{"gene":"NSUN5","run_date":"2026-06-10T05:19:52","timeline":{"discoveries":[{"year":2015,"finding":"Human p120 (NOL1/NSUN5) possesses RNA:m5C-methyltransferase activity and methylates position 2870 in domain V of 25S rRNA, functionally complementing the yeast Nop2p orthologue in a nop2Δ strain. Chimeric protein analysis revealed the importance of the Nop2 N-terminal domain for correct protein localization and cellular function.","method":"RNA bisulfite sequencing, HPLC-MS/MS, functional complementation of nop2Δ yeast, chimeric protein analysis","journal":"PloS one","confidence":"High","confidence_rationale":"Tier 1 / Strong — direct in vitro enzymatic activity assay (bisulfite sequencing + HPLC-MS/MS) combined with functional genetic complementation and domain-swap mutagenesis; multiple orthogonal methods in one study","pmids":["26196125"],"is_preprint":false},{"year":2001,"finding":"NSUN5 (WBSCR20) encodes a novel protein with similarity to p120 (NOL1), a proliferation-associated nucleolar antigen; the gene maps to the Williams-Beuren syndrome deletion region at 7q11.23. A highly similar putative gene, WBSCR20B, flanks the WBS deletion at the telomeric side.","method":"Sequence homology analysis, genomic mapping, expression analysis in tissues","journal":"Cytogenetics and cell genetics","confidence":"Low","confidence_rationale":"Tier 4 / Weak — characterization based on sequence similarity and genomic mapping only; no direct biochemical or functional experiments performed on NSUN5 protein","pmids":["11978965"],"is_preprint":false},{"year":2006,"finding":"p120 (NOL1/NSUN5) expression is directly regulated by G-CSF signaling through STAT3 and STAT5 binding to a site in the first intron of the gene. Overexpression of p120 in G-CSF-induced 32D cells caused loss of lactoferrin expression, a marker of normal neutrophil maturation, indicating that inappropriate p120 expression results in aberrant neutrophil maturation.","method":"cDNA representational difference analysis, Northern blot, transient transfection, oligonucleotide pull-down assay, loss-of-function in STAT3-deficient mouse bone marrow, overexpression with morphological and marker readout","journal":"Journal of leukocyte biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal methods (pull-down, transfection, in vivo knockout model) in a single lab study demonstrating pathway placement and functional consequence","pmids":["16641140"],"is_preprint":false},{"year":2023,"finding":"NSUN5 associates with SLC7A11 mRNA and promotes its m5C methylation, enhancing SLC7A11 protein translation and conferring resistance against ferroptosis in liver cells.","method":"Dot blot (global m5C levels), immunofluorescence co-localization, RNA binding protein immunoprecipitation (RIP)","journal":"Phytomedicine","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — RIP demonstrates direct binding of NSUN5 to SLC7A11 mRNA; functional ferroptosis resistance readout; single lab with two orthogonal binding/localization methods but no direct mutagenesis of NSUN5 catalytic residues","pmids":["38014838"],"is_preprint":false},{"year":2024,"finding":"NSUN5 knockdown in mouse preimplantation embryos impairs blastocyst formation, reduces cell numbers, increases apoptosis, abolishes nuclear translocation of YAP1 at the morula stage, alters the CDX2/OCT4 cell ratio, and upregulates Hippo pathway kinases LATS1 and LATS2, placing NSUN5 upstream of Hippo pathway regulation during early embryogenesis.","method":"siRNA knockdown in mouse embryos, immunofluorescence for YAP1 nuclear translocation, CDX2/OCT4 staining, qPCR for Lats1/Lats2","journal":"Reproduction (Cambridge, England)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean loss-of-function with defined cellular and molecular phenotypes (YAP1 localization, lineage marker ratios, pathway gene expression) in a single lab study; pathway placement established by epistasis-like readout","pmids":["38670153"],"is_preprint":false},{"year":2008,"finding":"NOL1 (NSUN5) contains a U12-dependent intron (intron F) with a fully consensus branch site sequence (UUCCUUAAC). Mutations at individual positions of this branch site reduced correct U12-dependent splicing, activated cryptic splice sites, and the fidelity of splicing correlated with predicted thermodynamic stability of the branch site:U12 snRNA interaction.","method":"Minigene mutagenesis, in vivo splicing analysis, RT-PCR","journal":"RNA (New York, N.Y.)