Affinage

TBX15

T-box transcription factor TBX15 · UniProt Q96SF7

Length
602 aa
Mass
65.8 kDa
Annotated
2026-04-28
34 papers in source corpus 19 papers cited in narrative 19 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

TBX15 is a T-box transcription factor that controls mesodermal patterning, metabolic fiber-type specification, and adipocyte differentiation by binding T half-site DNA sequences as homo- or heterodimers and functioning as both a transcriptional repressor (via Groucho corepressors) and activator of specific target genes (PMID:17584735, PMID:36124393). In skeletal development, TBX15 promotes proliferation of chondrocytes and mesenchymal precursor cells and patterns the shoulder girdle synergistically with Gli3 and Alx4 (PMID:15652702, PMID:15728667); loss-of-function mutations in human TBX15 cause Cousin syndrome through accelerated degradation of truncated protein products (PMID:19068278). In muscle, TBX15 is selectively expressed in glycolytic myofibers and its ablation shifts fiber identity toward oxidative fibers via AMPK activation and reduced Igf2 expression, while in adipocytes it directly binds the Prdm16 promoter to drive browning and thermogenesis and more broadly suppresses mitochondrial respiration and promotes glycolytic metabolism (PMID:26299309, PMID:31352005, PMID:21282637, PMID:28847884). TBX15 also functions as a trans-regulatory hub in human preadipocytes, controlling a network including PPARG and KLF15 that is linked to abdominal obesity (PMID:34340684).

Mechanistic history

Synthesis pass · year-by-year structured walk · 13 steps
  1. 2004 High

    Establishing that Tbx15 provides positional identity in dorsal mesenchyme—answering how dorsoventral pigmentation boundaries are set—by demonstrating that Tbx15 loss permits ectopic Agouti expression dorsally.

    Evidence Targeted Tbx15 KO mice with skin transplantation and fate-mapping in vivo

    PMID:14737183

    Open questions at the time
    • Direct transcriptional target linking Tbx15 to Agouti repression not identified
    • Mechanism of positional instruction to dermal cells unknown
  2. 2005 High

    Defining Tbx15 as a skeletal developmental regulator by showing that its loss reduces proliferation of chondrocytes and mesenchymal precursors, and that it acts synergistically with Gli3 and Alx4 to pattern the scapula.

    Evidence Tbx15 null mice with BrdU/Ki67 proliferation assays; double and triple mutant analysis (Tbx15/Gli3/Alx4/Cart1)

    PMID:15652702 PMID:15728667

    Open questions at the time
    • Direct transcriptional targets mediating proliferation control in chondrocytes not identified
    • Whether Tbx15 and Gli3 converge on shared promoters or act in parallel pathways is unresolved
  3. 2007 High

    Revealing the core molecular mechanism of TBX15: homo/heterodimerization, T half-site DNA binding, and Groucho-dependent transcriptional repression, establishing it as both a repressor and context-dependent activator.

    Evidence In vitro DNA binding assays, co-immunoprecipitation for dimerization, luciferase reporter assays for repression, Groucho interaction assays

    PMID:17584735

    Open questions at the time
    • Endogenous genomic targets bound in vivo not mapped at this stage
    • Conditions under which TBX15 switches from repression to activation not defined
  4. 2008 High

    Linking TBX15 insufficiency to human Cousin syndrome by demonstrating that patient mutations produce truncated proteins subject to accelerated degradation despite retaining DNA-binding capacity.

    Evidence Patient genomic sequencing, in vitro DNA binding with mutant proteins, western blot for protein stability

    PMID:19068278

    Open questions at the time
    • Degradation pathway (proteasomal vs. other) not characterized
    • Whether partial protein activity contributes to phenotypic variability is unknown
  5. 2010 Medium

    Demonstrating that TBX15 and TBX6 compete for shared downstream transcriptional targets in paraxial mesoderm, explaining how ectopic Tbx6 phenocopies Tbx15 loss in skeletal patterning.

