ABSTRACT: Insm1 cooperates with Neurod1 and Foxa2 to maintain mature pancreatic β-cell function (Insm1, Neurod1 and Foxa2 ChipSeq data from pancreatic beta cell)
Project description:Genome-wide Insm1 binding sites analysis revealed an overrepresentation of sequences predicted to bind bHLH and/or forkhead factors, and further analyses demonstrated that most Insm1 sites in the genome are co-occupied by Neurod1 and Foxa2. Binding regions co-occupied by all three factors but not single Insm1 sites explained a significant fraction of gene expression changes in Insm1 mutant β-cells. Together, our data provide evidence that an Insm1, Neurod1 and Foxa2 network maintains a mature gene expression program in β-cells. 6 samples include, replicates of Insm1 and Foxa2, IgG pull down as a control
Project description:Genome-wide Insm1 binding sites analysis revealed an overrepresentation of sequences predicted to bind bHLH and/or forkhead factors, and further analyses demonstrated that most Insm1 sites in the genome are co-occupied by Neurod1 and Foxa2. Binding regions co-occupied by all three factors but not single Insm1 sites explained a significant fraction of gene expression changes in Insm1 mutant β-cells. Together, our data provide evidence that an Insm1, Neurod1 and Foxa2 network maintains a mature gene expression program in β-cells.
Project description:Insm1 cooperates with Neurod1 and Foxa2 to maintain mature pancreatic β-cell function (Expression data from islets of control and Insm1 conditional deleted adult pancreatic islets)
Project description:The zinc finger factor Insm1 is known to regulate differentiation of pancreatic β cells during development, Here we show that Insm1 is essential for the maintenance of functionally mature pancreatic β cells in mice. We used microarrays to analyse the global gene expression after deletion of insm1 in adult pancreatic β cells and identified functional important genes and immature islets releated genes deregulated in the mutatant islets.
Project description:NEUROD1 is a transcription factor that helps maintain a mature phenotype of pancreatic β cells. Disruption of Neurod1 during pancreatic development causes severe neonatal diabetes; however, the exact role of NEUROD1 in the differentiation programs of endocrine cells is unknown. Here, we report a crucial role of the NEUROD1 regulatory network in endocrine lineage commitment and differentiation. Mechanistically, transcriptome and chromatin landscape analyses demonstrate that Neurod1 inactivation triggers a downregulation of endocrine differentiation transcription factors and upregulation of non-endocrine genes within the Neurod1-deficient endocrine cell population, disturbing endocrine identity acquisition. Neurod1 deficiency altered the H3K27me3 histone modification pattern in promoter regions of differentially expressed genes, which resulted in gene regulatory network changes in the differentiation pathway of endocrine cells, compromising endocrine cell potential, differentiation, and functional properties.
Project description:This experiment used RNA-Seq technology to explore gene expression in mouse Insm1GFP.Cre/+ controls and Insm1 (Insm1GFP.Cre/GFP.Cre), Neurod1 (Insm1GFP.Cre/+; Neurod1LacZ/LacZ), or Pax6 (Insm1GFP.Cre/+; Pax6fl/fl) knockout FACS sorted pancreatic endocrine cells at E15.5. Comparison of Insm1GFP.Cre+/- and knockout animals revealed sets of differentially expressed genes that are required for endocrine cell specification and development.
Project description:This experiment used RNA-Seq technology to explore gene expression in mouse Insm1^GFP/Pdx1^CFP HIGH [het/het] FACS sorted pancreatic cells (pre-beta cells) and Insm1^GFP/Pdx1^CFP LOW [het/het] cells (other endocrine progenitors) at E15.5 and E18.5. Comparison of Insm1 +/Pdx HIGH and Insm1 +/Pdx LOW cells revealed a set of differentially expressed genes that are required for beta cell specification.
Project description:The zinc finger factor Insm1 is known to regulate differentiation of pancreatic ? cells during development, Here we show that Insm1 is essential for the maintenance of functionally mature pancreatic ? cells in mice. We used microarrays to analyse the global gene expression after deletion of insm1 in adult pancreatic ? cells and identified functional important genes and immature islets releated genes deregulated in the mutatant islets. We used 8 mutant and 8 litter matched control mice for the islets preparation.
Project description:We investigated genome-wide occupancy of CREB, CREB coactivators, lineage determining transcription factors and histone acetylation to uncover mechanisms behind tissue-specific gene induction by cAMP in pancreatic islets. CREB mediates effects of cAMP on cellular gene expression. Most core CREB target genes are ubiquitously induced following recruitment of CREB and its coactivators to promoter proximal binding sites. We found that CREB stimulates the expression of pancreatic beta cell genes by binding to sites within distal enhancers. By contrast with its transient effects on core target genes, CREB stimulates pancreatic beta cell specific gene expression in a sustained manner, reflecting increases in the CBP-mediated acetylation of resident nucleosomes that recruit the chromatin reader BRD4. CREB cooperates with the lineage specific activator Neurod1 in establishing cAMP-responsive enhancers in beta cells. As deletion of a CREB-Neurod1 bound enhancer within the Lrrc10b-Syt7 super-enhancer locus disrupted the expression of both genes and decreased glucose-induced insulin secretion, our results demonstrate how cooperativity between signal dependent and lineage determining factors promotes the expression of cell type-specific gene programs in response to extracellular cues.
Project description:We investigated genome-wide occupancy of CREB, CREB coactivators, lineage determining transcription factors and histone acetylation to uncover mechanisms behind tissue-specific gene induction by cAMP in pancreatic islets. CREB mediates effects of cAMP on cellular gene expression. Most core CREB target genes are ubiquitously induced following recruitment of CREB and its coactivators to promoter proximal binding sites. We found that CREB stimulates the expression of pancreatic beta cell genes by binding to sites within distal enhancers. By contrast with its transient effects on core target genes, CREB stimulates pancreatic beta cell specific gene expression in a sustained manner, reflecting increases in the CBP-mediated acetylation of resident nucleosomes that recruit the chromatin reader BRD4. CREB cooperates with the lineage specific activator Neurod1 in establishing cAMP-responsive enhancers in beta cells. As deletion of a CREB-Neurod1 bound enhancer within the Lrrc10b-Syt7 super-enhancer locus disrupted the expression of both genes and decreased glucose-induced insulin secretion, our results demonstrate how cooperativity between signal dependent and lineage determining factors promotes the expression of cell type-specific gene programs in response to extracellular cues.
