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Showing TBPL2 — TRF3 is a alias.

TBPL2

TATA box-binding protein-like 2 · UniProt Q6SJ96

Length
343 aa
Mass
38.0 kDa
Annotated
2026-06-10
35 papers in source corpus 11 papers cited in narrative 11 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

TBPL2 (TRF3/TBP2) is a vertebrate-specific TBP paralog that substitutes for canonical TBP/TFIID to direct RNA Polymerase II transcription initiation in defined developmental contexts (PMID:14634207, PMID:33353944). Its C-terminal core domain is virtually identical to TBP, retaining residues for DNA binding and general transcription factor contacts, but TBPL2 does not assemble into a canonical TFIID complex; instead it forms a TBPL2/TFIIA complex that preferentially recognizes TATA-like core promoters and drives sharp, TSS-focused transcription, in contrast to TBP/TFIID at broad TATA-less promoters (PMID:14634207, PMID:33353944). In place of TFIID, TBPL2 partners selectively with TAF3 to form an alternative core-promoter recognition complex: in murine muscle differentiation this TBPL2/TAF3 complex mediates MyoD-dependent activation of the myogenin promoter required for terminal differentiation (PMID:18851836), and in zebrafish a selective Trf3–Taf3 interaction is required to occupy and activate the mespa promoter (PMID:19777587). In zebrafish, TBPL2 directly binds the mespa promoter and drives an ordered trf3→mespa→cdx4 transcription-factor pathway committing mesoderm to the haematopoietic lineage (PMID:18046332). TBPL2's principal physiological role is in the female germline, where it is essential for folliculogenesis, oocyte chromatin organization, and transcription of oocyte-specific genes through direct promoter binding, functioning mutually exclusively with TBP (PMID:19759265, PMID:19650908, PMID:33353944). Loss-of-function variants in human TBPL2 cause oocyte maturation defects and infertility (PMID:33893736, PMID:33966269).

Mechanistic history

Synthesis pass · year-by-year structured walk · 8 steps
  1. 2003 Medium

    Establishing whether TBPL2 is a genuine TBP-like factor that functions outside canonical TFIID was the first step in defining its mechanism.

    Evidence Sequence analysis, gel filtration, and nuclear localization/cell fractionation assays of vertebrate TRF3

    PMID:14634207

    Open questions at the time
    • Did not identify the actual complex TBPL2 assembles into
    • Functional transcriptional activity not demonstrated
    • No target genes defined
  2. 2004 Medium

    Determining whether TBPL2 retains TBP-like biochemical activity and is biologically required tied its TBP homology to genuine transcriptional and developmental function.

    Evidence TATA-box binding, TFIIA/TFIIB interaction assays, and morpholino knockdown with developmental phenotype in zebrafish

    PMID:15062100

    Open questions at the time
    • Direct promoter targets not identified
    • Mechanism distinguishing TBPL2 from TBP unresolved
    • Complex composition unknown
  3. 2006 Medium

    Showing that TBPL2 and TBP occupy distinct gene promoters established that they have non-redundant, promoter-selective roles rather than simple redundancy.

    Evidence ChIP, expression profiling, and cell-cycle nuclear localization assays in mouse ES cells and germ cells

    PMID:16721357

    Open questions at the time
    • What determines selective promoter recruitment unknown
    • No mechanistic complex defined
    • Functional consequence of differential occupancy not tested
  4. 2007 High

    Placing TBPL2 in an ordered developmental gene-regulatory pathway demonstrated it acts as a direct, lineage-instructive transcriptional activator in vivo.

    Evidence Morpholino knockdown, ChIP at the mespa promoter, mRNA rescue, and epistasis analysis in zebrafish haematopoiesis

    PMID:18046332

    Open questions at the time
    • Composition of the active TBPL2 complex at mespa not yet defined
    • Generalizability beyond haematopoiesis untested at this stage
  5. 2008 High

    Identifying TBPL2/TAF3 as a TFIID-replacing core-promoter recognition complex revealed the biochemical basis by which TBPL2 directs context-specific transcription.

    Evidence Purified reconstituted in vitro transcription, cell-based assays, and TAF3 domain mutagenesis at the myogenin promoter

    PMID:18851836

    Open questions at the time
    • Whether TBPL2/TAF3 operates in non-muscle tissues left open
    • Core promoter sequence preferences not yet mapped
  6. 2009 High

    Demonstrating selective Trf3–Taf3 interaction as essential for target activation and mutually exclusive TBP/TBPL2 germline functions unified the complex biochemistry with in vivo requirement.