    Evidence Transgenic ectopic Tbx6 mice with skeletal phenotyping; in vitro luciferase competition assays

    PMID:20832395

    Open questions at the time
    • Identity of shared target genes beyond reporter constructs not determined
    • Whether competition occurs at endogenous chromatin in vivo is untested
  6. 2011 High

    Establishing TBX15 as a metabolic regulator in adipocytes: overexpression impairs differentiation, shifts lipid metabolism toward lipolysis, and reduces mitochondrial mass and respiratory capacity.

    Evidence Tbx15 overexpression in 3T3-L1 preadipocytes with Oil Red O, lipogenesis/lipolysis assays, Seahorse respirometry

    PMID:21282637

    Open questions at the time
    • Direct transcriptional targets mediating mitochondrial and metabolic effects not identified at this stage
    • Loss-of-function counterpart in adipocytes not yet tested
  7. 2012 Medium

    Demonstrating depot-specific requirement: Tbx15 knockdown impairs adipogenic and thermogenic gene programs in brown/brite but not epididymal white adipocytes, revealing cell-type-selective function.

    Evidence siRNA knockdown in primary adipocyte cultures from brown, inguinal white, and epididymal white depots with qPCR

    PMID:22912368

    Open questions at the time
    • Mechanism of depot selectivity not elucidated
    • Single knockdown approach without rescue experiment
  8. 2015 High

    Resolving TBX15's role in muscle fiber-type specification: Tbx15 ablation in vivo decreases glycolytic fibers, activates AMPK, and reduces Igf2, establishing it as a transcriptional determinant of glycolytic identity.

    Evidence Tbx15 KO mice with fiber-type immunostaining, muscle physiology, O₂ consumption, AMPK pathway and Igf2 expression analysis

    PMID:26299309

    Open questions at the time
    • Whether Igf2 is a direct transcriptional target of TBX15 or an indirect consequence of AMPK activation is unresolved
    • Upstream signals specifying Tbx15 expression in glycolytic fibers unknown
  9. 2016 Medium

    Identifying upstream regulation of TBX15 itself: NF-κB p65 directly binds two sites in the TBX15 promoter to upregulate its expression, placing TBX15 downstream of inflammatory signaling.

    Evidence ChIP for NF-κBp65 at TBX15 promoter, luciferase reporter assays with binding-site mutations, TNF-α stimulation

    PMID:27327083

    Open questions at the time
    • Physiological contexts where NF-κB–TBX15 axis operates in vivo not defined
    • Whether this regulation is relevant in non-cancer cell types untested
  10. 2017 Medium

    Extending the glycolytic programming role to adipocytes: within a single white fat depot, high-TBX15 cells are more glycolytic and low-TBX15 cells more oxidative, mirroring the muscle fiber-type paradigm.

    Evidence Flow cytometry sorting of adipocytes by Tbx15 expression level, Seahorse metabolic profiling, overexpression in cultured adipocytes

    PMID:28847884

    Open questions at the time
    • Causal versus correlative relationship in sorted endogenous cells not fully resolved
    • Downstream metabolic targets in adipocytes not identified
  11. 2019 High

    Identifying a direct transcriptional target for the browning function: TBX15 binds the Prdm16 promoter by ChIP, and adipose-specific Tbx15 KO mice fail to brown inguinal fat upon cold or β3-adrenergic stimulation.

    Evidence Adipose-specific Tbx15 KO (adiponectin-Cre), ChIP at Prdm16 promoter, cold exposure and CL316243 treatment with thermogenic gene expression

    PMID:31352005

    Open questions at the time
    • Whether TBX15 directly activates or derepresses Prdm16 transcription not distinguished
    • Genome-wide binding profile in adipocytes not yet available at this stage
  12. 2021 Medium

    Positioning TBX15 as a master trans-regulatory hub in human preadipocytes controlling ~130 adipose co-expression network genes including PPARG and KLF15, linking it to abdominal obesity genetics.