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — systematic mutagenesis of branch site positions with in vivo splicing readout; establishes the splicing mechanism for the NOL1/NSUN5 pre-mRNA intron, though it characterizes the intron rather than the NSUN5 protein itself","pmids":["18824513"],"is_preprint":false}],"current_model":"NSUN5 (p120/NOL1) is an RNA:m5C-methyltransferase that methylates position 2870 in domain V of 28S/25S rRNA and also binds and methylates specific mRNAs (e.g., SLC7A11) to promote their translation; its expression is transcriptionally activated downstream of G-CSF/STAT3/STAT5 signaling, and loss of NSUN5 in preimplantation embryos dysregulates the Hippo pathway (upregulating LATS1/2, blocking YAP1 nuclear translocation) to impair cell proliferation and lineage differentiation."},"narrative":{"mechanistic_narrative":"NSUN5 (p120/NOL1/WBSCR20) is an RNA:m5C-methyltransferase that controls translation by depositing 5-methylcytosine on ribosomal and messenger RNA [PMID:26196125, PMID:38014838]. It methylates position 2870 in domain V of 25S/28S rRNA and functionally substitutes for the yeast Nop2p orthologue, with its N-terminal domain required for correct localization and cellular function [PMID:26196125]. Beyond rRNA, NSUN5 binds SLC7A11 mRNA and promotes its m5C methylation to enhance SLC7A11 protein translation, conferring resistance to ferroptosis in liver cells [PMID:38014838]. NSUN5 expression is directly activated downstream of G-CSF signaling through STAT3 and STAT5 binding within the first intron, and its inappropriate overexpression disrupts normal neutrophil maturation [PMID:16641140]. During early development, loss of NSUN5 in mouse preimplantation embryos impairs blastocyst formation, increases apoptosis, and dysregulates the Hippo pathway by upregulating LATS1/LATS2 and abolishing nuclear translocation of YAP1, altering CDX2/OCT4 lineage marker ratios [PMID:38670153]. The gene maps to the Williams-Beuren syndrome deletion region at 7q11.23 [PMID:11978965].","teleology":[{"year":2001,"claim":"Established the molecular identity of NSUN5/WBSCR20 as a p120/NOL1-like nucleolar protein and placed it within a disease-relevant genomic locus, framing it as a candidate proliferation-associated factor.","evidence":"Sequence homology analysis, genomic mapping, and tissue expression analysis","pmids":["11978965"],"confidence":"Low","gaps":["Characterization based on sequence similarity only with no biochemical or functional experiments on the protein","Enzymatic activity not tested","Contribution to Williams-Beuren syndrome phenotype not established"]},{"year":2006,"claim":"Answered how NSUN5 is transcriptionally controlled and connected its expression to a defined cytokine signaling pathway and a cell-fate consequence.","evidence":"Oligonucleotide pull-down, transient transfection, and loss-of-function in STAT3-deficient mouse bone marrow with morphological/marker readout","pmids":["16641140"],"confidence":"Medium","gaps":["Did not establish whether the methyltransferase activity is required for the neutrophil maturation phenotype","Direct RNA substrates in this context not identified"]},{"year":2008,"claim":"Defined the U12-dependent splicing mechanism of the NOL1/NSUN5 pre-mRNA intron, addressing how the transcript is processed but not the protein's function.","evidence":"Minigene mutagenesis of branch site positions with in vivo splicing RT-PCR readout","pmids":["18824513"],"confidence":"Medium","gaps":["Characterizes the intron, not the NSUN5 protein","Functional impact of mis-splicing