Maintenance of β-cell identity through the transcription co-factors TBL1X and TBL1XR1
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PROVIDER: PRJNA1150530 | ENA |
REPOSITORIES: ENA
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Project description:Maintenance of β-cell identity through the transcription co-factors TBL1X and TBL1XR1
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Project description:Loss of β-cell identity is a main mechanism of β-cell dysfunction in diabetes, controlled by transcription factors that induce β-cell identity gene expression and “disallowed” gene repression. How transcription factors facilitate simultaneous expression and repression is not fully understood, representing a serious knowledge gap in diabetes research. We identified the transcriptional co-factors transducin β-like 1 x-linked (TBL1X) and its homolog TBL1X-related (TBL1XR1) (short: TBL/R1) as crucial regulators of β-cell identity and function, as β-cell specific knockout in mice leads to progressive hypoinsulinemia and hyperglycemia. Single-cell RNA sequencing revealed loss of β-cells, the emergence of polyhormonal cells, and reduced β-cell maturity upon TBL/R1 knockout, indicating dedifferentiation. Interactome screens and chromatin immunoprecipitation showed TBL/R1 directly regulate insulin gene expression by forming a gene regulatory network with PAX6 and HDAC3, which was also evident in human models. Our study uncovers a new regulatory layer maintaining β-cell identity, crucial for diabetes development and progression.
2026-01-01 | GSE283723 | GEO
Project description:Diffuse large B-cell lymphomas (DLBCL) encompass a heterogeneous group of diseases derived from different stages of B-cell differentiation. The most clinically aggressive forms of DLBCL, C5/MCD, carry activating mutations in canonical B-cell signaling pathways, as well as early-occurring hits in the poorly-characterized gene TBL1XR1. Here, we investigated the role of TBL1XR1 mutations in the early steps of malignant transformation. We found that TBL1XR1 mutations disrupt germinal center development, and introduce a cell fate bias towards memory B (MB) cells. At the molecular level, TBL1XR1 mutations trigger a switch, by which the SMRT/HDAC3 co-repressor complex shuttles between the lineage-defining transcription factors BCL6 and BACH2. We further demonstrate that terminal differentiation of TBL1XR1 mutant MB is limited upon recall, and that these MB re-enter the germinal center reaction instead, suggesting a role for these cells as the cell-of-origin of C5/MCD DLBCL.
2020-07-02 | GSE139059 | GEO
Project description:Our spatiotemporal data confirmed activation of Tbl1xr1 in hepatocytes after 2/3 hepatectomy. TBL1XR1 is a transcriptional cofactor inducing ubiquitination and degradation of NCoR/SMRT co-repressors and NCoR is a negative regulator of hepatocyte proliferation acting through histone deacetylases (HDACs). We have examined the role of TBL1XR1 in liver regeneration through in vivo shRNA knockdown using adeno-associated viruses (shNC and shTbl1xr1) specifically targeting hepatocytes. The knockdown of Tbl1xr1 results in impair hepatocyte proliferation.To investigate the downstream targets of TBL1XR1 during liver regenration, we here perform the bulk RNA-seq for shNC and shTbl1xr1 at D2 after hepatectomy. Our data show demonstrated that Tbl1xr1 knockdown not only led to reduced cell cycle genes but also to impaired fatty acid β-oxidation as the most obviously affected liver function.
2024-02-05 | GSE254481 | GEO
Project description:Direct neuronal reprogramming by temporal identity factors
| PRJNA716964 | ENA
Project description:TBL1XR1 gene is associated with multiple developmental disorders presenting several neurological aspects. The relative protein is involved in regulation of important cellular pathways and master regulators of transcriptional output including nuclear receptor repressors, Wnt signaling, and MECP2 protein. However, TBL1XR1 mutations (including complete loss of its functions) have not been experimentally studied in neurological context, leaving a lack of knowledge in the mechanisms at the basis of the diseases. We show that Tbl1xr1 knock-out mice exhibit behavioral and neuronal abnormalities. Either the absence of TBL1XR1, or point mutations interfering with stability/regulation of NCOR complex induced decreased proliferation and increased differentiation in neural progenitors. We suggest that this developmental unbalance is due to the failure in the regulation of MAPK cascade. Together, our results broaden the molecular and functional aftermath of TBL1XR1 deficiency associated with human disorders.
