{"gene":"TAF9B","run_date":"2026-06-10T10:51:54","timeline":{"discoveries":[{"year":2005,"finding":"TAF9b (TAF9L) is a bona fide subunit of both TFIID and TFTC transcriptional regulatory complexes, where it forms histone fold pair interactions with TAF6 analogous to TAF9-TAF6 interactions.","method":"MALDI mass spectrometry identification, Co-immunoprecipitation, in vitro and in vivo interaction assays","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP, in vitro and in vivo interaction assays, mass spectrometry identification, multiple orthogonal methods in a single rigorous study","pmids":["15899866"],"is_preprint":false},{"year":2005,"finding":"TAF9b and TAF9 are differentially induced during apoptosis and differ in their ability to stabilize p53, with TAF9b acting as a coactivator/stabilizer of p53.","method":"siRNA knockdown, gene expression analysis, apoptosis assays","journal":"Molecular and cellular biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA knockdown with defined phenotypic readout, single lab with two orthogonal methods (expression analysis + apoptosis assay)","pmids":["15899866"],"is_preprint":false},{"year":2005,"finding":"siRNA knockdown of TAF9b is essential for cell viability, and TAF9b regulates a distinct set of genes from TAF9 with only small overlap.","method":"siRNA knockdown, gene expression microarray analysis","journal":"Molecular and cellular biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA knockdown with defined cellular phenotype and gene expression profiling, single lab, two orthogonal methods","pmids":["15899866"],"is_preprint":false},{"year":2003,"finding":"TAF9L (TAF9b) is partly redundant with TAF9, but RNA interference experiments indicate TAF9L is essential for HeLa cell growth and plays a role in transcriptional repression and/or silencing.","method":"Conditional TAF9 allele in DT40 cells, RNA interference, transcription assays","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — RNAi with defined cellular phenotype, genetic epistasis via conditional allele, single lab with multiple orthogonal approaches","pmids":["12837753"],"is_preprint":false},{"year":2019,"finding":"miR-146a targets TAF9b (a coactivator and stabilizer of p53), indirectly destabilizing p53 and thereby inhibiting apoptosis and modulating autophagy in cardiomyocytes exposed to doxorubicin.","method":"miR-146a overexpression/knockdown in cardiomyocytes, miR-146a knockout mice, target validation (presumably luciferase reporter), apoptosis/autophagy assays","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo knockout validation combined with cellular overexpression/knockdown experiments and functional readouts, single lab","pmids":["31511497"],"is_preprint":false},{"year":2021,"finding":"TAF9B activates the AKT/mTOR signaling pathway and regulates apoptosis by upregulating Bcl-2 and downregulating Bax and Cleaved-caspase-3 in osteosarcoma cells; miR-7-5p binds the 3'UTR of TAF9B to suppress its translation.","method":"TAF9B overexpression and knockdown, dual luciferase reporter assay, western blotting, flow cytometry","journal":"OncoTargets and therapy","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — dual luciferase reporter for miRNA-target interaction, western blot for pathway activation, overexpression/knockdown phenotyping; single lab, multiple methods","pmids":["33958878"],"is_preprint":false},{"year":2022,"finding":"miR-199 targets TAF9b (confirmed by dual-luciferase reporter assay), and TAF9b knockdown reverses the myocardial protective effect of miR-199 inhibition, placing TAF9b downstream of miR-199 in doxorubicin-induced cardiomyocyte apoptosis and autophagy.","method":"Dual-luciferase reporter assay, TAF9b knockdown, TUNEL staining, flow cytometry, western blotting","journal":"Evidence-based complementary and alternative medicine","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — dual luciferase reporter, epistasis via knockdown rescue experiment, single lab, multiple orthogonal methods","pmids":["35873641"],"is_preprint":false},{"year":2026,"finding":"TAF9B is required for magnetoelectric nanoparticle-driven TH2 cell expansion and IL-4-dependent type II immune response; Taf9b-deficient T cells fail to respond to magnetoelectric stimulation, demonstrating TAF9B is essential for this transcriptional programming in TH2 cells.","method":"Taf9b-deficient mouse T cells, adoptive transfer experiments, murine colitis and arthritis models, genetic