    Evidence siRNA knockdown in human primary preadipocytes with RNA-seq; integration with TWAS and co-expression network analysis

    PMID:34340684

    Open questions at the time
    • Which of the 130 genes are direct versus indirect targets not distinguished
    • Functional validation of individual network genes downstream of TBX15 lacking
  13. 2022 Medium

    Identifying ADAMTS2 as a direct transcriptional activation target of TBX15 in palatal mesenchyme, extending TBX15's direct target repertoire to craniofacial development.

    Evidence ChIP assay and co-transfection luciferase reporter for TBX15 binding/activating ADAMTS2 promoter; immunofluorescence co-localization in E13.5 embryos

    PMID:36124393

    Open questions at the time
    • Functional consequence of ADAMTS2 activation for palate morphogenesis not tested
    • Whether other T-box factors compete at this promoter unknown

Open questions

Synthesis pass · forward-looking unresolved questions
  • Key unresolved questions include the genome-wide direct target repertoire of TBX15 across tissues, the structural basis for its switch between repression and activation, and how its metabolic programming roles in muscle and adipose are coordinated in whole-body energy homeostasis.
  • No crystal structure of TBX15 or TBX15–Groucho complex
  • Genome-wide ChIP-seq in primary muscle tissue not performed
  • In vivo relevance of TBX15-mediated immune gene regulation in adipose (from preprint) not confirmed in peer-reviewed study

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0140110 transcription regulator activity 8 GO:0003677 DNA binding 4
Localization
GO:0005634 nucleus 2
Pathway
R-HSA-1266738 Developmental Biology 4 R-HSA-74160 Gene expression (Transcription) 4 R-HSA-1430728 Metabolism 3
Partners
GLI3PRDM16TBX18TLE1

