Affinage

TAF4B

Transcription initiation factor TFIID subunit 4B · UniProt Q92750

Length
862 aa
Mass
91.1 kDa
Annotated
2026-06-10
23 papers in source corpus 20 papers cited in narrative 20 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 6/6 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

TAF4B is a gonadal-enriched, cell-type-selective subunit of the TFIID general transcription factor complex that confers promoter and activator specificity to germline and gonadal gene expression programs (PMID:18206971, PMID:27341508). Incorporation of TAF4b into TFIID induces an open conformation at the lobe involved in TFIIA and activator contacts, a structural change that directs activator-dependent transcription and supports synergy between c-Jun and Sp1 at TAF4b target promoters (PMID:18206971). Rather than canonical TATA boxes, TAF4b directly occupies proximal promoters enriched for Sp/Klf and NFY motifs, including meiosis and oogenesis regulators (Stra8, Dazl, Figla, Nobox) and chromatin-remodeling and DNA-repair genes (PMID:27341508, PMID:35043944). Through these activities TAF4b is required cell-autonomously for spermatogonial stem cell self-renewal and gonocyte expansion (PMID:15774719, PMID:25727968), prospermatogonial entry into quiescence (PMID:37900284), oocyte meiotic prophase I progression and double-strand-break repair [PMID:27341508, PMID:bio_10.1101_2025.01.06.631470], establishment of the primordial follicle reserve by limiting caspase-dependent oocyte loss (PMID:24836512), and granulosa cell survival and hormonal responsiveness (PMID:16473943, PMID:17207475). It cooperates with sequence-specific factors including c-Jun, Sp1, and the pluripotency factor Oct4, and partners with the zinc-finger protein ZFP628 in spermiogenesis gene regulation (PMID:18206971, PMID:23350932, PMID:31932482). TAF4b expression is itself induced by estrogen via nuclear estrogen receptors, by FSH, and by MYC through a non-canonical E-box (PMID:24068106, PMID:17888567, PMID:19020761).

Mechanistic history

Synthesis pass · year-by-year structured walk · 19 steps
  1. 2005 High

    Established that TAF4b is required for the male germline, answering whether a gonad-enriched TFIID subunit has a non-redundant developmental function.

    Evidence Taf4b-null mouse genetics with histology and spermatogonial marker RT-PCR

    PMID:15774719

    Open questions at the time
    • Did not define direct promoter targets
    • Mechanism of stem cell maintenance not resolved at the molecular level
  2. 2005 High

    Extended the requirement to the female germline across developmental stages, showing TAF4b is needed for follicle formation, oocyte maturation, and early embryonic cleavage.

    Evidence Taf4b-null mouse genetics with ovulation, IVF, and two-cell arrest assays

    PMID:16289522

    Open questions at the time
    • Somatic vs germ-cell-autonomy not separated
    • Direct transcriptional targets unknown
  3. 2006 High

    Placed TAF4b in a defined regulatory pathway by showing it controls granulosa-cell c-jun expression and co-regulates ovary-selective promoters, and that it is required for granulosa survival and hormonal proliferation.

    Evidence Taf4b-null ovaries, ChIP, reporter assays, TUNEL, and FSH/estrogen stimulation

    PMID:16473943 PMID:17207475

    Open questions at the time
    • Whether c-Jun cooperation is direct at TFIID was not structurally resolved
    • Range of ovary-selective promoters not genome-wide defined
  4. 2008 High

    Provided the structural mechanism: TAF4b incorporation reshapes TFIID into an open conformation that enables selective activator interactions and promoter recognition.

    Evidence Electron microscopy single-particle reconstruction of 4b/4-IID with in vitro transcription and mass spectrometry

    PMID:18206971

    Open questions at the time
    • Resolution limited to 35 Å
    • Did not map which in vivo promoters use this conformation
  5. 2008 Medium

    Identified an upstream activator of TAF4b, showing MYC induces TAF4b through a non-canonical E-box, linking it to oncogenic transcriptional control.

