA binding (CEP131 pre-mRNA)\",\n      \"journal\": \"RNA (New York, N.Y.)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (Co-IP, RNA-seq, KD with specific phenotypes, direct target validation)\",\n      \"pmids\": [\"30538148\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Human NRDE-2 forms a complex with MTR4 and both proteins maintain low DNA double-strand break levels. The NRDE-2/MTR4 complex functions in the DNA damage response independently of R-loop formation, though NRDE-2 and MTR4 can affect R-loop signals at a subset of genes.\",\n      \"method\": \"Co-immunoprecipitation, mass spectrometry, DNA damage assays (γH2AX), R-loop immunofluorescence (S9.6 antibody), siRNA knockdown\",\n      \"journal\": \"RNA biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal Co-IP and functional assays, single lab\",\n      \"pmids\": [\"29902117\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"C. elegans NRDE-2 physically interacts with the RNA helicase MTR-4, and MTR-4 is recruited to pre-mRNAs undergoing nuclear RNAi in a manner requiring nuclear siRNAs, the nuclear Argonaute HRDE-1, and NRDE-2. MTR-4 is required for nuclear RNAi and co-localizes with NRDE-2 in nuclei. The NRDE-2/MTR-4 interaction is evolutionarily conserved (confirmed in human cells).\",\n      \"method\": \"Immunoprecipitation-mass spectrometry, co-immunoprecipitation, genetic epistasis, immunofluorescence co-localization\",\n      \"journal\": \"Genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — IP-MS, reciprocal Co-IP, epistasis, conservation validated; replicated across organisms\",\n      \"pmids\": [\"33055090\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"In C. elegans, risiRNA-directed NRDE-2 accumulates in the nucleolus and co-localizes with RNA Polymerase I. risiRNAs direct NRDE proteins to associate with pre-rRNAs and silence pre-rRNA expression. NRDE-2 is required for risiRNA-mediated inhibition of RNA Polymerase I elongation, evidenced by decreased RNAP I occupancy downstream of RNAi-targeted sites.\",\n      \"method\": \"Immunofluorescence (NRDE-2 nucleolar localization), ChIP (RNAP I occupancy), genetic loss-of-function, forward genetic screen\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — ChIP and localization with functional readout; single lab\",\n      \"pmids\": [\"34365510\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"In C. elegans, small RNA-directed chromatin compaction in germ cells requires NRDE-2 (pre-mRNA associated factor), the Argonaute NRDE-3, and the HP1-like protein HPL-2, placing NRDE-2 in the pathway linking nuclear siRNAs to higher-order chromatin organization.\",\n      \"method\": \"Fluorescence microscopy (chromatin compaction), genetic epistasis with nrde-2, nrde-3, and hpl-2 mutants\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — genetic epistasis with direct microscopy readout; single lab\",\n      \"pmids\": [\"31227740\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Mouse NRDE2 (and CCDC174) bind directly to U1 snRNA independently of canonical U1 snRNP-specific proteins and are required for the selection and efficient processing of weak 5' splice sites in hundreds of genes in mouse ES cells.\",\n      \"method\": \"BCLIP-seq (cross-linking immunoprecipitation coupled to high-throughput sequencing), RNA-seq (splicing analysis), genetic knockout, direct U1 snRNA binding assay\",\n      \"journal\": \"RNA (New York, N.Y.)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — CLIP-seq with direct RNA binding demonstrated, KO with splicing phenotype, mechanistic detail on U1 snRNA interaction\",\n      \"pmids\": [\"37137667\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Tethering NRDE-2 in C. elegans induces heterochromatin formation and subsequently causes de novo synthesis of HRDE-1 guide RNAs, which then amplify small RNAs that load on downstream Argonautes, establishing NRDE-2 as an upstream trigger of a self-enforcing heterochromatin/small RNA amplification loop.\",\n      \"method\": \"RNA tethering assay, small RNA sequencing, immunofluorescence, genetic epistasis\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — tethering assay with small RNA-seq and epistasis; single lab\",\n      \"pmids\": [\"37083324\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Human NRDE2 promotes homologous recombination (HR) repair by binding to subunits of casein kinase 2 (CK2) and facilitating assembly and activity of the CK2 holoenzyme, which increases phosphorylation of MDC1 and thereby facilitates HR repair. The NRDE2-p.N377I variant abolishes these functions.\",\n      \"method\": \"Co-immunoprecipitation (NRDE2-CK2 subunits), kinase activity assay (CK2 holoenzyme), phosphorylation assay (MDC1), HR repair assay, variant functional analysis\",\n      \"journal\": \"Cell genomics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — Co-IP, kinase assay, phosphorylation assay, and variant dissection; single lab\",\n      \"pmids\": [\"38697125\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Human NRDE2 protects KSHV late viral transcripts from PABPN1- and poly(A) polymerase-mediated RNA decay (PPD) at the proper time of late gene expression, enabling time-dependent evasion of PPD. This places NRDE2 as a factor that can sequester decay factors (MTR4/exosome pathway) to protect specific RNAs from nuclear degradation.