Evidence

Reading pass · 19 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2005 Tbx15 is required for skeletal development; loss-of-function in mice causes reduced proliferation of prehypertrophic chondrocytes and mesenchymal precursor cells, demonstrating Tbx15 controls cell number in skeletal templates. Tbx15 null mutant mouse analysis with proliferation assays (BrdU/Ki67), histology, and skeletal staining Mechanisms of development High 15652702
2004 Tbx15 expressed in dorsal mesenchyme provides an instructional cue for positional identity of dorsal dermis; loss of Tbx15 causes dorsal expansion of Agouti expression, demonstrating Tbx15 is required upstream of Agouti to establish the dorsoventral pigmentation boundary. Targeted Tbx15 knockout mice, skin transplantation experiments, fate-mapping, in situ hybridization for Agouti PLoS biology High 14737183
2007 TBX15 (and TBX18) homo- and heterodimerize, bind various combinations of T half-sites on DNA, repress transcription in a Groucho corepressor-dependent manner, and contain functional domains for nuclear localization, DNA binding, and transcriptional modulation. In vitro DNA binding assays, co-immunoprecipitation for dimerization, luciferase reporter assays for transcriptional repression, Groucho interaction assays The Journal of biological chemistry High 17584735
2015 Tbx15 is specifically expressed in glycolytic myofibers; ablation in vivo decreases glycolytic fiber number (with compensatory increase in oxidative fibers), activates AMPK signaling, and decreases Igf2 expression, placing Tbx15 as a transcriptional regulator of glycolytic fiber identity and muscle metabolism. Tbx15 knockout mice, fiber-type immunostaining, muscle contraction/relaxation assays, oxygen consumption measurements, AMPK pathway analysis, Igf2 qPCR Nature communications High 26299309
2011 Overexpression of Tbx15 in 3T3-L1 preadipocytes impairs adipocyte differentiation, decreases triglyceride content, reduces basal lipogenic rate, increases basal lipolytic rate, reduces mitochondrial mass by 15%, reduces basal mitochondrial respiration by 28%, and reduces mitochondrial respiratory capacity by 45%. Tbx15 overexpression in 3T3-L1 cells, Oil Red O staining, lipogenesis/lipolysis assays, mitochondrial mass measurement, Seahorse respirometry Proceedings of the National Academy of Sciences of the United States of America High 21282637
2012 Tbx15 knockdown (>90%) in primary brown and inguinal white (brite) adipocyte cultures reduces expression of adipogenesis markers (PPARγ, aP2) and brown phenotypic markers (PRDM16, PGC-1α, UCP1), but has no effect on epididymal white adipocytes, demonstrating Tbx15 is required for the adipogenic and thermogenic programs specifically in brown/brite-competent adipocytes. siRNA knockdown in primary adipocyte cultures from different depots, qPCR for adipogenic and thermogenic markers American journal of physiology. Endocrinology and metabolism Medium 22912368
2008 Human TBX15 mutations causing Cousin syndrome produce truncated proteins that, despite having an intact T-box capable of binding target DNA in vitro, are directed to early degradation, reducing cellular protein levels and causing TBX15 insufficiency. Patient genomic sequencing, in vitro DNA binding assays with mutant proteins, western blot for protein stability/degradation American journal of human genetics High 19068278
2019 TBX15 binds directly to a key region in the Prdm16 promoter (as determined by ChIP), regulating transcription of Prdm16 (master gene for adipocyte thermogenesis); adipose-specific Tbx15 knockout mice show impaired adipocyte browning in inguinal adipose tissue upon cold exposure or β3 adrenergic agonist treatment. Adipose-specific Tbx15 knockout (adiponectin-Cre), ChIP assay for TBX15 binding to Prdm16 promoter, cold exposure and CL316243 treatment, thermogenic gene expression analysis Molecular metabolism High 31352005
2017 Tbx15 overexpression in cultured adipocytes is sufficient to reduce oxidative and increase glycolytic metabolism; within a single white adipose depot, high Tbx15-expressing cells are more glycolytic while low Tbx15-expressing cells are more oxidative. Flow cytometry-based cell sorting by Tbx15 expression level, metabolic profiling (Seahorse), Tbx15 overexpression in cultured adipocytes Diabetes Medium 28847884