    Evidence Promoter-reporter assays, E-box mutagenesis, and EMSA

    PMID:19020761

    Open questions at the time
    • Reporter-based; in vivo MYC occupancy not shown
    • Physiological context of MYC induction not established
  6. 2007 Medium

    Connected hormonal signaling to TAF4b function by showing FSH induces TAF4b via PKA/PI3K/MAPK and that TAF4b mediates FSH induction of the IGFBP-3 promoter.

    Evidence TAF4b overexpression and co-transfection reporter assays in porcine granulosa cells

    PMID:17888567

    Open questions at the time
    • Overexpression-based; endogenous requirement not tested
    • Single target promoter examined
  7. 2009 Medium

    Demonstrated TAF4b loss causes premature reproductive senescence and linked it to posttranscriptional regulators, broadening its role beyond canonical transcription.

    Evidence Taf4b-null mouse genome-wide microarray profiling with RT-PCR validation

    PMID:19684329

    Open questions at the time
    • Mov10l1 link is correlative
    • Direct vs indirect targets not distinguished
  8. 2010 Medium

    Showed TAF4b–c-Jun cooperation operates outside the gonad, co-occupying the integrin alpha6 promoter to influence migration and EMT in colon cancer cells.

    Evidence Endogenous reciprocal Co-IP, ChIP, and migration assays

    PMID:20353996

    Open questions at the time
    • Single lab and cell context
    • Generality to other tumors not tested
  9. 2013 Medium

    Revealed a pluripotency role: TAF4b, but not TAF4, interacts with Oct4 and cooperates to regulate target genes, supporting ESC self-renewal.

    Evidence shRNA knockdown in ESC, Co-IP, alkaline phosphatase and gene expression assays

    PMID:23350932

    Open questions at the time
    • Co-IP interaction not structurally mapped
    • Direct vs TFIID-mediated Oct4 cooperation not resolved
  10. 2013 Medium

    Identified estrogen as a direct upstream inducer of TAF4b acting through nuclear estrogen receptors.

    Evidence qRT-PCR, western blot, in vivo estrogen treatment, and ER blockade in granulosa cells

    PMID:24068106

    Open questions at the time
    • Direct ER binding to the TAF4b promoter not mapped
    • Single-lab pharmacological evidence
  11. 2014 Medium

    Established that TAF4b protects the primordial follicle reserve by limiting caspase-dependent oocyte loss during cyst breakdown.

    Evidence Taf4b-null neonatal ovaries, activated caspase-3 staining, and ZVAD-FMK rescue in culture

    PMID:24836512

    Open questions at the time
    • Transcriptional targets driving apoptosis not identified
    • Upstream survival pathway not defined
  12. 2015 High

    Proved TAF4b function in spermatogonial stem cells is germ-cell-autonomous and biases the self-renewal/differentiation balance.

    Evidence Taf4b-null mice with germ cell transplantation rescue and spermatogonial marker immunostaining

    PMID:25727968

    Open questions at the time
    • Direct gene targets in SSCs not mapped
    • Molecular self-renewal mechanism not resolved
  13. 2016 High

    Defined direct promoter targets genome-wide, showing TAF4b occupies and is required for meiosis and oogenesis regulators and proper prophase I progression.

    Evidence ChIP-seq, RNA-seq in Taf4b-null embryonic ovaries, and SYCP3 synapsis staining

    PMID:27341508

    Open questions at the time
    • Mechanism of promoter selectivity not yet explained
    • Human relevance only inferred by comparative transcriptomics
  14. 2020 High

    Identified ZFP628 as a direct domain-mapped partner of TAF4b, implicating the complex in spermiogenesis gene regulation.

    Evidence Two-hybrid, deletion mapping, testis-extract Co-IP, and ZFP628 CRISPR KO with spermiogenesis gene RT-qPCR

    PMID:31932482

    Open questions at the time
    • Whether the complex acts through TFIID not shown
    • Direct promoter occupancy of the TAF4b-ZFP628 complex not mapped
  15. 2022 Medium

    Explained the alternative promoter logic, showing TAF4b targets are enriched for Sp/Klf and NFY motifs rather than TATA boxes and govern chromatin and X-linked programs in oocytes.