on NSUN5 protein levels not measured"]},{"year":2015,"claim":"Defined the core enzymatic activity, identifying NSUN5 as an RNA:m5C-methyltransferase acting on a specific rRNA site and establishing functional conservation with the yeast Nop2p.","evidence":"RNA bisulfite sequencing, HPLC-MS/MS, functional complementation of nop2Δ yeast, and chimeric domain-swap analysis","pmids":["26196125"],"confidence":"High","gaps":["Downstream consequences of 28S rRNA methylation on ribosome function not resolved","Catalytic residues not mapped in this study"]},{"year":2023,"claim":"Extended NSUN5 function beyond rRNA by showing it methylates a specific mRNA to control translation, linking its activity to ferroptosis resistance.","evidence":"Dot blot for global m5C, immunofluorescence co-localization, and RNA binding protein immunoprecipitation","pmids":["38014838"],"confidence":"Medium","gaps":["No mutagenesis of NSUN5 catalytic residues to confirm methylation-dependence of the SLC7A11 effect","Methylated cytosine position on SLC7A11 mRNA not mapped"]},{"year":2024,"claim":"Placed NSUN5 upstream of Hippo pathway regulation in early development, connecting its loss to defective YAP1 signaling and lineage specification.","evidence":"siRNA knockdown in mouse embryos with YAP1/CDX2/OCT4 immunofluorescence and Lats1/Lats2 qPCR","pmids":["38670153"],"confidence":"Medium","gaps":["Mechanism linking NSUN5 methyltransferase activity to LATS1/2 upregulation not defined","Direct RNA targets mediating the Hippo effect not identified"]},{"year":null,"claim":"How NSUN5's catalytic m5C activity mechanistically connects its diverse phenotypes — ribosome function, mRNA-selective translation, neutrophil maturation, and Hippo/developmental control — remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No structural model of the human enzyme-RNA complex","Catalytic-dead mutants not used to test methylation-dependence across phenotypes","Full mRNA target repertoire undefined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140098","term_label":"catalytic activity, acting on RNA","supporting_discovery_ids":[0,3]},{"term_id":"GO:0003723","term_label":"RNA binding","supporting_discovery_ids":[0,3]},{"term_id":"GO:0016740","term_label":"transferase activity","supporting_discovery_ids":[0]}],"localization":[{"term_id":"GO:0005730","term_label":"nucleolus","supporting_discovery_ids":[0]}],"pathway":[{"term_id":"R-HSA-8953854","term_label":"Metabolism of RNA","supporting_discovery_ids":[0,3]}],"complexes":[],"partners":["STAT3","STAT5","SLC7A11"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q96P11","full_name":"28S rRNA (cytosine-C(5))-methyltransferase","aliases":["NOL1-related protein","NOL1R","NOL1/NOP2/Sun domain family member 5","Williams-Beuren syndrome chromosomal region 20A protein"],"length_aa":429,"mass_kda":46.7,"function":"S-adenosyl-L-methionine-dependent methyltransferase that specifically methylates the C(5) position of cytosine 3782 (m5C3782) in 28S rRNA (PubMed:23913415, PubMed:31428936, PubMed:31722427). m5C3782 promotes protein translation without affecting ribosome biogenesis and fidelity (PubMed:31428936, PubMed:31722427). Required for corpus callosum and cerebral cortex development (By similarity)","subcellular_location":"Nucleus, nucleolus","url":"https://www.uniprot.org/uniprotkb/Q96P11/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/NSUN5","classification":"Not Classified","n_dependent_lines":45,"n_total_lines":1208,"dependency_fraction":0.037251655629139076},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"FKBP5","stoichiometry":0.2},{"gene":"NCAPH","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/NSUN5","total_profiled":1310},"omim":[{"mim_id":"618630","title":"tRNA METHYLTRANSFERASE SUBUNIT 11-2; TRMT112","url":"https://www.omim.org/entry/618630"},{"mim_id":"615732","title":"NOP2/SUN RNA METHYLTRANSFERASE FAMILY, MEMBER 5; NSUN5","url":"https://www.omim.org/entry/615732"},{"mim_id":"194050","title":"WILLIAMS-BEUREN