2021 TBX15 knockdown in human primary preadipocytes alters expression of 130 network genes in trans, including PPARG and KLF15, identifying TBX15 as a master trans-regulator of an adipose co-expression network controlling abdominal obesity-related genes. siRNA knockdown of TBX15 in human primary preadipocytes followed by RNA-seq; co-expression network and TWAS analyses Genome medicine Medium 34340684
2010 Ectopic expression of Tbx6 in segmented paraxial mesoderm produces Tbx15 null-like phenotypes in vertebral column, ribs, and appendicular skeleton; in vitro luciferase assays show Tbx6 competes with Tbx15 at shared target gene binding sites, demonstrating Tbx6 and Tbx15 compete for shared downstream transcriptional targets. Transgenic mouse system with ectopic Tbx6, skeletal phenotype analysis, in vitro luciferase transcriptional competition assays Developmental biology Medium 20832395
2005 Tbx15 and Gli3 have synergistic functions in formation of the scapular blade; genetic epistasis in double and triple mutants (Tbx15/Gli3/Alx4/Cart1) reveals Tbx15 acts together with these factors in patterning the shoulder girdle with region-specific roles. Double and triple mutant mouse analysis (Tbx15, Gli3, Alx4, Cart1), skeletal staining, marker gene expression analysis Development (Cambridge, England) Medium 15728667
2022 TBX15 binds to the promoter regions of the ADAMTS2 gene and activates its promoter activity, as shown by cellular co-transfection and ChIP assays; TBX15 and ADAMTS2 co-localize in posterior palatal mesenchymal cells during soft palate development. ChIP assay, co-transfection luciferase reporter assay, immunofluorescence co-localization in E13.5 mouse embryos Human mutation Medium 36124393
2021 TBX15 induces miR-152 expression, which targets KIF2C; KIF2C directly binds PKM2 and prevents its ubiquitination, increasing PKM2 stability and promoting glycolysis and autophagy; TBX15 overexpression suppresses this pathway to reduce doxorubicin resistance in breast cancer cells. Co-immunoprecipitation (KIF2C-PKM2 binding), luciferase reporter assay (miR-152/KIF2C), western blot for PKM2 ubiquitination, ECAR/OCR assays, in vivo xenograft models Cancer cell international Medium 34663310
2016 NF-κB signaling upregulates TBX15 expression in cancer cells via two functional NF-κB binding sites at positions -3302 and -3059 of the TBX15 gene, as demonstrated by luciferase reporter assays and ChIP showing direct NF-κBp65 binding. Luciferase reporter assays with NF-κB site mutations, ChIP for NF-κBp65 at TBX15 promoter, TNF-α and PMA/ionomycin stimulation PloS one Medium 27327083
2015 TBX15 overexpression in thyroid cancer cells reduces apoptosis, increases Bcl2 and Bcl-XL expression, and decreases Bax; conversely, siRNA knockdown of endogenous TBX15 increases apoptosis, demonstrating an antiapoptotic function for TBX15. Transfection of TBX15 in thyroid cancer cells, siRNA knockdown, apoptosis assays (Annexin V/PI), western blot for Bax/Bcl2/Bcl-XL Apoptosis Medium 26216026
2024 TBX15 directly regulates a network of immune response genes (B- and T-cell receptor signaling, JAK-STAT signaling, haematopoietic cell lineage pathways) in adipose tissue, as identified by combining RNA-seq from Tbx15 knockout mice with TBX15 ChIP-seq from 3T3-L1 cells overexpressing TBX15. RNA-seq of adipose tissue from Tbx15 KO mice, ChIP-seq of TBX15 in 3T3-L1 cells, integration to identify direct targets bioRxivpreprint Medium bio_10.1101_2024.09.20.614167
2026 A loss-of-function TBX15 variant (c.C1231T, p.Gln411Ter) produces a truncated protein with aberrant cytoplasmic mis-localization and significantly reduced transcriptional activity; Tbx15 is highly expressed in a specific palatal mesenchymal cell population during palatogenesis and co-localizes with osteogenic markers, implicating it in intramembranous bone formation. Protein subcellular localization assay, transcriptional activity reporter assay, single-nucleus RNA-seq of mouse palate, immunofluorescence co-localization International dental journal Medium 41904889
2011 PDX1 transcription factor represses the TBX15 promoter in a methylation-dependent manner; a differentially methylated region in the distal TBX15 promoter is hypomethylated in vascular IUGR placentas, correlating with decreased TBX15 expression. Bisulfite sequencing, promoter reporter/repression assay with PDX1, correlation of methylation with newborn measurements Epigenetics Low 20962579