loss-of-function","journal":"Science advances","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic loss-of-function (Taf9b-deficient cells) with defined cellular phenotype in vivo, single lab","pmids":["41671377"],"is_preprint":false}],"current_model":"TAF9B (TAF9L/TAFII31L) is a paralog of TAF9 that functions as a bona fide subunit of the TFIID and TFTC transcriptional regulatory complexes, forming histone fold pair interactions with TAF6; it is essential for cell viability, regulates a largely distinct set of genes from TAF9, differentially stabilizes p53 during apoptosis, activates AKT/mTOR and Bcl-2/Bax apoptotic pathways, and is required for TH2 cell transcriptional programming—with its expression regulated post-transcriptionally by miR-146a, miR-7-5p, and miR-199 via 3'UTR targeting."},"narrative":{"mechanistic_narrative":"TAF9B (TAF9L/TAFII31L) is a paralog of TAF9 that functions as a bona fide subunit of the general transcription complexes TFIID and TFTC, where it integrates via histone-fold pairing with TAF6 analogous to TAF9 [PMID:15899866]. Despite this structural redundancy, TAF9B is essential for cell viability and directs a transcriptional program largely distinct from TAF9, with only minimal overlap in regulated genes [PMID:15899866, PMID:12837753]. TAF9B acts as a coactivator and stabilizer of p53, and TAF9B and TAF9 are differentially induced during apoptosis [PMID:15899866]. Beyond core transcription, TAF9B supports specialized transcriptional programming, being required for IL-4-dependent TH2 cell expansion and type II immune responses [PMID:41671377]. Multiple microRNAs converge on the TAF9B 3'UTR—miR-146a, miR-7-5p, and miR-199—to post-transcriptionally restrict its expression and thereby modulate p53-dependent apoptosis and autophagy in disease contexts including doxorubicin-treated cardiomyocytes and osteosarcoma cells [PMID:31511497, PMID:33958878, PMID:35873641].","teleology":[{"year":2003,"claim":"Established whether the TAF9 paralog TAF9L carries an independent, non-redundant function rather than being a mere backup copy, by testing its requirement for cell growth.","evidence":"RNA interference and a conditional TAF9 allele in DT40/HeLa cells with transcription assays","pmids":["12837753"],"confidence":"Medium","gaps":["Did not define the molecular complex context of TAF9L action","Mechanism of the implied transcriptional repression/silencing role unresolved","Direct target genes not identified"]},{"year":2005,"claim":"Resolved how TAF9B is incorporated into the transcriptional machinery and showed it occupies a genuine subunit role, establishing it as a TFIID/TFTC component that pairs with TAF6 via histone folds.","evidence":"MALDI mass spectrometry, reciprocal Co-IP, and in vitro/in vivo interaction assays","pmids":["15899866"],"confidence":"High","gaps":["Stoichiometry of TAF9 versus TAF9B within individual complexes not defined","No structural model of the TAF9B-containing complex"]},{"year":2005,"claim":"Distinguished TAF9B from TAF9 functionally, showing it regulates a distinct gene set, is essential for viability, and uniquely stabilizes p53 during apoptosis.","evidence":"siRNA knockdown, gene expression microarray, and apoptosis assays","pmids":["15899866"],"confidence":"Medium","gaps":["Molecular basis for differential gene selectivity versus TAF9 unknown","Mechanism of p53 stabilization not defined","Single-lab evidence for the apoptosis link"]},{"year":2021,"claim":"Connected TAF9B to downstream survival signaling, implicating it in AKT/mTOR activation and Bcl-2/Bax-mediated apoptotic control.","evidence":"TAF9B overexpression/knockdown, dual-luciferase reporter, western blotting, and flow cytometry in osteosarcoma cells","pmids":["33958878"],"confidence":"Medium","gaps":["Whether AKT/mTOR effects are direct transcriptional outputs of TAF9B unknown","Single cancer cell-type context"]},{"year":2019,"claim":"Defined post-transcriptional control of TAF9B, showing microRNAs targeting its 3'UTR govern p53-dependent apoptosis and autophagy.","evidence":"miR-146a, miR-7-5p, and miR-199 overexpression/knockdown, dual-luciferase reporters, and knockout/functional readouts in cardiomyocytes and tumor cells","pmids":["31511497","33958878","35873641"],"confidence":"Medium","gaps":["Endogenous regulatory hierarchy among the three microRNAs unresolved","Physiological conditions selecting each microRNA-TAF9B axis not defined"]},{"year":2026,"claim":"Extended TAF9B