    Evidence Reciprocal Co-IP, ChIP, structure-function mutagenesis and rescue in zebrafish; knockout mouse with reciprocal TBP-KO control, ChIP, and chromatin assays; lampbrush chromosome localization and altered-specificity reporter in Xenopus

    PMID:19650908 PMID:19759265 PMID:19777587

    Open questions at the time
    • Precise core-promoter architecture recognized by TBPL2 not yet resolved
    • Mechanism of TBP-to-TBPL2 factor switching only attributed to expression level
    • Genome-wide target set in oocytes incompletely defined
  7. 2020 High

    Defining the TBPL2/TFIIA complex and its preference for TATA-like, sharp-TSS promoters established the molecular logic distinguishing TBPL2-driven from TBP/TFIID-driven transcription in oocytes.

    Evidence Biochemical fractionation, Co-IP for TFIIA, CAGE/TSS mapping, and transcriptome analysis in mouse oocytes

    PMID:33353944

    Open questions at the time
    • Structural basis of TATA-like promoter selectivity not solved
    • How TFIIA versus TAF3 partnering is selected in different contexts unresolved
  8. 2021 Medium

    Linking TBPL2 loss-of-function variants to human oocyte maturation arrest connected the mechanistic model to disease causation in the female germline.

    Evidence Whole-exome and Sanger sequencing, minigene splicing assay, single-oocyte RNA-seq, and a transcription initiation functional assay in infertile patients

    PMID:33893736 PMID:33966269

    Open questions at the time
    • Direct protein-level functional assays for the variants limited
    • How variants alter complex assembly or promoter selectivity not tested

Open questions

Synthesis pass · forward-looking unresolved questions
  • How TBPL2 partner choice (TFIIA versus TAF3) and core-promoter architecture are integrated to specify its distinct developmental and germline transcription programs remains unresolved.
  • No structural model of TBPL2 on TATA-like promoters
  • Mechanism selecting TFIIA- versus TAF3-containing TBPL2 complexes in a given cell type unknown
  • Complete genome-wide TBPL2 target catalog across tissues incomplete

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 2
Localization
GO:0005634 nucleus 2 GO:0000228 nuclear chromosome 1
Pathway
R-HSA-74160 Gene expression (Transcription) 3 R-HSA-1266738 Developmental Biology 2 R-HSA-1474165 Reproduction 2
Partners
GTF2A1GTF2BMYOD1TAF3TBP
Complex memberships
TBPL2/TAF3 complexTBPL2/TFIIA complex

