Project description:Transcription factors (TF) are indispensable for maintaining cell identity through regulating cell specific gene expression. Distinct cell identities derived from a common progenitor are frequently perpetuated by shared TFs; yet the mechanisms that facilitate their cell specific regulatory targets are poorly characterized. We report that the TF NKX2.2 is critical for the identity of pancreatic islet α cells by directly activating α cell genes and repressing alternate islet cell fate genes. When compared to the known role of NKX2.2 in islet β cells, we demonstrate that NKX2.2 regulates novel α cell target genes, facilitated in part by α cell specific DNA binding at gene promoters. Furthermore, we have identified the reprogramming factor KLF4 as having enriched expression in α cells, where it co-occupies NKX2.2-bound α cell promoters and is necessary for NKX2.2 binding in α cells to co-regulate many NKX2.2 α cell transcriptional targets. Misexpression of Klf4 in β cells is sufficient to manipulate chromatin accessibility, increase binding of NKX2.2 at α cell specific promoters sites, and alter expression of NKX2.2-regulated cell specific targets. This study identifies KLF4 is a novel α cell identity factor that cooperates with NKX2.2 to regulate α cell identity.
Project description:Transcription factors (TF) are indispensable for maintaining cell identity through regulating cell specific gene expression. Distinct cell identities derived from a common progenitor are frequently perpetuated by shared TFs; yet the mechanisms that facilitate their cell specific regulatory targets are poorly characterized. We report that the TF NKX2.2 is critical for the identity of pancreatic islet α cells by directly activating α cell genes and repressing alternate islet cell fate genes. When compared to the known role of NKX2.2 in islet β cells, we demonstrate that NKX2.2 regulates novel α cell target genes, facilitated in part by α cell specific DNA binding at gene promoters. Furthermore, we have identified the reprogramming factor KLF4 as having enriched expression in α cells, where it co-occupies NKX2.2-bound α cell promoters and is necessary for NKX2.2 binding in α cells to co-regulate many NKX2.2 α cell transcriptional targets. Misexpression of Klf4 in β cells is sufficient to manipulate chromatin accessibility, increase binding of NKX2.2 at α cell specific promoters sites, and alter expression of NKX2.2-regulated cell specific targets. This study identifies KLF4 is a novel α cell identity factor that cooperates with NKX2.2 to regulate α cell identity.
Project description:Transcription factors (TF) are indispensable for maintaining cell identity through regulating cell specific gene expression. Distinct cell identities derived from a common progenitor are frequently perpetuated by shared TFs; yet the mechanisms that facilitate their cell specific regulatory targets are poorly characterized. We report that the TF NKX2.2 is critical for the identity of pancreatic islet α cells by directly activating α cell genes and repressing alternate islet cell fate genes. When compared to the known role of NKX2.2 in islet β cells, we demonstrate that NKX2.2 regulates novel α cell target genes, facilitated in part by α cell specific DNA binding at gene promoters. Furthermore, we have identified the reprogramming factor KLF4 as having enriched expression in α cells, where it co-occupies NKX2.2-bound α cell promoters and is necessary for NKX2.2 binding in α cells to co-regulate many NKX2.2 α cell transcriptional targets. Misexpression of Klf4 in β cells is sufficient to manipulate chromatin accessibility, increase binding of NKX2.2 at α cell specific promoters sites, and alter expression of NKX2.2-regulated cell specific targets. This study identifies KLF4 is a novel α cell identity factor that cooperates with NKX2.2 to regulate α cell identity.
Project description:Aim: Transcriptional analysis of E15.5 whole pancreas of Nkx2.2-LacZ/LacZ embryos versus control and Ngn3-Cre; Nkx2.2-flox/flox embryos versus control Methods: Embryonic pancreata were isolated at E15.5 from Nkx2.2 mutant mice and controls. Total RNA was extracted. Libraries were prepared from total RNA (RIN>8) with the TruSeq RNA prep kit (Illumina) and sequenced using the HiSeq2000 (Illumina) instrument. More than 20 million reads were mapped to the mouse genome (UCSC/mm9) using Tophat (version 2.0.4) with 4 mismatches and 10 maximum multiple hits. Significantly differentially expressed genes were calculated using DEseq. Results: There is significant overlap between the differentially expressed genes of whole body Nkx2.2 mutant embryos and endocrine progenitor specific Nkx2.2 mutant embryos; many of the downregulated genes (p-value < 0.05) are genes involved in beta cell function. Conclusion: Nkx2.2 functions within the endocrine progenitor lineage to activate beta cell genes
Project description:Transcription factors (TF) are indispensable for maintaining cell identity through regulating cell specific gene expression. Distinct cell identities derived from a common progenitor are frequently perpetuated by shared TFs; yet the mechanisms that facilitate their cell specific regulatory targets are poorly characterized. We report that the TF NKX2.2 is critical for the identity of pancreatic islet α cells by directly activating α cell genes and repressing alternate islet cell fate genes. When compared to the known role of NKX2.2 in islet β cells, we demonstrate that NKX2.2 regulates novel α cell target genes, facilitated in part by α cell specific DNA binding at gene promoters. Furthermore, we have identified the reprogramming factor KLF4 as having enriched expression in α cells, where it co-occupies NKX2.2-bound α cell promoters and is necessary for NKX2.2 binding in α cells to co-regulate many NKX2.2 α cell transcriptional targets. Misexpression of Klf4 in β cells is sufficient to manipulate chromatin accessibility, increase binding of NKX2.2 at α cell specific promoters sites, and alter expression of NKX2.2-regulated cell specific targets. This study identifies KLF4 is a novel α cell identity factor that cooperates with NKX2.2 to regulate α cell identity.