function to specialized immune transcriptional programming, showing it is required for TH2 cell expansion and IL-4-dependent type II responses.","evidence":"Taf9b-deficient mouse T cells, adoptive transfer, and murine colitis/arthritis models","pmids":["41671377"],"confidence":"Medium","gaps":["TAF9B target genes within the TH2 program not identified","Whether the role requires TFIID/TFTC incorporation not tested"]},{"year":null,"claim":"How TAF9B-containing complexes achieve gene selectivity distinct from TAF9, and how this links to its p53, AKT/mTOR, and TH2 roles, remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No mechanistic link between TAF9B complex composition and its distinct target genes","No structural data on TAF9B-containing TFIID/TFTC","Direct transcriptional targets in p53 and immune programs unidentified"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[0,1,2]},{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[0]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[0]}],"pathway":[{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[0,2]}],"complexes":["TFIID","TFTC"],"partners":["TAF6"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9HBM6","full_name":"Transcription initiation factor TFIID subunit 9B","aliases":["Neuronal cell death-related protein 7","DN-7","Transcription initiation factor TFIID subunit 9-like","Transcription-associated factor TAFII31L"],"length_aa":251,"mass_kda":27.6,"function":"Essential for cell viability. TAF9 and TAF9B are involved in transcriptional activation as well as repression of distinct but overlapping sets of genes. May have a role in gene regulation associated with apoptosis. TAFs are components of the transcription factor IID (TFIID) complex, the TBP-free TAFII complex (TFTC), the PCAF histone acetylase complex and the STAGA transcription coactivator-HAT complex. TFIID or TFTC are essential for the regulation of RNA polymerase II-mediated transcription","subcellular_location":"Nucleus","url":"https://www.uniprot.org/uniprotkb/Q9HBM6/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/TAF9B","classification":"Not Classified","n_dependent_lines":5,"n_total_lines":1208,"dependency_fraction":0.0041390728476821195},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"TAF1","stoichiometry":10.0},{"gene":"TAF12","stoichiometry":10.0},{"gene":"TRRAP","stoichiometry":10.0},{"gene":"MED19","stoichiometry":4.0},{"gene":"USP22","stoichiometry":4.0},{"gene":"ENY2","stoichiometry":0.2},{"gene":"MED9","stoichiometry":0.2},{"gene":"SF3B3","stoichiometry":0.2},{"gene":"SF3B5","stoichiometry":0.2},{"gene":"TBP","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/TAF9B","total_profiled":1310},"omim":[{"mim_id":"612116","title":"UBIQUITIN-SPECIFIC PROTEASE 22; USP22","url":"https://www.omim.org/entry/612116"},{"mim_id":"600822","title":"TATA BOX-BINDING PROTEIN-ASSOCIATED FACTOR 9; TAF9","url":"https://www.omim.org/entry/600822"},{"mim_id":"300754","title":"TAF9B RNA POLYMERASE II, TATA BOX-BINDING PROTEIN-ASSOCIATED FACTOR, 31-KD; TAF9B","url":"https://www.omim.org/entry/300754"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Nucleoplasm","reliability":"Approved"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/TAF9B"},"hgnc":{"alias_symbol":["TAFII31L","DN-7","DN7","TFIID-31"],"prev_symbol":["TAF9L"]},"alphafold":{"accession":"Q9HBM6","domains":[],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9HBM6","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9HBM6-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9HBM6-F1-predicted_aligned_error_v6.png","plddt_mean":66.56},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=TAF9B","jax_strain_url":"https://www.jax.org/strain/search?query=TAF9B"},"sequence":{"accession":"Q9HBM6","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9HBM6.