\",\n      \"method\": \"siRNA knockdown of NRDE2, RNA-seq of viral transcripts, functional decay assays in KSHV-infected cells\",\n      \"journal\": \"Journal of virology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — KD with transcript-level readout, no direct binding assay for NRDE2-RNA interaction shown\",\n      \"pmids\": [\"32376621\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"NRDE2 is an evolutionarily conserved nuclear factor that (1) associates with nuclear Argonautes and nascent pre-mRNAs to inhibit RNA Polymerase II (and I) elongation during siRNA-directed co-transcriptional gene silencing, directing H3K9 methylation and heritable epigenetic silencing; (2) forms a 1:1 complex with the RNA helicase MTR4 via a conserved MID domain, locking MTR4 in a closed conformation to negatively regulate nuclear exosome recruitment and RNA degradation in nuclear speckles, ensuring mRNA stability and nuclear export; (3) acts as a non-canonical splicing factor that binds U1 snRNA directly and promotes efficient recognition of weak 5' splice sites in hundreds of pre-mRNAs; and (4) facilitates homologous recombination repair by binding CK2 subunits, promoting CK2 holoenzyme assembly and MDC1 phosphorylation.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"NRDE2 is an evolutionarily conserved nuclear factor that operates at the interface of co-transcriptional gene silencing, RNA processing, and genome maintenance. In C. elegans, NRDE-2 associates with nuclear Argonaute/siRNA complexes on nascent transcripts to inhibit RNA Polymerase II (and Pol I) elongation, direct H3K9 methylation and chromatin compaction, and sustain transgenerational epigenetic silencing through a self-enforcing heterochromatin/small RNA amplification loop [PMID:20543824, PMID:22106253, PMID:34365510, PMID:37083324]. In mammalian cells, NRDE2 forms a 1:1 complex with the RNA helicase MTR4 via a conserved MID domain, locking MTR4 in a closed conformation that inhibits nuclear exosome recruitment and thereby protects mRNAs for efficient nuclear export [PMID:30842217]; independently, NRDE2 binds U1 snRNA directly and promotes recognition of weak 5′ splice sites in hundreds of pre-mRNAs, functioning as a non-canonical splicing factor [PMID:37137667, PMID:30538148]. NRDE2 also facilitates homologous recombination repair by binding CK2 subunits, promoting CK2 holoenzyme assembly and MDC1 phosphorylation [PMID:38697125].\",\n  \"teleology\": [\n    {\n      \"year\": 2010,\n      \"claim\": \"Identifying NRDE-2 as a nuclear factor that bridges Argonaute/siRNA complexes to transcription machinery resolved how cytoplasmic RNAi signals silence genes co-transcriptionally by inhibiting RNA Pol II elongation.\",\n      \"evidence\": \"Genetic screen, Co-IP of NRDE-2/NRDE-3, ChIP of Pol II occupancy, and pre-mRNA silencing assays in C. elegans\",\n      \"pmids\": [\"20543824\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No structural basis for how NRDE-2 stalls Pol II\", \"Mammalian co-transcriptional silencing role not yet tested\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Demonstrating that NRDE-2 is required for heritable siRNA expression, H3K9 methylation in progeny, and NRDE-1 chromatin association established its position in a hierarchical pathway linking siRNAs to transgenerational epigenetic silencing.\",\n      \"evidence\": \"Small RNA-seq, ChIP for H3K9me, RIP, and genetic epistasis in C. elegans nrde mutants\",\n      \"pmids\": [\"22106253\", \"21901112\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of H3K9 methyltransferase recruited by NRDE pathway unknown\", \"Mechanism of heritable siRNA amplification involving NRDE-2 not defined\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Discovery that human NRDE2 suppresses intron retention in GC-rich, weakly spliced introns and interacts with U5 snRNP and EJC components revealed a previously unknown mammalian splicing function distinct from the worm silencing role.\",\n      \"evidence\": \"RNA-seq for intron retention, Co-IP with spliceosome components, siRNA knockdown with DNA damage and mitotic phenotypes in human cells\",\n      \"pmids\": [\"30538148\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct RNA-binding specificity determinants not mapped\", \"Relative contribution of splicing vs. exosome regulation to genomic instability unclear\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Showing that human NRDE2 forms a complex with MTR4 and that both proteins suppress DNA double-strand breaks linked the MTR4 partnership to genome integrity maintenance.\",\n      \"evidence\": \"Reciprocal Co-IP, mass spectrometry, γH2AX assays, and R-loop immunofluorescence in human cells\",\n      \"pmids\": [\"29902117\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which NRDE2–MTR4 suppresses DSBs not resolved\", \"R-loop contribution remains ambiguous\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Structural and biochemical characterization of the NRDE2–MTR4 1:1 complex revealed how NRDE2's MID domain locks MTR4 in a closed conformation, blocking exosome, CBC, and ZFC3H1 interactions and thereby protecting mRNAs from degradation in nuclear speckles.\",\n      \"evidence\": \"Structural/biochemical analysis, mutagenesis, mRNA export assays, MID-deletion phenotype in mouse ES cells\",\n      \"pmids\": [\"30842217\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Full atomic-resolution structure of NRDE2–MTR4 complex not reported\", \"How NRDE2 selectivity for specific RNA targets is achieved remains unknown\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Placing NRDE-2 in the pathway linking nuclear siRNAs to higher-order chromatin compaction in germ cells extended the silencing model from gene-level marks to large-scale chromatin organization.