Transcriptional coactivator MED15 is required for beta cell maturation
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA564631 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR10089200_1.fastq.gz | Fastqsanger.gz | |||
| SRR10089200_2.fastq.gz | Fastqsanger.gz | |||
| SRR10089201_1.fastq.gz | Fastqsanger.gz | |||
| SRR10089201_2.fastq.gz | Fastqsanger.gz | |||
| SRR10089202_1.fastq.gz | Fastqsanger.gz |
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Project description:Mediator, a co-regulator required for RNA pol II activity, interacts with tissue-specific transcription factors to regulate development and maintain homeostasis. We sought to understand whether Mediator subunit MED15 acts as a node that controls tissue-specific gene expression, using pancreatic insulin-producing β-cell maturation as a model. We found Med15 to be expressed during mouse pancreatic organogenesis and β-cell maturation; moreover, islets from human T2D donors feature reduced MED15 expression. Loss of Med15 in mouse β-cells caused defects in maturation without affecting β-cell mass or insulin expression. ChIP-seq and co-immunoprecipitation analyses determined that Med15 binds β-cell transcription factors Nkx6-1 and NeuroD1 to regulate key β-cell maturation genes. Human embryonic stem cell derived β-like cells, genetically engineered to express high levels of MED15, had increased maturation markers and improved insulin secretion. We provide the first evidence of the importance of Mediator in β-cell maturation and demonstrate an additional layer of control that tunes transcription factor function.
2024-09-10 | GSE137145 | GEO
Project description:Mediator, a co-regulator complex required for RNA Polymerase II activity, interacts with tissue-specific transcription factors to regulate development and maintain homeostasis. We observe reduced Mediator subunit MED15 expression in endocrine hormone-producing pancreatic islets isolated from people living with type 2 diabetes and sought to understand how MED15 and Mediator control gene expression programs important for the function of insulin-producing β-cells. Here we show that Med15 is expressed during mouse β-cell development and maturation. Knockout of Med15 in mouse β-cells causes defects in β-cell maturation without affecting β-cell mass or insulin expression. ChIP-seq and co-immunoprecipitation analyses found that Med15 binds β-cell transcription factors Nkx6-1 and NeuroD1 to regulate key β-cell maturation genes. In support of a conserved role during human development, human embryonic stem cell-derived β-like cells, genetically engineered to express high levels of MED15, express increased levels of maturation markers. We provide evidence of a conserved role for Mediator in β-cell maturation and demonstrate an additional layer of control that tunes β-cell transcription factor function.
| S-EPMC11461855 | biostudies-literature
Project description:Activation domains (ADs) within transcription factors (TFs) induce gene expression by recruiting coactivators to specific regulatory regions. Within the prevailing model, TF-coactivator recruitment is independent of DNA binding, which is consistent with direct AD-coactivator interactions seen outside cells. However, this independence was not yet tested within the genomic context. Here, we targeted two Med15-interacting ADs to hundreds of budding yeast promoters through fusions with multiple DNA binding domains (DBDs), gradually controlling their abundances using libraries of synthetic promoters. Genomic profiling revealed that AD identity influences DNA binding locations and that transcription induction and Med15 recruitment are restricted to a subset of DBD-bound promoters displaying flexible expression, multiple-TFs binding, and fuzzy nucleosome architecture. Further, when fused to a DBD, Med15 redirected binding towards promoters of fuzzy nucleosomes, overcoming DBD-based preferences. Our results demonstrate that ADs and their recruited coactivators posses an inherent preference for genomic localization and, therefore, define the subset of induced promoters.
2024-07-27 | GSE234432 | GEO
Project description:The multiprotein Mediator complex is an important regulator of RNA polymerase II-dependent genes in eukaryotic cell. In contrast to the situation in many other eukaryotes, the conserved Med15 protein is not a stable component of Mediator isolated from fission yeast. We now demonstrate that Med15 exists in a protein complex together with Hrp1, an ATP-dependent chromatin remodeling protein. The Med15/Hrp1 subcomplex is not a component of the core Mediator complex, but can interact with the repressive L-Mediator conformation. Deletion of MED15 and HRP1 cause similar effects on global steady-state levels of mRNA, but only MED15 is required for galactose-dependent activation of the inv1 gene. Hrp1 has been found in complex with other proteins and genome-wide analysis demonstrates that Med15 only associates with a distinct subset of Hrp1-bound gene promoters. Global analysis reveals that Hrp1-binding normally is associated with increased histone H3 density, but at promoters also bound by Med15, histone H3 density is instead increased. Our findings reveal that Med15 functions as a separate entity in fission yeast and indicate that the function and organization of the Mediator complex may differ significantly between eukaryotes. Keywords: ChIP-chip
2010-09-21 | GSE10079 | GEO
Project description:The Mediator is composed of multiple of proteins in the head, body, tail and CDK subunits conserved from yeast to humans. However, not all the components are required for transcription. Components of the tail subunit are not essential but to varying degrees are required for changes in transcription to stress. While some stresses are familiar such as heat, desiccation, and starvation, others are exotic yet elicit a physical stress response. MCHM is a hydrotrope that induces growth arrest in yeast. By exploiting genetic variation, specifically in Med15, between yeast strains, we found that Med15 with the polyQ expansion conferred MCHM sensitivity. This sensitivity was not from a loss of function as the reciprocal hemizygous hybrids were all sensitive, suggesting that there is an incompatibility between Mediator complexes from genetic divergent yeast strains. Transcriptomics from yeast expressing the incompatible Med15 changed expression in diverse pathways. Expansion of polyQ tracts in Med15 resulted in multiple isoforms which were mostly from likely post-translational modifications. Stability of Med15 was dependent on Ydj1, a chaperone and the incompatible Med15 allele was expressed at lower levels and less stable than the compatible Med15 allele. Med15 is tethered to the rest of the Mediator complex via Med2 and 3. Deletion of either Med2 or Med3 changes the Med15 isoform patterns in the in a similar manner whereas deletion of Med5, a distal component of the tail did not change the pattern. The med2 and 3 mutants are similarly sensitive to MCHM while med5 mutants are not. Differences between the Med15 alleles extend to responses to different stresses. Whereas the incompatible allele of Med15 improved growth to chemicals that produce free radicals, and the compatible allele of Med15 improved growth to reducing agents, caffeine, and hydroxyurea. This may reflect the positive and negative role that Med15 has in transcription.