Evidence

Reading pass · 11 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2003 TRF3 (TBPL2) is a vertebrate-specific nuclear protein with a C-terminal core domain virtually identical to TBP, including all residues involved in DNA binding and interaction with general transcription factors. Gel filtration analysis showed the native molecular weight of TRF3 is substantially less than that of TFIID, indicating it does not assemble into a canonical TFIID complex. After mitosis, nuclear reimport of TRF3 occurs subsequent to TBP and other basal transcription factors. Gel filtration, nuclear localization assays, sequence analysis, cell fractionation Proceedings of the National Academy of Sciences of the United States of America Medium 14634207
2004 Zebrafish TBP2 binds the TATA box, interacts with TFIIA and TFIIB (similarly to TBP), and can mediate RNA Pol II transcription initiation. Knockdown of zebrafish TBP2 causes developmental patterning defects, demonstrating its requirement for embryonic development. DNA binding assay, protein interaction assays (TFIIA/TFIIB), morpholino knockdown with phenotypic readout Current biology : CB Medium 15062100
2007 Zebrafish Trf3 (TBPL2) is required for haematopoiesis by directly binding the mespa promoter (ChIP) and driving its transcription. Epistasis analysis established an ordered trf3→mespa→cdx4 transcription factor pathway required for commitment of mesoderm to the haematopoietic lineage. Injection of mespa mRNA rescued the Trf3-depleted phenotype, confirming mespa as the single essential Trf3 target gene. Morpholino knockdown, chromatin immunoprecipitation (ChIP), mRNA rescue, epistasis analysis Nature High 18046332
2008 In murine muscle differentiation, TRF3 (TBPL2) forms a complex with TAF3 that replaces the canonical TFIID to drive MyoD-dependent transcription initiation at the Myogenin promoter. A domain of TAF3 mediates coactivator functions targeted by MyoD. This core promoter recognition complex switch is required for terminal muscle differentiation. Purified reconstituted in vitro transcription system, cell-based transcription assays, domain mutagenesis Molecular cell High 18851836
2009 Zebrafish Taf3 selectively interacts with Trf3 (TBPL2) but not with Tbp. A Trf3 mutant that disrupts the Taf3 interaction fails to support mespa transcription, early development, and haematopoiesis. Both Trf3 and Taf3 are bound to the mespa promoter by ChIP, establishing that selective Trf3-Taf3 interaction is required for target gene activation. Co-immunoprecipitation, ChIP, morpholino knockdown, structure-function mutagenesis, rescue assays Developmental dynamics : an official publication of the American Association of Anatomists High 19777587
2009 TBP2 (TBPL2) is essential for female germ cell development in mice. TBP2-deficient female mice are sterile due to defective folliculogenesis, altered chromatin organization, and transcriptional misregulation of oocyte-specific genes. TBP2 directly binds promoters of misregulated genes by ChIP. Conversely, TBP ablation in the female germline results in normal ovulation, demonstrating mutually exclusive functions of TBP and TBP2 in oocytes. Knockout mouse generation, ChIP, transcriptional analysis, chromatin organization assays Genes & development High 19759265
2009 In Xenopus oocytes, TBP2 localizes to transcriptionally active loops of lampbrush chromosomes, promotes RNA Pol II transcription in vivo using an altered-specificity mutant reporter system, and is proteolytically degraded upon meiotic maturation (germinal vesicle breakdown). TBP can functionally replace TBP2 when ectopically expressed in oocytes, showing factor switching is driven by expression level changes. Immunofluorescence/lampbrush chromosome localization, altered-specificity mutant reporter transcription assay, ectopic expression rescue BMC biology High 19650908
2006 TRF3 (TBPL2) is co-expressed with TBP in meiotic oocytes and early mouse embryos. ChIP in mouse ES cells showed that different gene promoters selectively recruit TRF3 or TBP, indicating differential promoter occupancy. TRF3 is slightly delayed relative to TBP in nuclear re-entry after mitosis. Chromatin immunoprecipitation (ChIP), expression analysis, cell cycle synchronization and nuclear localization assay Cell research Medium 16721357
2020 In mouse oocytes, TBPL2 does not assemble into a canonical TFIID complex. TBPL2 forms a complex with TFIIA and mediates transcription preferentially from TATA-like motif-containing core promoters with sharp transcription start site (TSS) architecture, in contrast to TBP/TFIID-driven TATA-less promoters with broader TSS profiles. TBPL2 is required for transcription of oocyte-expressed genes including mRNA surveillance genes and specific endogenous retroviral elements. Biochemical fractionation (showing no canonical TFIID), TSS mapping (CAGE/cap analysis), transcriptome analysis, Co-IP for TFIIA interaction Nature communications High 33353944
2021 A homozygous splicing variant (c.788+3A>G) in TBPL2 disrupts TBPL2 mRNA integrity and is associated with oocyte maturation defects in humans. Single-oocyte transcriptome sequencing of affected oocytes showed widespread downregulation of vital oocyte maturation and fertilization genes, consistent with TBPL2's role as a transcriptional activator of these targets. Whole-exome sequencing, Sanger sequencing, minigene assay, single-oocyte RNA sequencing Human reproduction (Oxford, England) Medium 33893736
2021 A homozygous missense mutation (c.895T>C; p.C299R) in TBPL2 impairs the transcription initiation function of the protein and is associated with oocyte maturation arrest and degeneration in two infertile sisters. Whole-exome sequencing, Sanger sequencing, functional transcription initiation assay Clinical genetics Medium 33966269