Source papers

Stage 0 corpus · 34 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2005 The T-box transcription factor Tbx15 is required for skeletal development. Mechanisms of development 95 15652702
2017 Archaic Adaptive Introgression in TBX15/WARS2. Molecular biology and evolution 92 28007980
2004 Dorsoventral patterning of the mouse coat by Tbx15. PLoS biology 85 14737183
2007 Transcriptional repression by the T-box proteins Tbx18 and Tbx15 depends on Groucho corepressors. The Journal of biological chemistry 82 17584735
2015 Tbx15 controls skeletal muscle fibre-type determination and muscle metabolism. Nature communications 75 26299309
2012 An essential role for Tbx15 in the differentiation of brown and "brite" but not white adipocytes. American journal of physiology. Endocrinology and metabolism 74 22912368
2011 Mesodermal developmental gene Tbx15 impairs adipocyte differentiation and mitochondrial respiration. Proceedings of the National Academy of Sciences of the United States of America 68 21282637
2005 Genetics of shoulder girdle formation: roles of Tbx15 and aristaless-like genes. Development (Cambridge, England) 58 15728667
2008 TBX15 mutations cause craniofacial dysmorphism, hypoplasia of scapula and pelvis, and short stature in Cousin syndrome. American journal of human genetics 52 19068278
2002 Cloning of zebrafish T-box genes tbx15 and tbx18 and their expression during embryonic development. Mechanisms of development 46 12175500
2021 TBX15/miR-152/KIF2C pathway regulates breast cancer doxorubicin resistance via promoting PKM2 ubiquitination. Cancer cell international 44 34663310
1998 Cloning, mapping, and expression analysis of TBX15, a new member of the T-Box gene family. Genomics 40 9693034
2017 Tbx15 Defines a Glycolytic Subpopulation and White Adipocyte Heterogeneity. Diabetes 38 28847884
2021 CircPVT1 promotes progression in clear cell renal cell carcinoma by sponging miR-145-5p and regulating TBX15 expression. Cancer science 34 33453148
2021 Identification of TBX15 as an adipose master trans regulator of abdominal obesity genes. Genome medicine 33 34340684
2019 Tbx15 is required for adipocyte browning induced by adrenergic signaling pathway. Molecular metabolism 27 31352005
2011 Combination of promoter hypomethylation and PDX1 overexpression leads to TBX15 decrease in vascular IUGR placentas. Epigenetics 23 20962579
2019 MiR-212-5p inhibits the malignant behavior of clear cell renal cell carcinoma cells by targeting TBX15. European review for medical and pharmacological sciences 19 31858538
2016 Promoter methylation and downregulated expression of the TBX15 gene in ovarian carcinoma. Oncology letters 19 27698863
2016 NF-κB Mediates the Expression of TBX15 in Cancer Cells. PloS one 17 27327083
2015 Novel antiapoptotic effect of TBX15: overexpression of TBX15 reduces apoptosis in cancer cells. Apoptosis : an international journal on programmed cell death 14 26216026
2010 Tbx18 and Tbx15 null-like phenotypes in mouse embryos expressing Tbx6 in somitic and lateral plate mesoderm. Developmental biology 14 20832395
2013 Homozygosity for a novel truncating mutation confirms TBX15 deficiency as the cause of Cousin syndrome. American journal of medical genetics. Part A 13 24039145
2020 Osteoporosis- and obesity-risk interrelationships: an epigenetic analysis of GWAS-derived SNPs at the developmental gene TBX15. Epigenetics 10 31975641
2021 The effects of Tbx15 and Pax1 on facial and other physical morphology in mice. FASEB bioAdvances 8 34938962
2023 The overexpression and clinical significance of TBX15 in human gliomas. Scientific reports 6 37328486
2021 Tbx15/18/22 shares a binding site with Tbx6-r.b to maintain expression of a muscle structural gene in ascidian late embryos. Developmental biology 6 34963554
2023 Sulforaphane Targets the TBX15/KIF2C Pathway to Repress Glycolysis and Cell Proliferation in Gastric Carcinoma Cells. Nutrition and cancer 5 37139873
2024 TBX15 facilitates malignant progression of glioma by transcriptional activation of TXDNC5. iScience 3 38327797
2024 An abdominal obesity missense variant in the adipocyte thermogenesis gene TBX15 is implicated in adaptation to cold in Finns. American journal of human genetics 2 39515300
2022 Mutations in the TBX15-ADAMTS2 pathway associate with a novel soft palate dysplasia. Human mutation 1 36124393
2021 TBX15 rs98422, DNM3 rs1011731, RAD51B rs8017304, and rs2588809 Gene Polymorphisms and Associations With Pituitary Adenoma. In vivo (Athens, Greece) 1 33622874
2026 A Novel Nonsense Variant in TBX15 Transcription Factor Suggests an Expanded Genetic Spectrum Of Submucous Cleft Palate. International dental journal 0 41904889
2025 Expanding the Clinical Spectrum of Cousin Syndrome: A Novel Biallelic Missense Variant in TBX15 Causing a Milder Phenotype. American journal of medical genetics. Part A 0 40693652