    Evidence CUT&RUN chromatin mapping with RNA-seq and motif analysis in oocytes

    PMID:35043944

    Open questions at the time
    • Direct binding to Sp/Klf/NFY factors not demonstrated
    • Single-lab dataset
  16. 2023 Medium

    Showed TAF4b drives the prospermatogonial mitotic-to-quiescent transition by regulating chromatin and cell-cycle programs.

    Evidence Taf4b-null mice with RNA-seq, CUT&RUN, and PCNA immunostaining

    PMID:37900284

    Open questions at the time
    • Direct vs indirect cell-cycle targets not separated
    • Mechanism of quiescence entry incompletely defined
  17. 2024 Medium

    Placed TAF4B in a human SSC regulatory axis downstream of EEF1B2 controlling proliferation and self-renewal.

    Evidence shRNA knockdown, RNA-seq, and TAF4B rescue with proliferation assays in human SSC lines

    PMID:39281470

    Open questions at the time
    • How EEF1B2 regulates TAF4B mechanistically unknown
    • Single-lab human cell line evidence
  18. 2025 Medium

    Refined the oocyte phenotype to a defect in the pachytene-to-diplotene transition and DSB repair, distinguishing meiotic entry from later progression.

    Evidence Taf4b-null fetal oocyte time-course transcriptomics and γH2AX cytology (preprint)

    PMID:bio_10.1101_2025.01.06.631470

    Open questions at the time
    • Preprint, not yet peer-reviewed
    • Direct DSB-repair gene targets not mechanistically validated
  19. 2025 Medium

    Extended TAF4B requirement beyond the gonad to hematopoiesis, showing lineage- and stage-dependent effects on erythroid and NK differentiation.

    Evidence shRNA knockdown in human cord blood HSPCs with CFU assays, directed differentiation, and flow cytometry

    PMID:41447882

    Open questions at the time
    • No mechanistic pathway placement beyond phenotype
    • Direct targets in HSPCs not identified

Open questions

Synthesis pass · forward-looking unresolved questions
  • How TAF4b achieves its TATA-independent promoter selectivity—whether through direct contacts with Sp/Klf and NFY factors or via the TFIID open conformation—remains the central unresolved mechanistic question.
  • No demonstrated direct interaction between TAF4b and Sp/Klf or NFY proteins
  • No high-resolution structure of TAF4b-TFIID engaging a target promoter
  • Human in vivo germline requirement not directly tested

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0140110 transcription regulator activity 4 GO:0003677 DNA binding 2 GO:0140223 general transcription initiation factor activity 1
Localization
GO:0000228 nuclear chromosome 2 GO:0005634 nucleus 1
Pathway
R-HSA-1474165 Reproduction 4 R-HSA-1266738 Developmental Biology 3 R-HSA-74160 Gene expression (Transcription) 2
Partners
C-JUNOCT4SP1ZFP628
Complex memberships
TFIID

