Project description:The key transcription factors that control the embryonic stem cell gene expression program have been identified, but how they function to implement this program is not well understood. While screening for genes essential for maintenance of ES cell state, we identified many components of the Mediator and Cohesin complexes. Mediator and Cohesin were found to physically and functionally connect the enhancers and core promoters of active genes. An ES cell Mediator complex was found to copurify with Cohesin and its loading factor Nipbl, and normal levels of these proteins were essential for expression of the genes they occupy and for maintenance of ES cell state. See associated publication.
Project description:This SuperSeries is composed of the following subset Series: GSE27714: Enhancer Decommissioning by LSD1 During Embryonic Stem Cell Differentiation (expression) GSE27841: Enhancer Decommissioning by LSD1 During Embryonic Stem Cell Differentiation (ChIP-seq) Refer to individual Series
Project description:The master transcription factors Oct4, Sox2 and Nanog bind enhancer elements and recruit the Mediator co-activator to activate much of the gene expression program of embryonic stem cells (ESCs). We report here that the ESC master transcription factors and Mediator form M-bM-^@M-^\super-enhancersM-bM-^@M-^] at most genes known to control the pluripotent state, including those encoding the master transcription factors themselves. These super-enhancers consist of extraordinarily large genomic domains occupied by exceptional amounts of Oct4, Sox2, Nanog, Klf4, Esrrb and Mediator. Super-enhancers stimulate considerably higher transcription than typical enhancers in vivo and in reporter vectors. Reduced levels of Oct4 or Mediator cause preferential loss of expression of super-enhancer-associated genes relative to other genes, suggesting how changes in gene expression programs might be accomplished during development. In other more differentiated cells, super-enhancers containing cell-type-specific master transcription factors are also found at genes that define cell identity. These results implicate super-enhancers in the control of mammalian cell identity and differentiation. Time-course of gene expression following shRNA knockdown of Oct4 and Med12.
Project description:This SuperSeries is composed of the following subset Series: GSE22556: Control of Embryonic Stem Cell State by Mediator and Cohesin (Agilent gene expression data) GSE22562: Control of Embryonic Stem Cell State by Mediator and Cohesin (Illumina ChIP-Seq data) Refer to individual Series
Project description:Nucleosome remodeling results in loss of histone occupancy. To gain insight into variations in H3 occupancy in different murine cell types, chromatin immunoprecipitation coupled with massive parallel sequencing (ChIP-seq) was performed to determine genome wide occupancy of H3 in ES cells, myotubes and pro-B cells. DNA was enriched by chromatin immunoprecipitation (ChIP) and analyzed by Solexa sequencing. ChIP was performed using an antibody against total H3 in murine ES cells in normal culture conditions, murine ES cells treated with the TGF-beta inhibitor (SB431542, 10uM) for 24 hours, myotubes differentiated for 48 hours and pro-B cells under normal culture conditions.
Project description:Transcription factors and chromatin modifiers play important roles in programming and reprogramming of cellular states during development. Much is known about the role of these regulators in gene activation, but relatively little is known about the critical process of enhancer silencing during differentiation. Here we show that the H3K4/K9 histone demethylase LSD1 plays an essential role in decommissioning enhancers during differentiation of embryonic stem cells (ESCs). LSD1 occupies enhancers of active genes critical for control of ESC state. However, LSD1 is not essential for maintenance of ESC identity. Instead, ESCs lacking LSD1 activity fail to fully differentiate and ESC-specific enhancers fail to undergo the histone demethylation events associated with differentiation. At enhancers, LSD1 is a component of the NuRD complex, which contains additional subunits that are necessary for ESC differentiation. We propose that the LSD1-NuRD complex decommissions enhancers of the pluripotency program upon differentiation, which is essential for complete shutdown of the ESC gene expression program and the transition to new cell states. This represents the expression part of the study.
Project description:The master transcription factors Oct4, Sox2 and Nanog bind enhancer elements and recruit the Mediator co-activator to activate much of the gene expression program of embryonic stem cells (ESCs). We report here that the ESC master transcription factors and Mediator form “super-enhancers” at most genes known to control the pluripotent state, including those encoding the master transcription factors themselves. These super-enhancers consist of extraordinarily large genomic domains occupied by exceptional amounts of Oct4, Sox2, Nanog, Klf4, Esrrb and Mediator. Super-enhancers stimulate considerably higher transcription than typical enhancers in vivo and in reporter vectors. Reduced levels of Oct4 or Mediator cause preferential loss of expression of super-enhancer-associated genes relative to other genes, suggesting how changes in gene expression programs might be accomplished during development. In other more differentiated cells, super-enhancers containing cell-type-specific master transcription factors are also found at genes that define cell identity. These results implicate super-enhancers in the control of mammalian cell identity and differentiation. ChIP-Seq and controls associated with Super-Enhancers in murine cell types