Poised RNA Polymerase II changes over developmental time and prepares genes for future expression (ChIP-seq data)
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ABSTRACT: Poised RNA polymerase II is predominantly found at developmental control genes and is thought to allow their rapid and synchronous induction in response to extracellular signals. How the recruitment of poised RNA Pol II is regulated during development is not known. By isolating muscle tissue from Drosophila embryos at five stages of differentiation, we show that the recruitment of poised Pol II occurs at many genes de novo and this makes them permissive for future gene expression. When compared to other tissues, these changes are stage-specific and not tissue-specific. In contrast, Polycomb group repression is tissue-specific and in combination with Pol II (the balanced state) marks genes with highly dynamic expression. This suggests that poised Pol II is temporally regulated and is held in check in a tissue-specific fashion. We compare our data to mammalian embryonic stem cells and discuss a framework for predicting developmental programs based on chromatin state.
Project description:Poised RNA polymerase II is predominantly found at developmental control genes and is thought to allow their rapid and synchronous induction in response to extracellular signals. How the recruitment of poised RNA Pol II is regulated during development is not known. By isolating muscle tissue from Drosophila embryos at five stages of differentiation, we show that the recruitment of poised Pol II occurs at many genes de novo and this makes them permissive for future gene expression. When compared to other tissues, these changes are stage-specific and not tissue-specific. In contrast, Polycomb group repression is tissue-specific and in combination with Pol II (the balanced state) marks genes with highly dynamic expression. This suggests that poised Pol II is temporally regulated and is held in check in a tissue-specific fashion. We compare our data to mammalian embryonic stem cells and discuss a framework for predicting developmental programs based on chromatin state. MNase-seq data for examining nucleosome occupancy in specific Drosophila tissues during development
Project description:Poised RNA polymerase II is predominantly found at developmental control genes and is thought to allow their rapid and synchronous induction in response to extracellular signals. How the recruitment of poised RNA Pol II is regulated during development is not known. By isolating muscle tissue from Drosophila embryos at five stages of differentiation, we show that the recruitment of poised Pol II occurs at many genes de novo and this makes them permissive for future gene expression. When compared to other tissues, these changes are stage-specific and not tissue-specific. In contrast, Polycomb group repression is tissue-specific and in combination with Pol II (the balanced state) marks genes with highly dynamic expression. This suggests that poised Pol II is temporally regulated and is held in check in a tissue-specific fashion. We compare our data to mammalian embryonic stem cells and discuss a framework for predicting developmental programs based on chromatin state. mRNA-seq of Drosophila tissues during development
Project description:Poised RNA polymerase II is predominantly found at developmental control genes and is thought to allow their rapid and synchronous induction in response to extracellular signals. How the recruitment of poised RNA Pol II is regulated during development is not known. By isolating muscle tissue from Drosophila embryos at five stages of differentiation, we show that the recruitment of poised Pol II occurs at many genes de novo and this makes them permissive for future gene expression. When compared to other tissues, these changes are stage-specific and not tissue-specific. In contrast, Polycomb group repression is tissue-specific and in combination with Pol II (the balanced state) marks genes with highly dynamic expression. This suggests that poised Pol II is temporally regulated and is held in check in a tissue-specific fashion. We compare our data to mammalian embryonic stem cells and discuss a framework for predicting developmental programs based on chromatin state. ChIP-seq for Pol II, H3K4me3 and H3K27me3 in various Drosophila embryos and tissues
Project description:Poised RNA polymerase II is predominantly found at developmental control genes and is thought to allow their rapid and synchronous induction in response to extracellular signals. How the recruitment of poised RNA Pol II is regulated during development is not known. By isolating muscle tissue from Drosophila embryos at five stages of differentiation, we show that the recruitment of poised Pol II occurs at many genes de novo and this makes them permissive for future gene expression. When compared to other tissues, these changes are stage-specific and not tissue-specific. In contrast, Polycomb group repression is tissue-specific and in combination with Pol II (the balanced state) marks genes with highly dynamic expression. This suggests that poised Pol II is temporally regulated and is held in check in a tissue-specific fashion. We compare our data to mammalian embryonic stem cells and discuss a framework for predicting developmental programs based on chromatin state.
Project description:Poised RNA polymerase II is predominantly found at developmental control genes and is thought to allow their rapid and synchronous induction in response to extracellular signals. How the recruitment of poised RNA Pol II is regulated during development is not known. By isolating muscle tissue from Drosophila embryos at five stages of differentiation, we show that the recruitment of poised Pol II occurs at many genes de novo and this makes them permissive for future gene expression. When compared to other tissues, these changes are stage-specific and not tissue-specific. In contrast, Polycomb group repression is tissue-specific and in combination with Pol II (the balanced state) marks genes with highly dynamic expression. This suggests that poised Pol II is temporally regulated and is held in check in a tissue-specific fashion. We compare our data to mammalian embryonic stem cells and discuss a framework for predicting developmental programs based on chromatin state.