Project description:Transcription factors (TF) are indispensable for maintaining cell identity through regulating cell specific gene expression. Distinct cell identities derived from a common progenitor are frequently perpetuated by shared TFs; yet the mechanisms that facilitate their cell specific regulatory targets are poorly characterized. We report that the TF NKX2.2 is critical for the identity of pancreatic islet α cells by directly activating α cell genes and repressing alternate islet cell fate genes. When compared to the known role of NKX2.2 in islet β cells, we demonstrate that NKX2.2 regulates novel α cell target genes, facilitated in part by α cell specific DNA binding at gene promoters. Furthermore, we have identified the reprogramming factor KLF4 as having enriched expression in α cells, where it co-occupies NKX2.2-bound α cell promoters and is necessary for NKX2.2 binding in α cells to co-regulate many NKX2.2 α cell transcriptional targets. Misexpression of Klf4 in β cells is sufficient to manipulate chromatin accessibility, increase binding of NKX2.2 at α cell specific promoters sites, and alter expression of NKX2.2-regulated cell specific targets. This study identifies KLF4 is a novel α cell identity factor that cooperates with NKX2.2 to regulate α cell identity.
Project description:Transcription factors (TF) are indispensable for maintaining cell identity through regulating cell specific gene expression. Distinct cell identities derived from a common progenitor are frequently perpetuated by shared TFs; yet the mechanisms that facilitate their cell specific regulatory targets are poorly characterized. We report that the TF NKX2.2 is critical for the identity of pancreatic islet α cells by directly activating α cell genes and repressing alternate islet cell fate genes. When compared to the known role of NKX2.2 in islet β cells, we demonstrate that NKX2.2 regulates novel α cell target genes, facilitated in part by α cell specific DNA binding at gene promoters. Furthermore, we have identified the reprogramming factor KLF4 as having enriched expression in α cells, where it co-occupies NKX2.2-bound α cell promoters and is necessary for NKX2.2 binding in α cells to co-regulate many NKX2.2 α cell transcriptional targets. Misexpression of Klf4 in β cells is sufficient to manipulate chromatin accessibility, increase binding of NKX2.2 at α cell specific promoters sites, and alter expression of NKX2.2-regulated cell specific targets. This study identifies KLF4 is a novel α cell identity factor that cooperates with NKX2.2 to regulate α cell identity.
Project description:Transcription factors (TF) are indispensable for maintaining cell identity through regulating cell specific gene expression. Distinct cell identities derived from a common progenitor are frequently perpetuated by shared TFs; yet the mechanisms that facilitate their cell specific regulatory targets are poorly characterized. We report that the TF NKX2.2 is critical for the identity of pancreatic islet α cells by directly activating α cell genes and repressing alternate islet cell fate genes. When compared to the known role of NKX2.2 in islet β cells, we demonstrate that NKX2.2 regulates novel α cell target genes, facilitated in part by α cell specific DNA binding at gene promoters. Furthermore, we have identified the reprogramming factor KLF4 as having enriched expression in α cells, where it co-occupies NKX2.2-bound α cell promoters and is necessary for NKX2.2 binding in α cells to co-regulate many NKX2.2 α cell transcriptional targets. Misexpression of Klf4 in β cells is sufficient to manipulate chromatin accessibility, increase binding of NKX2.2 at α cell specific promoters sites, and alter expression of NKX2.2-regulated cell specific targets. This study identifies KLF4 is a novel α cell identity factor that cooperates with NKX2.2 to regulate α cell identity.
Project description:Nkx2.2 is an intestine-enriched transcription factor required for regeneration in planarians. The goal of this study was to identify differentially expressed transcripts in uninjured nkx2.2(RNAi) planarians.
Project description:The Nkx2.2 transcription factor contributes to regulate the timing of myelination in the CNS. Still, information about the regulon of Nkx2.2 in oligodendrocytes (Ols) and their progenitor cells (OPCs) is restricted to a few genes. Therefore we aimed to identify the entire regulon of Nkx2.2. We performed transcript profiling of postnatal Nkx2.2-/- mice, investigated the expression of selected transcripts in Ol lineage cells after siRNA induced Nkx2.2 knock-down, and identified the genome-wide active Nkx2.2 binding sites in murine OPCs and Ols by use of ChIP-sequencing technique. Thereby we have found 521 genes with active Nkx2.2 binding sites within 10,000 bp of their gene loci that furthermore are differently expressed in absence or lower expression of Nkx2.2. Functionally, the target genes are associated with mitosis, migration stop, protein transport, lipid metabolism, mitochondrial biogenesis, formation of Ca2+ waves, and WNT signalling. Furthermore, motif discovery techniques and tests for overlaps between sequencing reads suggest that MYRF, OLIG2, SOX10, and TCF3 interact or compete with Nkx2.2 in OPCs/Ols. However, the activator versus repressor activity of Nkx2.2 does not seem to depend on the potential interaction with either of the transcription factors. Test for overlaps with sites of specific histone 3 modifications show that the Nkx2.2 binding sites are more frequently associated H3K4me3 and H3K27ac in genes to which Nkx2.2 may act as an activator. This supports previous studies showing that Nkx2.2 acts in a HDAC1 dependent way. Together this provides new insight into how Nkx2.2 contributes to the timing of OPC differentiation and myelination in CNS.