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9HBM6/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9HBM6"}},"corpus_meta":[{"pmid":"31511497","id":"PMC_31511497","title":"miR-146a attenuates apoptosis and modulates autophagy by targeting TAF9b/P53 pathway in doxorubicin-induced cardiotoxicity.","date":"2019","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/31511497","citation_count":105,"is_preprint":false},{"pmid":"15899866","id":"PMC_15899866","title":"TAF9b (formerly TAF9L) is a bona fide TAF that has unique and overlapping roles with TAF9.","date":"2005","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/15899866","citation_count":54,"is_preprint":false},{"pmid":"12879254","id":"PMC_12879254","title":"Genetic mapping of Dn7, a rye gene conferring resistance to the Russian wheat aphid in wheat.","date":"2003","source":"TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik","url":"https://pubmed.ncbi.nlm.nih.gov/12879254","citation_count":20,"is_preprint":false},{"pmid":"12837753","id":"PMC_12837753","title":"In vivo functional analysis of the histone 3-like TAF9 and a TAF9-related factor, TAF9L.","date":"2003","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/12837753","citation_count":15,"is_preprint":false},{"pmid":"16334342","id":"PMC_16334342","title":"Comparison of Dn4- and Dn7-carrying spring wheat genotypes artificially infested with Russian wheat aphid (Homoptera: Aphididae) biotype 1.","date":"2005","source":"Journal of economic entomology","url":"https://pubmed.ncbi.nlm.nih.gov/16334342","citation_count":10,"is_preprint":false},{"pmid":"33958878","id":"PMC_33958878","title":"Downregulation of TAF9B by miR-7-5p Inhibits the Progression of Osteosarcoma.","date":"2021","source":"OncoTargets and therapy","url":"https://pubmed.ncbi.nlm.nih.gov/33958878","citation_count":9,"is_preprint":false},{"pmid":"35873641","id":"PMC_35873641","title":"MiR-199 Aggravates Doxorubicin-Induced Cardiotoxicity by Targeting TAF9b.","date":"2022","source":"Evidence-based complementary and alternative medicine : eCAM","url":"https://pubmed.ncbi.nlm.nih.gov/35873641","citation_count":6,"is_preprint":false},{"pmid":"23173477","id":"PMC_23173477","title":"[Isolation and identification of aerobic denitrifying bacterium Defluvibacter lusatiensis strain DN7 and its heterotrophic nitrification ability].","date":"2012","source":"Ying yong sheng tai xue bao = The journal of applied ecology","url":"https://pubmed.ncbi.nlm.nih.gov/23173477","citation_count":1,"is_preprint":false},{"pmid":"41671377","id":"PMC_41671377","title":"Magnetoelectric nanoparticles drive TAF9B+ TH2 cell expansion to alleviate inflammation.","date":"2026","source":"Science advances","url":"https://pubmed.ncbi.nlm.nih.gov/41671377","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":6387,"output_tokens":1830,"usd":0.023305,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8691,"output_tokens":2339,"usd":0.050965,"stage2_stop_reason":"end_turn"},"total_usd":0.07427,"stage1_batch_id":"msgbatch_017qqVz33Ga63SCDwzb35XPb","stage2_batch_id":"msgbatch_01Scr2Ei9x4HJMiRGxwrmvLK","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2005,\n      \"finding\": \"TAF9b (TAF9L) is a bona fide subunit of both TFIID and TFTC transcriptional regulatory complexes, where it forms histone fold pair interactions with TAF6 analogous to TAF9-TAF6 interactions.\",\n      \"method\": \"MALDI mass spectrometry identification, Co-immunoprecipitation, in vitro and in vivo interaction assays\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP, in vitro and in vivo interaction assays, mass spectrometry identification, multiple orthogonal methods in a single rigorous study\",\n      \"pmids\": [\"15899866\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"TAF9b and TAF9 are differentially induced during apoptosis and differ in their ability to stabilize p53, with TAF9b acting as a coactivator/stabilizer of p53.\",\n      \"method\": \"siRNA knockdown, gene expression analysis, apoptosis assays\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA knockdown with defined phenotypic readout, single lab with two orthogonal methods (expression analysis + apoptosis assay)\",\n      \"pmids\": [\"15899866\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"siRNA knockdown of TAF9b is essential for cell viability, and TAF9b regulates a distinct set of genes from TAF9 with only small overlap.\",\n      \"method\": \"siRNA knockdown, gene expression microarray analysis\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA knockdown with defined cellular phenotype and gene expression profiling, single lab, two orthogonal methods\",\n      \"pmids\": [\"15899866\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"TAF9L (TAF9b) is partly redundant with TAF9, but RNA interference experiments indicate TAF9L is essential for HeLa cell growth and plays a role in transcriptional repression and/or silencing.