Project description:Enhancers play a central role in precisely regulating the spatiotemporal expression of developmentally regulated genes. The molecular mechanisms and factors required for controlling the inactive or poised enhancers and their function in future gene activation remain elusive. Here, we have identified that Ell3, a member of the Ell (Eleven-nineteen Lysine-rich Leukemia gene) family of RNA Pol II elongation factors, predominately occupies active and inactive enhancers of many developmentally regulated genes in mouse embryonic stem cells. Ell3 localizes to active enhancers of key stem cell renewal genes, but is not required for maintaining the undifferentiated state. Instead, Ell3 binding to inactive or poised enhancers is essential for marking them for stem cell specification through regulating the activation of key lineage-specific genes throughout differentiation. Ell3M-bM-^@M-^Ys association with enhancers is required for setting up proper Pol II occupancy at the proximal promoter regions of neighboring genes. This functional interaction between Ell3 and proximal promoter Pol II is dependent on cohesin. The depletion of cohesin subunits removes Ell3 from the enhancers and results in reduction in the levels of promoter proximally paused Pol II. Our study demonstrates that Ell3 is required for stem cell fate specification through regulating Pol II pausing on key developmental genes in the undifferentiated state and for their proper expression during differentiation. ChIP-seq of Ell3 in mES cells. ChIP-seq of Pol II in mES cells after Ell3 shRNA and non-targeting shRNA. RNA-seq of mES cells after Ell3 shRNA and non-targeting shRNA. RNA-seq of mouse embryoid bodies at day five after non-targeting shRNA.
Project description:Enhancers play a central role in precisely regulating the spatiotemporal expression of developmentally regulated genes. The molecular mechanisms and factors required for controlling the inactive or poised enhancers and their function in future gene activation remain elusive. Here, we have identified that Ell3, a member of the Ell (Eleven-nineteen Lysine-rich Leukemia gene) family of RNA Pol II elongation factors, predominately occupies active and inactive enhancers of many developmentally regulated genes in mouse embryonic stem cells. Ell3 localizes to active enhancers of key stem cell renewal genes, but is not required for maintaining the undifferentiated state. Instead, Ell3 binding to inactive or poised enhancers is essential for marking them for stem cell specification through regulating the activation of key lineage-specific genes throughout differentiation. Ell3’s association with enhancers is required for setting up proper Pol II occupancy at the proximal promoter regions of neighboring genes. This functional interaction between Ell3 and proximal promoter Pol II is dependent on cohesin. The depletion of cohesin subunits removes Ell3 from the enhancers and results in reduction in the levels of promoter proximally paused Pol II. Our study demonstrates that Ell3 is required for stem cell fate specification through regulating Pol II pausing on key developmental genes in the undifferentiated state and for their proper expression during differentiation.
Project description:Transcription of immediate early genes (IEGs) in neurons is exquisitely sensitive to neuronal activity, but the mechanism underlying the earliest of these transcription events is largely unknown. Here we demonstrate that very fast IEGs (VF-IEGs) such as arc/arg3.1 are poised for rapid transcription by the stalling of RNA Polymerase II (Pol II) just downstream of the transcription start site. RNAi-depletion of two subunits of a mediator of Pol II stalling, Negative Elongation Factor, reduces Pol II occupancy of the arc promoter and compromises rapid induction of arc and other VF-IEGs. In contrast, reduction of Pol II stalling did not prevent expression of other fast IEGs (F-IEGs). These F-IEGs are expressed with comparatively slower kinetics and largely lack promoter proximal Pol II stalling. Taken together, our data strongly indicate that very fast kinetics of neuronal IEG expression require poised Pol II and suggest a role for this mechanism in transcription-dependent learning and memory. TTX withdrawal induced neuronal activity. To study activity-induced gene expression, neurons were treated with TTX for 48 hours and then TTX was washed out either for 15 minutes (W15) or for 45 minutes (W45). Gene expression was measured in these two groups in comparison to TTX treated neurons.
Project description:Transcription of immediate early genes (IEGs) in neurons is exquisitely sensitive to neuronal activity, but the mechanism underlying the earliest of these transcription events is largely unknown. Here we demonstrate that very fast IEGs (VF-IEGs) such as arc/arg3.1 are poised for rapid transcription by the stalling of RNA Polymerase II (Pol II) just downstream of the transcription start site. RNAi-depletion of two subunits of a mediator of Pol II stalling, Negative Elongation Factor, reduces Pol II occupancy of the arc promoter and compromises rapid induction of arc and other VF-IEGs. In contrast, reduction of Pol II stalling did not prevent expression of other fast IEGs (F-IEGs). These F-IEGs are expressed with comparatively slower kinetics and largely lack promoter proximal Pol II stalling. Taken together, our data strongly indicate that very fast kinetics of neuronal IEG expression require poised Pol II and suggest a role for this mechanism in transcription-dependent learning and memory.