SYNDROME; WBS","url":"https://www.omim.org/entry/194050"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Enhanced","locations":[{"location":"Nucleoplasm","reliability":"Enhanced"},{"location":"Nucleoli","reliability":"Enhanced"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/NSUN5"},"hgnc":{"alias_symbol":["NOL1R","p120(NOL1)","FLJ10267","NSUN5A","Ynl022cL"],"prev_symbol":["WBSCR20","WBSCR20A"]},"alphafold":{"accession":"Q96P11","domains":[{"cath_id":"-","chopping":"4-122","consensus_level":"high","plddt":90.0205,"start":4,"end":122},{"cath_id":"3.30.70.1170","chopping":"136-211","consensus_level":"high","plddt":95.762,"start":136,"end":211},{"cath_id":"3.40.50.150","chopping":"218-425","consensus_level":"high","plddt":93.2478,"start":218,"end":425}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96P11","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q96P11-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q96P11-F1-predicted_aligned_error_v6.png","plddt_mean":91.44},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=NSUN5","jax_strain_url":"https://www.jax.org/strain/search?query=NSUN5"},"sequence":{"accession":"Q96P11","fasta_url":"https://rest.uniprot.org/uniprotkb/Q96P11.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q96P11/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q96P11"}},"corpus_meta":[{"pmid":"26196125","id":"PMC_26196125","title":"Eukaryotic rRNA Modification by Yeast 5-Methylcytosine-Methyltransferases and Human Proliferation-Associated Antigen p120.","date":"2015","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/26196125","citation_count":90,"is_preprint":false},{"pmid":"23816522","id":"PMC_23816522","title":"Expression of NOL1/NOP2/sun domain (Nsun) RNA methyltransferase family genes in early mouse embryogenesis.","date":"2013","source":"Gene expression patterns : GEP","url":"https://pubmed.ncbi.nlm.nih.gov/23816522","citation_count":80,"is_preprint":false},{"pmid":"11978965","id":"PMC_11978965","title":"Characterization of two novel genes, WBSCR20 and WBSCR22, deleted in Williams-Beuren syndrome.","date":"2001","source":"Cytogenetics and cell genetics","url":"https://pubmed.ncbi.nlm.nih.gov/11978965","citation_count":76,"is_preprint":false},{"pmid":"9767141","id":"PMC_9767141","title":"NCL1, a novel gene for a non-essential nuclear protein in Saccharomyces cerevisiae.","date":"1998","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/9767141","citation_count":49,"is_preprint":false},{"pmid":"18185522","id":"PMC_18185522","title":"E2A-ZNF384 and NOL1-E2A fusion created by a cryptic t(12;19)(p13.3; p13.3) in acute leukemia.","date":"2008","source":"Leukemia","url":"https://pubmed.ncbi.nlm.nih.gov/18185522","citation_count":33,"is_preprint":false},{"pmid":"38014838","id":"PMC_38014838","title":"Niujiao Dihuang Jiedu decoction promotes SLC7A11 m5C methylation modification against ferroptosis in acute-on-chronic liver failure.","date":"2023","source":"Phytomedicine : international journal of phytotherapy and phytopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/38014838","citation_count":12,"is_preprint":false},{"pmid":"18824513","id":"PMC_18824513","title":"Mutational analysis of the U12-dependent branch site consensus sequence.","date":"2008","source":"RNA (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/18824513","citation_count":7,"is_preprint":false},{"pmid":"38670153","id":"PMC_38670153","title":"NSUN5 is essential for proper cell proliferation and differentiation of mouse preimplantation embryos.","date":"2024","source":"Reproduction (Cambridge, England)","url":"https://pubmed.ncbi.nlm.nih.gov/38670153","citation_count":5,"is_preprint":false},{"pmid":"36698387","id":"PMC_36698387","title":"Genetic variants in m5C modification core genes are associated with the risk of Chinese pediatric acute lymphoblastic leukemia: A five-center case-control study.","date":"2023","source":"Frontiers in oncology","url":"https://pubmed.ncbi.nlm.nih.gov/36698387","citation_count":4,"is_preprint":false},{"pmid":"16641140","id":"PMC_16641140","title":"p120 