Evidence

Reading pass · 20 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2008 TAF4b incorporation into TFIID induces an open conformation at the lobe involved in TFIIA and putative activator interactions, as revealed by 35 Å electron microscopy single-particle reconstruction of a TAF4b/TAF4-containing TFIID (4b/4-IID). This structural change correlates with differential activator-dependent transcription and promoter recognition, specifically directing transcriptional synergy between c-Jun and Sp1 at a TAF4b target promoter. Electron microscopy and single-particle reconstruction; in vitro transcription assays; mass spectrometry-based complex characterization Molecular cell High 18206971
2006 TAF4b controls granulosa-cell-specific expression of c-jun, and together TAF4b and c-Jun regulate transcription of ovary-selective promoters. Loss of TAF4b in ovarian granulosa cells disrupts cellular morphologies and interactions during follicle growth. Taf4b-null mouse ovaries; reporter assays; chromatin immunoprecipitation (ChIP); immunofluorescence; cell morphology analysis Proceedings of the National Academy of Sciences of the United States of America High 16473943
2005 TAF4b is required for maintenance of spermatogenesis in mouse: Taf4b-null males become infertile by 3 months, show impaired gonocyte proliferation at postnatal day 3, and reduced expression of spermatogonial stem cell markers c-Ret, Plzf, and Stra8. Taf4b-null mouse genetics; histology; immunofluorescence; RT-PCR for marker gene expression Genes & development High 15774719
2006 TAF4b is expressed in granulosa cells of the ovarian follicle and is required for granulosa cell survival and proliferative response to hormonal stimuli (FSH and estrogen). TAF4b-null ovaries show increased follicle apoptosis and reduced follicle numbers. Taf4b-null mouse genetics; immunofluorescence/immunohistochemistry; TUNEL/apoptosis assays; hormone stimulation experiments; follicle counting Developmental biology High 17207475
2005 TAF4b-null female mice display defects in early follicle formation, oocyte maturation (impaired GVBD and polar body extrusion), and zygotic cleavage. TAF4b is required for proper expression of only some somatic cell markers (Foxl2 reduced; granulosa differentiation markers largely normal). Taf4b-null mouse genetics; histology; ovulation assays; in vitro fertilization; two-cell arrest analysis Developmental biology High 16289522
2010 TAF4b and c-Jun colocalize and interact in the nucleus of colon adenocarcinoma cells, and together synergistically occupy the promoter of integrin alpha6, regulating its expression and thereby altering cell migration and EMT properties. Co-immunoprecipitation of endogenous proteins; chromatin immunoprecipitation (ChIP); co-localization by immunofluorescence; reporter/migration assays Molecular cancer research : MCR Medium 20353996
2013 TAF4b is highly expressed in mouse embryonic stem cells (ESC) and is downregulated upon differentiation. TAF4b knockdown reduces self-renewal marker alkaline phosphatase and impairs ESC proliferation. TAF4b, but not TAF4, directly interacts with Oct4, and TAF4b cooperates with Oct4 to regulate target genes including Sohlh2 and Yes1. shRNA knockdown in ESC; alkaline phosphatase assay; co-immunoprecipitation (TAF4b-Oct4); gene expression analysis; cell cycle assays Genes to cells : devoted to molecular & cellular mechanisms Medium 23350932
2007 TAF4b mediates FSH stimulation of the IGFBP-3 promoter in porcine granulosa cells: FSH stimulates TAF4b expression via PKA/PI3K/MAPK pathways, and TAF4b overexpression mimics and enhances FSH induction of IGFBP-3 reporter activity through the TBP site. TAF4b cDNA cloning; co-transfection reporter assays in granulosa cells; RT-PCR for FSH-induced TAF4b expression Molecular and cellular endocrinology Medium 17888567
2009 TAF4b-deficient female mice exhibit premature reproductive senescence with follicle depletion completed by 16 weeks. Genome-wide expression profiling of 3-week Taf4b-null ovaries shows decreased Mov10l1 expression (a putative germline RNA helicase), linking TAF4b to posttranscriptional control of ovarian gene expression. Taf4b-null mouse genetics; microarray gene expression profiling; RT-PCR validation; histological analysis; estrous cycle monitoring Biology of reproduction Medium 19684329
2013 TAF4b mRNA and protein levels in the mouse ovary and granulosa cells are increased within hours of exposure to 17β-estradiol or diethylstilbestrol, and this response is mediated via nuclear estrogen receptors both in vivo and in a granulosa cancer cell line. qRT-PCR and western blot; in vivo estrogen treatment; nuclear ER blockade experiments; granulosa cancer cell line (NT-1) Biology of reproduction Medium 24068106
