Genome-wide analysis of replication initiation in a TXR1 (Histone H3 K27 monomethyltranferase) overexpression strain in Tetrahymena
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PROVIDER: PRJNA865780 | ENA |
REPOSITORIES: ENA
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Project description:We mapped Tetrahymena macronuclear replication origins on a genome-wide scale using Okazaki fragments sequencing (OK-seq). OK-seq permits a high-resolution, quantitative analysis of replication fork initiation on a genome-wide scale that is dependent on the depth of coverage within a population of molecules. Replication initiation sites of the TXR1 (Histone H3 K27 monomethyltranferase) deletion strain were also studied compare to wild type using OK-seq.
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Project description:We mapped Tetrahymena macronuclear replication origins in TXR1 overexpression strain on a genome-wide scale using Okazaki fragments sequencing (OK-seq). Replication initiation sites of TXR1 overexpression strain followig cadmium induction of MMT1 promoter driven-TXR1 were studied compare to the uninduced TXR1 overexpression strain without cadmium using OK-seq.
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Project description:Genome-wide analysis of replication initiation in Tetrahymena
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Project description:Multipotential naïve CD4+ T cells differentiate into distinct lineages including Th1, Th2, Th17, and inducible T regulatory (iTreg) cells. The remarkable diversity of CD4+ T cells begs the question whether the observed changes reflect terminal differentiation with heritable epigenetic modifications or plasticity in T cell responses. We generated genome-wide histone H3 lysine 4 (H3K4) and lysine 27 (H3K27) trimethylation maps in naïve, Th1, Th2, Th17, iTreg, and natural (n)Treg cells. We find that while modifications of signature cytokine genes (Ifng, Il4, and Il17) partially conform to the expectation of lineage commitment, critical transcription factors such as Tbx21 exhibit a broad spectrum of epigenetic states, consistent with our demonstration of T-bet and IFN-γ induction in nTreg cells. Our data suggest an epigenetic mechanism underlying the specificity and plasticity of effector and regulatory T cells and also provide a framework for understanding complexity of CD4+ T helper cell differentiation. genome-wide analysis of histone H3 K4 and K27 trimethylation in different sub-lineages of mouse CD4+ T cells. (12 samples in total)
2009-01-21 | E-GEOD-14254 | biostudies-arrayexpress
Project description:Polycomb protein group (PcG)-dependent trimethylation on H3-K27(H3K27me3) regulates identity of embryonic stem cells (SCs). How H3K27me3 governs adult SCs and tissue development is unclear. Here, we conditionally target H3-K27-methyltransferases Ezh2 and Ezh1 to address their roles in mouse skin homeostasis. Postnatal phenotypes appear only in doubly-targeted skin, where H3K27me3 is abolished, revealing functional redundancy in EZH1/2 proteins. Surprisingly, while Ezh1/2-null hair follicles (HFs) arrest morphogenesis and degenerate due to defective proliferation and increased apoptosis, epidermis hyperproliferates and survives engraftment. mRNA-microarray studies reveal that despite these striking phenotypic differences, similar genes are upregulated in HF and epidermal Ezh1/2-null progenitors. Featured prominently are a) PcG-controlled non-skin lineage genes, whose expression is still significantly lower than in native tissues, and b) the PcG-regulated Ink4a/Inkb/Arf locus. Interestingly, even though Ink4a/Arf/Ink4b genes are fully activated in HF cells, they only partially so in epidermal-progenitors. Importantly, transduction of Ink4b/Ink4a/Arf shRNAs restores proliferation/survival of Ezh1/2-null HF progenitors in vitro, pointing towards the relevance of this locus to the observed HF phenotypes. Our findings reveal new insights into Polycomb-dependent tissue control and provide a new twist to how different progenitors within one tissue respond to loss of H3K27me3.