\",\n      \"evidence\": \"Fluorescence microscopy of chromatin compaction, genetic epistasis with nrde-2, nrde-3, hpl-2 in C. elegans\",\n      \"pmids\": [\"31227740\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism connecting H3K9me to chromatin compaction via HP1 not biochemically resolved\", \"Quantitative contribution of NRDE-2 vs. other factors unclear\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Demonstrating that MTR-4 is recruited to pre-mRNAs undergoing nuclear RNAi in a NRDE-2-dependent manner unified the worm silencing and mammalian exosome-regulation functions through a conserved NRDE2–MTR4 interaction.\",\n      \"evidence\": \"IP-MS, Co-IP, genetic epistasis, immunofluorescence co-localization in C. elegans and human cells\",\n      \"pmids\": [\"33055090\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether MTR4 exosome-recruitment inhibition is part of the worm silencing mechanism is untested\", \"Structural basis of worm NRDE-2/MTR-4 interaction not determined\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Showing that NRDE-2 accumulates in the nucleolus and inhibits RNA Pol I elongation via risiRNAs extended the co-transcriptional silencing paradigm beyond Pol II to ribosomal RNA transcription.\",\n      \"evidence\": \"Immunofluorescence of nucleolar NRDE-2, ChIP of Pol I occupancy, genetic loss-of-function in C. elegans\",\n      \"pmids\": [\"34365510\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No biochemical reconstitution of Pol I stalling by NRDE-2\", \"Relevance of Pol I silencing to mammalian NRDE2 unknown\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Direct binding of NRDE2 to U1 snRNA (independent of canonical U1-specific proteins) and its requirement for weak 5′ splice site selection established the molecular basis for its non-canonical splicing function.\",\n      \"evidence\": \"BCLIP-seq, RNA-seq splicing analysis, genetic knockout, direct U1 snRNA binding assay in mouse ES cells\",\n      \"pmids\": [\"37137667\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"RNA-binding domain within NRDE2 responsible for U1 recognition not mapped\", \"Whether U1 snRNA binding and MTR4 binding are mutually exclusive is unknown\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Tethering NRDE-2 to chromatin suffices to trigger heterochromatin formation and de novo small RNA synthesis, establishing NRDE-2 as an upstream trigger of a self-enforcing silencing amplification loop.\",\n      \"evidence\": \"RNA tethering assay, small RNA-seq, immunofluorescence, genetic epistasis in C. elegans\",\n      \"pmids\": [\"37083324\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether NRDE-2 has intrinsic chromatin-remodeling activity or solely scaffolds effectors is unresolved\", \"Mammalian relevance of this amplification loop untested\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Identifying NRDE2 as a CK2-binding protein that promotes CK2 holoenzyme assembly and MDC1 phosphorylation revealed a new mechanism through which NRDE2 facilitates homologous recombination repair.\",\n      \"evidence\": \"Co-IP of NRDE2 with CK2 subunits, CK2 kinase assay, MDC1 phosphorylation assay, HR repair assay, NRDE2-p.N377I variant analysis in human cells\",\n      \"pmids\": [\"38697125\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Structural basis of NRDE2–CK2 interaction not determined\", \"Relationship between CK2-mediated HR function and NRDE2's splicing/exosome roles unclear\", \"Not independently replicated\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How NRDE2's multiple functions — co-transcriptional silencing, exosome inhibition via MTR4, U1-dependent splicing, and CK2-mediated HR repair — are coordinated or partitioned across cell types and contexts remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No unified structural model of full-length NRDE2 with its multiple partners\", \"Relative physiological importance of each function in mammalian tissues unknown\", \"Whether disease-associated variants selectively impair specific NRDE2 functions is largely unexplored\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0003723\", \"supporting_discovery_ids\": [4, 9]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [3, 6, 11]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 3, 11]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [0, 3, 4, 6]},\n      {\"term_id\": \"GO:0005654\", \"supporting_discovery_ids\": [3, 4]},\n      {\"term_id\": \"GO:0005730\", \"supporting_discovery_ids\": [7]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0074160\", \"supporting_discovery_ids\": [0, 1, 2, 7, 10]},\n      {\"term_id\": \"R-HSA-8953854\", \"supporting_discovery_ids\": [4, 9]},\n      {\"term_id\": \"R-HSA-73894\", \"supporting_discovery_ids\": [5, 11]},\n      {\"term_id\": \"R-HSA-4839726\", \"supporting_discovery_ids\": [1, 2, 8, 10]}\n    ],\n    \"complexes\": [\n      \"NRDE2–MTR4 complex\"\n    ],\n    \"partners\": [\n      \"MTR4\",\n      \"NRDE-3\",\n      \"NRDE-1\",\n      \"CSNK2A1\",\n      \"CSNK2B\",\n      \"CCDC174\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}