2014 TAF4b is required for initial establishment of the primordial follicle reserve: TAF4b-deficient mouse ovaries at birth show delayed germ cell cyst breakdown and excessive oocyte loss via caspase-dependent apoptosis. Pan-caspase inhibitor ZVAD-FMK suppresses this excessive oocyte loss in cultured neonatal TAF4b-deficient ovaries. Taf4b-null mouse genetics; Activated Caspase 3 immunostaining; neonatal ovary culture with ZVAD-FMK inhibitor; follicle counting Developmental biology Medium 24836512
2015 TAF4b is required for spermatogonial stem cell (SSC) development: Taf4b-deficient mice show reduced late embryonic gonocyte pool, deficient postnatal expansion, delayed meiosis initiation, and aberrant GFRα1+ spermatogonial chain formation with increased differentiation at the expense of self-renewal. Germ cell transplantation into TAF4b-deficient host testes established a germ-cell-autonomous function. Taf4b-null mouse genetics; germ cell transplantation assay; immunostaining for spermatogonial markers (GFRα1, PLZF); histological analysis; chain length quantification Stem cells (Dayton, Ohio) High 25727968
2016 TAF4b directly occupies proximal promoters of meiosis and oogenesis regulators (Stra8, Dazl, Figla, Nobox) and is required for their expression. Taf4b-deficient mouse oocytes show severe deficits in meiotic prophase I progression and asynapsis. ChIP-seq (TAF4b promoter occupancy); RNA-seq in Taf4b-null embryonic ovaries; immunofluorescence for synapsis (SYCP3); comparative transcriptomics with human fetal ovary PLoS genetics High 27341508
2020 TAF4b directly interacts with the zinc-finger protein ZFP628 via discrete protein domains mapped by deletion analysis. This interaction is supported by co-immunoprecipitation from testis-derived protein extracts. ZFP628 deficiency (by CRISPR-Cas9) causes postmeiotic round spermatid arrest with reduced Tnp1, Tnp2, Prm1, and Prm2 mRNA, implicating the TAF4b-ZFP628 complex in spermiogenesis gene regulation. Two-hybrid screening; deletion analysis; in vitro interaction assays; co-immunoprecipitation from testis extracts; CRISPR-Cas9 KO; RT-qPCR for spermiogenesis genes; histology Molecular and cellular biology High 31932482
2008 MYC directly induces TAF4b expression through a non-canonical E-box (CGCGTG) in a conserved region of the TAF4b promoter, distinct from canonical E-boxes that also bind USF. Mutation of the non-canonical E-box to canonical abolishes specificity for MYC. Transcription start site mapping; promoter-reporter assays; E-box mutagenesis; electrophoretic mobility shift assays International journal of oncology Medium 19020761
2022 TAF4b occupies promoters of chromatin remodeling and DNA repair genes in mouse oocytes (mapped by CUT&RUN), with TAF4b target gene promoters enriched for Sp/Klf family and NFY motifs rather than TATA-box motifs, suggesting an alternative mode of promoter interaction. Taf4b-deficient oocytes show dysregulated meiotic, chromatin organization, and X-linked gene expression programs. CUT&RUN (chromatin mapping); RNA-seq in Taf4b-deficient oocytes; gene ontology and motif analysis Development (Cambridge, England) Medium 35043944
2023 TAF4b is elevated during the transition of mitotic-to-quiescent prospermatogonia, and TAF4b-deficient prospermatogonia are delayed in entry into quiescence. TAF4b directly and indirectly regulates chromatin and cell cycle gene expression programs during prospermatogonial quiescence, as shown by elevated PCNA staining in Taf4b-deficient cells. Taf4b-null mouse genetics; RNA-seq; chromatin mapping (CUT&RUN); gene ontology/network analysis; immunostaining for PCNA Frontiers in cell and developmental biology Medium 37900284
2024 EEF1B2 knockdown in human spermatogonial stem cell lines reduces TAF4B expression, and replenishing TAF4B rescues impaired proliferation and self-renewal, placing TAF4B downstream of EEF1B2 in a regulatory axis controlling human SSC proliferation. shRNA knockdown; RNA sequencing; TAF4B rescue overexpression; CCK8/EdU proliferation assays; western blot for self-renewal markers Heliyon Medium 39281470
2025 Taf4b-deficient mouse fetal oocytes enter meiosis I in a timely manner but exhibit compromised pachytene-to-diplotene transition and reduced ability to repair double-strand DNA breaks. Between E16.5 and E18.5, Taf4b-deficient oocytes fail to coordinate reduction of meiotic gene expression with induction of oocyte differentiation genes. Taf4b-null mouse genetics; transcriptional profiling at multiple embryonic time points; immunostaining for meiotic stages and DNA damage markers (e.g., γH2AX) bioRxivpreprint Medium bio_10.1101_2025.01.06.631470
2025 TAF4B knockdown in human cord blood HSPCs reduces CFU-Mix output and total erythroid cell numbers (with decreased HBB transcripts) and reduces CD16+ NK cell proportion (with reduced TBX21), but does not affect monocytic differentiation, demonstrating lineage- and stage-dependent sensitivity to TAF4B perturbation. shRNA knockdown in cord blood Lin-CD34+ HSPCs; colony-forming unit assays; directed differentiation cultures; flow cytometry; RT-qPCR Biochemical and biophysical research communications Medium 41447882