\",\n      \"method\": \"Conditional TAF9 allele in DT40 cells, RNA interference, transcription assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — RNAi with defined cellular phenotype, genetic epistasis via conditional allele, single lab with multiple orthogonal approaches\",\n      \"pmids\": [\"12837753\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"miR-146a targets TAF9b (a coactivator and stabilizer of p53), indirectly destabilizing p53 and thereby inhibiting apoptosis and modulating autophagy in cardiomyocytes exposed to doxorubicin.\",\n      \"method\": \"miR-146a overexpression/knockdown in cardiomyocytes, miR-146a knockout mice, target validation (presumably luciferase reporter), apoptosis/autophagy assays\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo knockout validation combined with cellular overexpression/knockdown experiments and functional readouts, single lab\",\n      \"pmids\": [\"31511497\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"TAF9B activates the AKT/mTOR signaling pathway and regulates apoptosis by upregulating Bcl-2 and downregulating Bax and Cleaved-caspase-3 in osteosarcoma cells; miR-7-5p binds the 3'UTR of TAF9B to suppress its translation.\",\n      \"method\": \"TAF9B overexpression and knockdown, dual luciferase reporter assay, western blotting, flow cytometry\",\n      \"journal\": \"OncoTargets and therapy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — dual luciferase reporter for miRNA-target interaction, western blot for pathway activation, overexpression/knockdown phenotyping; single lab, multiple methods\",\n      \"pmids\": [\"33958878\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"miR-199 targets TAF9b (confirmed by dual-luciferase reporter assay), and TAF9b knockdown reverses the myocardial protective effect of miR-199 inhibition, placing TAF9b downstream of miR-199 in doxorubicin-induced cardiomyocyte apoptosis and autophagy.\",\n      \"method\": \"Dual-luciferase reporter assay, TAF9b knockdown, TUNEL staining, flow cytometry, western blotting\",\n      \"journal\": \"Evidence-based complementary and alternative medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — dual luciferase reporter, epistasis via knockdown rescue experiment, single lab, multiple orthogonal methods\",\n      \"pmids\": [\"35873641\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"TAF9B is required for magnetoelectric nanoparticle-driven TH2 cell expansion and IL-4-dependent type II immune response; Taf9b-deficient T cells fail to respond to magnetoelectric stimulation, demonstrating TAF9B is essential for this transcriptional programming in TH2 cells.\",\n      \"method\": \"Taf9b-deficient mouse T cells, adoptive transfer experiments, murine colitis and arthritis models, genetic loss-of-function\",\n      \"journal\": \"Science advances\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic loss-of-function (Taf9b-deficient cells) with defined cellular phenotype in vivo, single lab\",\n      \"pmids\": [\"41671377\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"TAF9B (TAF9L/TAFII31L) is a paralog of TAF9 that functions as a bona fide subunit of the TFIID and TFTC transcriptional regulatory complexes, forming histone fold pair interactions with TAF6; it is essential for cell viability, regulates a largely distinct set of genes from TAF9, differentially stabilizes p53 during apoptosis, activates AKT/mTOR and Bcl-2/Bax apoptotic pathways, and is required for TH2 cell transcriptional programming—with its expression regulated post-transcriptionally by miR-146a, miR-7-5p, and miR-199 via 3'UTR targeting.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"TAF9B (TAF9L/TAFII31L) is a paralog of TAF9 that functions as a bona fide subunit of the general transcription complexes TFIID and TFTC, where it integrates via histone-fold pairing with TAF6 analogous to TAF9 [#0]. Despite this structural redundancy, TAF9B is essential for cell viability and directs a transcriptional program largely distinct from TAF9, with only minimal overlap in regulated genes [#2, #3]. TAF9B acts as a coactivator and stabilizer of p53, and TAF9B and TAF9 are differentially induced during apoptosis [#1]. Beyond core transcription, TAF9B supports specialized transcriptional programming, being required for IL-4-dependent TH2 cell expansion and type II immune responses [#7]. Multiple microRNAs converge on the TAF9B 3'UTR—miR-146a, miR-7-5p, and miR-199—to post-transcriptionally restrict its expression and thereby modulate p53-dependent apoptosis and autophagy in disease contexts including doxorubicin-treated cardiomyocytes and osteosarcoma cells [#4, #5, #6].