2011-06-09 | GSE26616 | GEO
Project description:Polycomb protein group (PcG)-dependent trimethylation on H3-K27(H3K27me3) regulates identity of embryonic stem cells (SCs). How H3K27me3 governs adult SCs and tissue development is unclear. Here, we conditionally target H3-K27-methyltransferases Ezh2 and Ezh1 to address their roles in mouse skin homeostasis. Postnatal phenotypes appear only in doubly-targeted skin, where H3K27me3 is abolished, revealing functional redundancy in EZH1/2 proteins. Surprisingly, while Ezh1/2-null hair follicles (HFs) arrest morphogenesis and degenerate due to defective proliferation and increased apoptosis, epidermis hyperproliferates and survives engraftment. mRNA-microarray studies reveal that despite these striking phenotypic differences, similar genes are upregulated in HF and epidermal Ezh1/2-null progenitors. Featured prominently are a) PcG-controlled non-skin lineage genes, whose expression is still significantly lower than in native tissues, and b) the PcG-regulated Ink4a/Inkb/Arf locus. Interestingly, even though Ink4a/Arf/Ink4b genes are fully activated in HF cells, they only partially so in epidermal-progenitors. Importantly, transduction of Ink4b/Ink4a/Arf shRNAs restores proliferation/survival of Ezh1/2-null HF progenitors in vitro, pointing towards the relevance of this locus to the observed HF phenotypes. Our findings reveal new insights into Polycomb-dependent tissue control and provide a new twist to how different progenitors within one tissue respond to loss of H3K27me3. RNAs from FACS-purified WT and Ezh1/2 2KO ORS, matrix and epidermal cells (Rendl et al., 2005) were provided to the Genomics Core Facility, MSKCC for quality control, quantification, reverse transcription, labeling and hybridization to MOE430A 2.0 microarray chips (Affymetrix). Arrays were scanned per the manufacturer’s specifications for the Affymetrix MOE430v2 chip. Images were background-subtracted. Probesets were identified as differentially expressed when the absolute fold change was ≥2. Probesets selected for visualization were log2 transformed and were analyzed with hierarchical clustering (Pearson correlation, average linkage), and visualized with heatmaps to assist in interpretation.
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Project description:Through epigenetic modifications and selective incorporation of histone variants into chromatin, eukaryotic cells can adjust their transcriptional profile in response to molecular needs. We used the nuclear dimorphic ciliate protozoan, Tetrahymena thermophila, as a model system to investigate the dynamics of H3 variant function. H3.3 is the ancestral H3 variant with key roles in regulating chromatin states and transcription. Functional proteomics and immunofluorescence analyses of H3.1 and H3.3 revealed a conserved role for Nrp1 and Asf1 histone chaperones in nuclear influx of histones. Cac2 and Hir1 have distinct localization patterns during different stages of the Tetrahymena life cycle and suggests that both Cac2 and Hir1 might be dispensable for the replication-dependent and -independent deposition of H3.1 and H3.3, respectively. ChIP-seq experiments in growing Tetrahymena show H3.3 enrichment over promoters, genes bodies, and transcription termination sites of highly transcribed genes. H3.3 knockout followed by RNA-seq reveals large-scale transcriptional alterations in functionally important genes. Our results provide an evolutionary perspective on H3.3’s conserved role in maintaining the transcriptional landscape of cells and on the emergence of specialized chromatin assembly pathways.
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Project description:Through epigenetic modifications and selective incorporation of histone variants into chromatin, eukaryotic cells can adjust their transcriptional profile in response to molecular needs. We used the nuclear dimorphic ciliate protozoan, Tetrahymena thermophila, as a model system to investigate the dynamics of H3 variant function. H3.3 is the ancestral H3 variant with key roles in regulating chromatin states and transcription. Functional proteomics and immunofluorescence analyses of H3.1 and H3.3 revealed a conserved role for Nrp1 and Asf1 histone chaperones in nuclear influx of histones. Cac2 and Hir1 have distinct localization patterns during different stages of the Tetrahymena life cycle and suggests that both Cac2 and Hir1 might be dispensable for the replication-dependent and -independent deposition of H3.1 and H3.3, respectively. ChIP-seq experiments in growing Tetrahymena show H3.3 enrichment over promoters, genes bodies, and transcription termination sites of highly transcribed genes. H3.3 knockout followed by RNA-seq reveals large-scale transcriptional alterations in functionally important genes. Our results provide an evolutionary perspective on H3.3’s conserved role in maintaining the transcriptional landscape of cells and on the emergence of specialized chromatin assembly pathways.
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Project description:Conjugation of ubiquitin (Ub) to numerous substrate proteins regulates virtually all cellular processes. Eight distinct ubiquitin polymer linkages specifying different functional outcomes are generated in cells. However, the roles of some atypical poly-ubiquitin topologies, in particular linkages via lysine 27 (K27), remain poorly understood due to a lack of tools for their specific detection and manipulation. Here, we adapted a cell-based ubiquitin replacement strategy to enable selective and conditional abrogation of K27-linked ubiquitylation, revealing that this ubiquitin linkage type is essential for proliferation of human cells. We demonstrate that K27-linked ubiquitylation is predominantly a nuclear modification whose ablation deregulates nuclear ubiquitylation dynamics and impairs cell cycle progression in an epistatic manner with inactivation of the ATPase p97/VCP. Moreover, we show that a p97-proteasome pathway model substrate (Ub(G76V)-GFP) is directly modified by K27-linked ubiquitylation, and that disabling the formation of K27-linked ubiquitin signals or blocking their decoding via overexpression of the K27 linkage-specific binder UCHL3 impedes Ub(G76V)-GFP turnover at the level of p97 function. Our findings suggest a critical role of K27-linked ubiquitylation in supporting cell fitness by facilitating p97-dependent processing of ubiquitylated nuclear proteins.
2022-04-14 | PXD023579 | Pride