Source papers

Stage 0 corpus · 35 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
1993 Cloning and characterization of Neisseria meningitidis genes encoding the transferrin-binding proteins Tbp1 and Tbp2. Gene 134 8344530
2008 MyoD targets TAF3/TRF3 to activate myogenin transcription. Molecular cell 127 18851836
2010 Disruption of TBP-2 ameliorates insulin sensitivity and secretion without affecting obesity. Nature communications 103 21119640
2011 TXNIP (VDUP-1, TBP-2): a major redox regulator commonly suppressed in cancer by epigenetic mechanisms. The international journal of biochemistry & cell biology 96 21964212
2009 TBP2 is essential for germ cell development by regulating transcription and chromatin condensation in the oocyte. Genes & development 79 19759265
2004 TBP2, a vertebrate-specific member of the TBP family, is required in embryonic development of zebrafish. Current biology : CB 72 15062100
2007 Initiation of zebrafish haematopoiesis by the TATA-box-binding protein-related factor Trf3. Nature 64 18046332
2003 TRF3, a TATA-box-binding protein-related factor, is vertebrate-specific and widely expressed. Proceedings of the National Academy of Sciences of the United States of America 62 14634207
1994 Characterization of a highly structured domain in Tbp2 from Neisseria meningitidis involved in binding to human transferrin. Journal of bacteriology 40 7928990
2021 Endogenous tRNA-derived small RNA (tRF3-Thr-AGT) inhibits ZBP1/NLRP3 pathway-mediated cell pyroptosis to attenuate acute pancreatitis (AP). Journal of cellular and molecular medicine 35 34643045
2020 TBPL2/TFIIA complex establishes the maternal transcriptome through oocyte-specific promoter usage. Nature communications 35 33353944
2018 The Function of Thioredoxin-Binding Protein-2 (TBP-2) in Different Diseases. Oxidative medicine and cellular longevity 35 29854083
2012 Deficiency of thioredoxin binding protein-2 (TBP-2) enhances TGF-β signaling and promotes epithelial to mesenchymal transition. PloS one 30 22768160
1995 Diversity of the transferrin-binding protein Tbp2 of Neisseria meningitidis. Gene 28 7789801
2024 tRF3-IleAAT reduced extracellular matrix synthesis in diabetic kidney disease mice by targeting ZNF281 and inhibiting ferroptosis. Acta pharmacologica Sinica 27 38286833
2009 Selective interaction between Trf3 and Taf3 required for early development and hematopoiesis. Developmental dynamics : an official publication of the American Association of Anatomists 27 19777587
2009 TBP2 is a substitute for TBP in Xenopus oocyte transcription. BMC biology 24 19650908
2021 A homozygous variant in TBPL2 was identified in women with oocyte maturation defects and infertility. Human reproduction (Oxford, England) 23 33893736
2007 Regulation of the bioavailability of thioredoxin in the lens by a specific thioredoxin-binding protein (TBP-2). Experimental eye research 21 17603038
1993 Purification of the Neisseria meningitidis transferrin binding protein-2 (TBP2) to homogeneity using column chromatography. FEMS microbiology letters 16 8339907
1995 Variable sequences in a mosaic-like domain of meningococcal tbp2 encode immunoreactive epitopes. FEMS microbiology letters 15 7590185
2020 miR-93, miR-373, and miR-17-5p Negatively Regulate the Expression of TBP2 in Lung Cancer. Frontiers in oncology 14 32426273
2006 Thioredoxin-binding protein-2 (TBP-2): its potential roles in the aging process. BioFactors (Oxford, England) 14 17012763
2006 Regulated expression of TATA-binding protein-related factor 3 (TRF3) during early embryogenesis. Cell research 13 16721357
2021 A homozygous missense mutation in TBPL2 is associated with oocyte maturation arrest and degeneration. Clinical genetics 11 33966269
1996 Molecular characterization of hybrid Tbp2 proteins from Neisseria meningitidis. Molecular microbiology 11 8821945
2009 TBP2 is a general transcription factor specialized for female germ cells. Journal of biology 9 19951399
2021 Changes in the Expression of TBP-2 in Response to Histone Deacetylase Inhibitor Treatment in Human Endometrial Cells. International journal of molecular sciences 8 33572677
2007 Genomics, evolution, and expression of TBPL2, a member of the TBP family. DNA and cell biology 7 17570761
2023 Compound heterozygous mutations in TBPL2 were identified in an infertile woman with impaired ovarian folliculogenesis. Journal of assisted reproduction and genetics 6 37804378
1994 Reliability of laboratory models in the analysis of TBP2 and other meningococcal antigens. FEMS immunology and medical microbiology 6 7866351
2024 Redoxisome Update: TRX and TXNIP/TBP2-Dependent Regulation of NLRP-1/NLRP-3 Inflammasome. Antioxidants & redox signaling 5 38386512
2020 Genome sequence analysis of the temperate bacteriophage TBP2 of the solvent producer Clostridium saccharoperbutylacetonicum N1-4 (HMT, ATCC 27021). FEMS microbiology letters 5 32614389
2016 TBP2 gene may not be associated with primary ovarian insufficiency. Climacteric : the journal of the International Menopause Society 2 27642674
1997 Cloning and sequencing of the gene encoding the outer-membrane protein Tbp1 from Actinobacillus pleuropneumoniae. Expression of Tbp1 and Tbp2. Behring Institute Mitteilungen 1 9382765

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