\",\n  \"teleology\": [\n    {\n      \"year\": 2003,\n      \"claim\": \"Established whether the TAF9 paralog TAF9L carries an independent, non-redundant function rather than being a mere backup copy, by testing its requirement for cell growth.\",\n      \"evidence\": \"RNA interference and a conditional TAF9 allele in DT40/HeLa cells with transcription assays\",\n      \"pmids\": [\"12837753\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\n        \"Did not define the molecular complex context of TAF9L action\",\n        \"Mechanism of the implied transcriptional repression/silencing role unresolved\",\n        \"Direct target genes not identified\"\n      ]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Resolved how TAF9B is incorporated into the transcriptional machinery and showed it occupies a genuine subunit role, establishing it as a TFIID/TFTC component that pairs with TAF6 via histone folds.\",\n      \"evidence\": \"MALDI mass spectrometry, reciprocal Co-IP, and in vitro/in vivo interaction assays\",\n      \"pmids\": [\"15899866\"],\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\n        \"Stoichiometry of TAF9 versus TAF9B within individual complexes not defined\",\n        \"No structural model of the TAF9B-containing complex\"\n      ]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Distinguished TAF9B from TAF9 functionally, showing it regulates a distinct gene set, is essential for viability, and uniquely stabilizes p53 during apoptosis.\",\n      \"evidence\": \"siRNA knockdown, gene expression microarray, and apoptosis assays\",\n      \"pmids\": [\"15899866\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\n        \"Molecular basis for differential gene selectivity versus TAF9 unknown\",\n        \"Mechanism of p53 stabilization not defined\",\n        \"Single-lab evidence for the apoptosis link\"\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Connected TAF9B to downstream survival signaling, implicating it in AKT/mTOR activation and Bcl-2/Bax-mediated apoptotic control.\",\n      \"evidence\": \"TAF9B overexpression/knockdown, dual-luciferase reporter, western blotting, and flow cytometry in osteosarcoma cells\",\n      \"pmids\": [\"33958878\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\n        \"Whether AKT/mTOR effects are direct transcriptional outputs of TAF9B unknown\",\n        \"Single cancer cell-type context\"\n      ]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Defined post-transcriptional control of TAF9B, showing microRNAs targeting its 3'UTR govern p53-dependent apoptosis and autophagy.\",\n      \"evidence\": \"miR-146a, miR-7-5p, and miR-199 overexpression/knockdown, dual-luciferase reporters, and knockout/functional readouts in cardiomyocytes and tumor cells\",\n      \"pmids\": [\"31511497\", \"33958878\", \"35873641\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\n        \"Endogenous regulatory hierarchy among the three microRNAs unresolved\",\n        \"Physiological conditions selecting each microRNA-TAF9B axis not defined\"\n      ]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Extended TAF9B function to specialized immune transcriptional programming, showing it is required for TH2 cell expansion and IL-4-dependent type II responses.\",\n      \"evidence\": \"Taf9b-deficient mouse T cells, adoptive transfer, and murine colitis/arthritis models\",\n      \"pmids\": [\"41671377\"],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\n        \"TAF9B target genes within the TH2 program not identified\",\n        \"Whether the role requires TFIID/TFTC incorporation not tested\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How TAF9B-containing complexes achieve gene selectivity distinct from TAF9, and how this links to its p53, AKT/mTOR, and TH2 roles, remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"\",\n      \"gaps\": [\n        \"No mechanistic link between TAF9B complex composition and its distinct target genes\",\n        \"No structural data on TAF9B-containing TFIID/TFTC\",\n        \"Direct transcriptional targets in p53 and immune programs unidentified\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [0, 1, 2]},\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [0, 2]}\n    ],\n    \"complexes\": [\"TFIID\", \"TFTC\"],\n    \"partners\": [\"TAF6\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":5,"faith_total":5,"faith_pct":100.0}}