2021-03-16 | GSE162750 | GEO
Project description:Histone acetylation and the acetyl-lysine reader Brd4 have recently been implicated in embryonic stem cell (ESC) proliferation and self-renewal. We found that na•ve pluripotent ESCs exhibit increased incorporation of glucose-derived carbons onto acetylated histones and elevations in H3K9ac and Brd4 recruitment at pluripotency gene promoters. Surprisingly, both H3K9 acetyltransferases, GCN5 and PCAF, and Brd4 recruitment were dispensable for proliferation, self-renewal and pluripotency of na•ve ESCs. Na•ve ESCs maintain gene expression by stabilizing Mediator at core pluripotency genes in a Brd4-independent manner. Brd4-independent proliferation could also be achieved in metastable ESCs by overexpression of pluripotency transcription factors. Under all conditions, self-renewal required the DNA methylcytosine oxidases Tet1 and Tet2. These data reveal that there is minimal dependence on Brd4 for self-renewal of na•ve ESCs. Instead, the relative levels of DNA methylation and transcription factor abundance determine the requirement for bromodomain recognition of histone acetylation to the maintenance of stem cell identity.
2018-04-09 | GSE88769 | GEO
Project description:Transcriptional maintenance of cortical somatostatin interneuron subtype identity during migration
| PRJNA977997 | ENA
Project description:Embryonic stem cells (ESCs) cells run a self-renewal gene expression program, requiring the expression of certain transcription factors accompanied by a particular chromosome organization to maintain a balance between pluripotency and the capacity for rapid differentiation. However, how transcriptional regulation is linked to chromosome organization in ESCs remains enigmatic. Here we show that Cohesin exhibits a functional role in maintaining ESC identity through association with the pluripotency transcriptional network. ChIP-seq analyses of the cohesin subunit Rad21 reveal an ESC specific cohesin binding pattern that is characterized by a CTCF independent colocalization of cohesin with pluripotency related transcription factors. Upon ESC differentiation, these binding sites disappear and instead new CTCF independent Rad21 binding sites emerge, which are enriched for binding sites of transcription factors implicated in early differentiation. Furthermore, knock-down of cohesin subunits causes expression changes that are reminiscent of the depletion of key pluripotency transcription factors, demonstrating the functional relevance of the cohesin - pluripotency transcriptional network association. Finally, we show that Nanog physically interacts with the cohesin interacting proteins Stag1 and Wapl, further substantiating this association. Based on these findings we propose that a dynamic placement of cohesin by pluripotency transcription factors contributes to a chromosome organization supporting the ESC expression program. This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
2011-05-19 | E-GEOD-24030 | biostudies-arrayexpress
Project description:Cortical interneuron diversity arises from the interplay of intrinsic developmental patterning and local extrinsic cues. While individual genetic programs underlying cardinal cell type identity are established in immature neurons prior to integration into cortical circuits, it remains unclear whether distinct interneuron subtype identities are pre-established, and if so, how their identity is maintained prior to circuit integration. Sox6 is a transcription factor with an established role in the maturation of interneurons derived from the medial ganglionic eminence and cell-type specification in other neuronal and non-neuronal cells. To determine a possible role in maintaining cortical somatostatin-expressing (Sst+) interneuron subtype identity, we conditionally removed Sox6 (Sox6-cKO) in migrating Sst+ interneurons and assessed the effects on their mature identity. In adolescent animals, five of eight molecular Sst+ subtypes were nearly absent in the cortex of Sox6-cKO mice. This reduced subtype diversity was not due to a decrease in the overall number of Sst+ interneurons and cells displayed electrophysiological maturity and expressed genes enriched within the broad class of Sst+ interneurons. Furthermore, we show that at embryonic day 18.5, prior to cortical integration, mature Sst+ cell subtype identity could already be inferred in both control and Sox6-cKO cortices, suggesting that the loss in subtype diversity observed in the mature cortex is due to a disrupted subtype maintenance. Importantly, Sox6 removal at postnatal day 7, after Sst+ interneurons have finished migrating and begun integration into the network, did not disrupt marker expression of Sst+ subtypes in the mature cortex. Therefore, Sox6 is necessary during this migratory phase for maintenance of Sst+ subtypes identity, indicating that subtype maintenance requires active transcriptional programs during migration.
2023-08-25 | GSE233791 | GEO