nucleolar-proliferating antigen is a direct target of G-CSF signaling during myeloid differentiation.","date":"2006","source":"Journal of leukocyte biology","url":"https://pubmed.ncbi.nlm.nih.gov/16641140","citation_count":3,"is_preprint":false},{"pmid":"41462962","id":"PMC_41462962","title":"The Role of NSUN Family Genes in m5C Methylation and Diseases.","date":"2025","source":"Biomedicines","url":"https://pubmed.ncbi.nlm.nih.gov/41462962","citation_count":1,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":7940,"output_tokens":1720,"usd":0.02481,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8524,"output_tokens":2319,"usd":0.050298,"stage2_stop_reason":"end_turn"},"total_usd":0.075108,"stage1_batch_id":"msgbatch_013a8chtv3AWyTqv4z4sEF4C","stage2_batch_id":"msgbatch_01AHsuW63vinsvuTgzmQ3n62","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2015,\n      \"finding\": \"Human p120 (NOL1/NSUN5) possesses RNA:m5C-methyltransferase activity and methylates position 2870 in domain V of 25S rRNA, functionally complementing the yeast Nop2p orthologue in a nop2Δ strain. Chimeric protein analysis revealed the importance of the Nop2 N-terminal domain for correct protein localization and cellular function.\",\n      \"method\": \"RNA bisulfite sequencing, HPLC-MS/MS, functional complementation of nop2Δ yeast, chimeric protein analysis\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — direct in vitro enzymatic activity assay (bisulfite sequencing + HPLC-MS/MS) combined with functional genetic complementation and domain-swap mutagenesis; multiple orthogonal methods in one study\",\n      \"pmids\": [\"26196125\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"NSUN5 (WBSCR20) encodes a novel protein with similarity to p120 (NOL1), a proliferation-associated nucleolar antigen; the gene maps to the Williams-Beuren syndrome deletion region at 7q11.23. A highly similar putative gene, WBSCR20B, flanks the WBS deletion at the telomeric side.\",\n      \"method\": \"Sequence homology analysis, genomic mapping, expression analysis in tissues\",\n      \"journal\": \"Cytogenetics and cell genetics\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 4 / Weak — characterization based on sequence similarity and genomic mapping only; no direct biochemical or functional experiments performed on NSUN5 protein\",\n      \"pmids\": [\"11978965\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"p120 (NOL1/NSUN5) expression is directly regulated by G-CSF signaling through STAT3 and STAT5 binding to a site in the first intron of the gene. Overexpression of p120 in G-CSF-induced 32D cells caused loss of lactoferrin expression, a marker of normal neutrophil maturation, indicating that inappropriate p120 expression results in aberrant neutrophil maturation.\",\n      \"method\": \"cDNA representational difference analysis, Northern blot, transient transfection, oligonucleotide pull-down assay, loss-of-function in STAT3-deficient mouse bone marrow, overexpression with morphological and marker readout\",\n      \"journal\": \"Journal of leukocyte biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal methods (pull-down, transfection, in vivo knockout model) in a single lab study demonstrating pathway placement and functional consequence\",\n      \"pmids\": [\"16641140\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"NSUN5 associates with SLC7A11 mRNA and promotes its m5C methylation, enhancing SLC7A11 protein translation and conferring resistance against ferroptosis in liver cells.