Source papers

Stage 0 corpus · 23 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2005 Maintenance of spermatogenesis requires TAF4b, a gonad-specific subunit of TFIID. Genes & development 178 15774719
2014 Truncating mutations in TAF4B and ZMYND15 causing recessive azoospermia. Journal of medical genetics 93 24431330
2006 Ovarian granulosa cell survival and proliferation requires the gonad-selective TFIID subunit TAF4b. Developmental biology 54 17207475
2008 Structural changes in TAF4b-TFIID correlate with promoter selectivity. Molecular cell 53 18206971
2005 TAF4b, a TBP associated factor, is required for oocyte development and function. Developmental biology 47 16289522
2014 TAF4b promotes mouse primordial follicle assembly and oocyte survival. Developmental biology 36 24836512
2015 TAF4b is required for mouse spermatogonial stem cell development. Stem cells (Dayton, Ohio) 32 25727968
2009 Accelerated ovarian aging in the absence of the transcription regulator TAF4B in mice. Biology of reproduction 32 19684329
2006 Cell-type-selective induction of c-jun by TAF4b directs ovarian-specific transcription networks. Proceedings of the National Academy of Sciences of the United States of America 31 16473943
2016 TAF4b Regulates Oocyte-Specific Genes Essential for Meiosis. PLoS genetics 28 27341508
2021 Circular RNA TAF4B Promotes Bladder Cancer Progression by Sponging miR-1298-5p and Regulating TGFA Expression. Frontiers in oncology 25 34322376
2022 TAF4b transcription networks regulating early oocyte differentiation. Development (Cambridge, England) 13 35043944
2020 ZFP628 Is a TAF4b-Interacting Transcription Factor Required for Mouse Spermiogenesis. Molecular and cellular biology 12 31932482
2010 TAF4b and Jun/activating protein-1 collaborate to regulate the expression of integrin alpha6 and cancer cell migration properties. Molecular cancer research : MCR 12 20353996
2013 TAF4b and TAF4 differentially regulate mouse embryonic stem cells maintenance and proliferation. Genes to cells : devoted to molecular & cellular mechanisms 10 23350932
2007 The TATA binding protein associated factor 4b (TAF4b) mediates FSH stimulation of the IGFBP-3 promoter in cultured porcine ovarian granulosa cells. Molecular and cellular endocrinology 8 17888567
2013 Estrogen responsiveness of the TFIID subunit TAF4B in the normal mouse ovary and in ovarian tumors. Biology of reproduction 5 24068106
2023 Transcription and chromatin regulation by TAF4b during cellular quiescence of developing prospermatogonia. Frontiers in cell and developmental biology 4 37900284
2008 Expression of the TAF4b gene is induced by MYC through a non-canonical, but not canonical, E-box which contributes to its specific response to MYC. International journal of oncology 4 19020761
2024 EEF1B2 regulates the proliferation and apoptosis of human spermatogonial stem cell lines through TAF4B. Heliyon 1 39281470
2024 Overexpression of TAF4B Promoted the Proliferation of Undifferentiated Spermatogonia in Cattleyak In Vitro. Reproduction in domestic animals = Zuchthygiene 1 39494734
2025 TAF4B knockdown differentially affects erythroid and natural killer cells but not monocytic differentiation from human cord blood HSPCs. Biochemical and biophysical research communications 0 41447882
2024 Circular RNA TAF4B targeting MFN2 accelerates cell growth in bladder cancer through p27 depression and AKT activation. Frontiers in immunology 0 39430741

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