2020-04-06 | GSE129898 | GEO
Project description:A hallmark of aging is chronic systemic inflammation, which is exacerbated by the hypersecretory aging phenotype known as the senescence-associated secretory phenotype (SASP). How the SASP is initiated to accelerate tissue inflammation and aging is an outstanding question in ageing biology. Here, we showed that phosphorylation of the mediator subunit MED15 at T603 is able to control the SASP and aging. Transforming growth factor-β (TGFβ) selectively induces CDK1-mediated MED15 T603 phosphorylation to control SASP gene expression. The MED15 T603 dephosphorylated mutant (T603A) inhibits the SASP and cell senescence, whereas the T603 phosphorylation-mimicking mutant (T603D) has the opposite effect. Mechanistically, forkhead box protein A1 (FOXA1) preferentially binds to unphosphorylated but not phosphorylated MED15 at T603 to suppress SASP gene expression. Notably, aging mice harboring dephosphorylated mutation in this phosphosite exhibit improved learning and memory through the attenuation of the SASP across tissues. Overall, our study indicates that MED15 T603 phosphorylation serves as a control switch for SASP production, which underlies tissue aging and cognitive decline and provides a novel target for age-related pathology.
2025-08-27 | GSE285138 | GEO
Project description:The weaning period consist of a critical postnatal window for structural and physiologic maturation of rat beta cells. To investigate transcriptome changes involved in the maturation of beta cells neighboring this period we performed microarray analysis in FACS beta cell enriched populations to detail the global programme of gene expression to identify its changes during this process. Male Wistar rats were selected at the initial point of a postnatal critical period (postnatal 20d) for pancreatic maturation for RNA extraction and hybridization on Affymetrix microarrays. We obtained immature and mature beta cell-enriched populations from postnatal 20d and 2 months animals in order to compare their expression profiles. To that end, we used primary cultured FACS-enriched beta cell populations according to their FSC, SSC and autoflourescence. We used three replicates for each condition.
2016-07-27 | E-GEOD-76969 | biostudies-arrayexpress
Project description:A hallmark of aging is chronic systemic inflammation, which is exacerbated by the hypersecretory aging phenotype known as the senescence-associated secretory phenotype (SASP). How the SASP is initiated to accelerate tissue inflammation and aging is an outstanding question in ageing biology. Here, we showed that phosphorylation of the mediator subunit MED15 at T603 is able to control the SASP and aging. Transforming growth factor-β (TGFβ) selectively induces CDK1-mediated MED15 T603 phosphorylation to control SASP gene expression. The MED15 T603 dephosphorylated mutant (T603A) inhibits the SASP and cell senescence, whereas the T603 phosphorylation-mimicking mutant (T603D) has the opposite effect. Mechanistically, forkhead box protein A1 (FOXA1) preferentially binds to unphosphorylated but not phosphorylated MED15 at T603 to suppress SASP gene expression. Notably, aging mice harboring dephosphorylated mutation in this phosphosite exhibit improved learning and memory through the attenuation of the SASP across tissues. Overall, our study indicates that MED15 T603 phosphorylation serves as a control switch for SASP production, which underlies tissue aging and cognitive decline and provides a novel target for age-related pathology.
2025-08-27 | GSE285137 | GEO
Project description:Activation domains (ADs) within transcription factors (TFs) induce gene expression by recruiting coactivators to specific regulatory regions. Within the prevailing model, TF-coactivator recruitment is independent of DNA binding, which is consistent with direct AD-coactivator interactions seen outside cells. However, this independence was not yet tested within the genomic context. Here, we targeted two Med15-interacting ADs to hundreds of budding yeast promoters through fusions with multiple DNA binding domains (DBDs), gradually controlling their abundances using libraries of synthetic promoters. Genomic profiling revealed that AD identity influences DNA binding locations and that transcription induction and Med15 recruitment are restricted to a subset of DBD-bound promoters displaying flexible expression, multiple-TFs binding, and fuzzy nucleosome architecture. Further, when fused to a DBD, Med15 redirected binding towards promoters of fuzzy nucleosomes, overcoming DBD-based preferences. Our results demonstrate that ADs and their recruited coactivators posses an inherent preference for genomic localization and, therefore, define the subset of induced promoters.
2023-12-19 | GSE234431 | GEO
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