\",\n      \"method\": \"Dot blot (global m5C levels), immunofluorescence co-localization, RNA binding protein immunoprecipitation (RIP)\",\n      \"journal\": \"Phytomedicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — RIP demonstrates direct binding of NSUN5 to SLC7A11 mRNA; functional ferroptosis resistance readout; single lab with two orthogonal binding/localization methods but no direct mutagenesis of NSUN5 catalytic residues\",\n      \"pmids\": [\"38014838\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"NSUN5 knockdown in mouse preimplantation embryos impairs blastocyst formation, reduces cell numbers, increases apoptosis, abolishes nuclear translocation of YAP1 at the morula stage, alters the CDX2/OCT4 cell ratio, and upregulates Hippo pathway kinases LATS1 and LATS2, placing NSUN5 upstream of Hippo pathway regulation during early embryogenesis.\",\n      \"method\": \"siRNA knockdown in mouse embryos, immunofluorescence for YAP1 nuclear translocation, CDX2/OCT4 staining, qPCR for Lats1/Lats2\",\n      \"journal\": \"Reproduction (Cambridge, England)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean loss-of-function with defined cellular and molecular phenotypes (YAP1 localization, lineage marker ratios, pathway gene expression) in a single lab study; pathway placement established by epistasis-like readout\",\n      \"pmids\": [\"38670153\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"NOL1 (NSUN5) contains a U12-dependent intron (intron F) with a fully consensus branch site sequence (UUCCUUAAC). Mutations at individual positions of this branch site reduced correct U12-dependent splicing, activated cryptic splice sites, and the fidelity of splicing correlated with predicted thermodynamic stability of the branch site:U12 snRNA interaction.\",\n      \"method\": \"Minigene mutagenesis, in vivo splicing analysis, RT-PCR\",\n      \"journal\": \"RNA (New York, N.Y.)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — systematic mutagenesis of branch site positions with in vivo splicing readout; establishes the splicing mechanism for the NOL1/NSUN5 pre-mRNA intron, though it characterizes the intron rather than the NSUN5 protein itself\",\n      \"pmids\": [\"18824513\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"NSUN5 (p120/NOL1) is an RNA:m5C-methyltransferase that methylates position 2870 in domain V of 28S/25S rRNA and also binds and methylates specific mRNAs (e.g., SLC7A11) to promote their translation; its expression is transcriptionally activated downstream of G-CSF/STAT3/STAT5 signaling, and loss of NSUN5 in preimplantation embryos dysregulates the Hippo pathway (upregulating LATS1/2, blocking YAP1 nuclear translocation) to impair cell proliferation and lineage differentiation.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"NSUN5 (p120/NOL1/WBSCR20) is an RNA:m5C-methyltransferase that controls translation by depositing 5-methylcytosine on ribosomal and messenger RNA [#0, #3]. It methylates position 2870 in domain V of 25S/28S rRNA and functionally substitutes for the yeast Nop2p orthologue, with its N-terminal domain required for correct localization and cellular function [#0]. Beyond rRNA, NSUN5 binds SLC7A11 mRNA and promotes its m5C methylation to enhance SLC7A11 protein translation, conferring resistance to ferroptosis in liver cells [#3]. NSUN5 expression is directly activated downstream of G-CSF signaling through STAT3 and STAT5 binding within the first intron, and its inappropriate overexpression disrupts normal neutrophil maturation [#2]. During early development, loss of NSUN5 in mouse preimplantation embryos impairs blastocyst formation, increases apoptosis, and dysregulates the Hippo pathway by upregulating LATS1/LATS2 and abolishing nuclear translocation of YAP1, altering CDX2/OCT4 lineage marker ratios [#4]. The gene maps to the Williams-Beuren syndrome deletion region at 7q11.23 [#1].\",\n  \"teleology\": [\n    {\n      \"year\": 2001,\n      \"claim\": \"Established the molecular identity of NSUN5/WBSCR20 as a p120/NOL1-like nucleolar protein and placed it within a disease-relevant genomic locus, framing it as a candidate proliferation-associated factor.\",\n      \"evidence\": \"Sequence homology analysis, genomic mapping, and tissue expression analysis\",\n      \"pmids\": [\"11978965\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Characterization based on sequence similarity only with no biochemical or functional experiments on the protein\", \"Enzymatic activity not tested\", \"Contribution to Williams-Beuren syndrome phenotype not established\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Answered how NSUN5 is transcriptionally controlled and connected its expression to a defined cytokine signaling pathway and a cell-fate consequence.\",\n      \"evidence\": \"Oligonucleotide pull-down, transient transfection, and loss-of-function in STAT3-deficient mouse bone marrow with morphological/marker readout\",\n      \"pmids\": [\"16641140\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Did not establish whether the methyltransferase activity is required for the neutrophil maturation phenotype\", \"Direct RNA substrates in this context not identified\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Defined the U12-dependent splicing mechanism of the NOL1/NSUN5 pre-mRNA intron, addressing how the transcript is processed but not the protein's function.\",\n      \"evidence\": \"Minigene mutagenesis of branch site positions with in vivo splicing RT-PCR readout\",\n      \"pmids\": [\"18824513\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Characterizes the intron, not the NSUN5 protein\", \"Functional impact of mis-splicing on NSUN5 protein levels not measured\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Defined the core enzymatic activity, identifying NSUN5 as an RNA:m5C-methyltransferase acting on a specific rRNA site and establishing functional conservation with the yeast Nop2p.\",\n      \"evidence\": \"RNA bisulfite sequencing, HPLC-MS/MS, functional complementation of nop2\\u0394 yeast, and chimeric domain-swap analysis\",\n      \"pmids\": [\"26196125\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Downstream consequences of 28S rRNA methylation on ribosome function not resolved\", \"Catalytic residues not mapped in this study\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Extended NSUN5 function beyond rRNA by showing it methylates a specific mRNA to control translation, linking its activity to ferroptosis resistance.\",\n      \"evidence\": \"Dot blot for global m5C, immunofluorescence co-localization, and RNA binding protein immunoprecipitation\",\n      \"pmids\": [\"38014838\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No mutagenesis of NSUN5 catalytic residues to confirm methylation-dependence of the SLC7A11 effect\", \"Methylated cytosine position on SLC7A11 mRNA not mapped\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Placed NSUN5 upstream of Hippo pathway regulation in early development, connecting its loss to defective YAP1 signaling and lineage specification.\",\n      \"evidence\": \"siRNA knockdown in mouse embryos with YAP1/CDX2/OCT4 immunofluorescence and Lats1/Lats2 qPCR\",\n      \"pmids\": [\"38670153\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism linking NSUN5 methyltransferase activity to LATS1/2 upregulation not defined\", \"Direct RNA targets mediating the Hippo effect not identified\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How NSUN5's catalytic m5C activity mechanistically connects its diverse phenotypes — ribosome function, mRNA-selective translation, neutrophil maturation, and Hippo/developmental control — remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural model of the human enzyme-RNA complex\", \"Catalytic-dead mutants not used to test methylation-dependence across phenotypes\", \"Full mRNA target repertoire undefined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140098\", \"supporting_discovery_ids\": [0, 3]},\n      {\"term_id\": \"GO:0003723\", \"supporting_discovery_ids\": [0, 3]},\n      {\"term_id\": \"GO:0016740\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005730\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-8953854\", \"supporting_discovery_ids\": [0, 3]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"STAT3\", \"STAT5\", \"SLC7A11\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}