Study the role and function of HP1 in embryonic stem cells
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE210606 | GEO | 2023/08/31
REPOSITORIES: GEO
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Project description:Embryonic stem cells (ESCs) have a hyperdynamic chromatin structure characterized by fewer discrete foci of heterochromatin protein 1 family of proteins (HP1) compared to somatic cells. During reprogramming of somatic cells, depletion of HP1γ early, reduced, while depletion later, enhanced the generation of induced pluripotent stem cells (iPSCs); concomitant with a change from a centromeric to nucleoplasmic localization. To identify the interactome of HP1γ in different biochemical environment in ESCs, we compared protein complexes of HP1γ at 0.42M salt (Dignam et al, 1983), with micrococcal nuclease (MCN) digestion with 0.3M NaCl, and MCN with 0.5M NaCl. To understand the effectors of the change in localization, we isolated protein complexes containing HP1γ in ESCs and compared the profile to that in partially reprogrammed intermediates called pre-iPSCs. Given the differential distribution of the HP1 family in ESCs, we also compared the protein interactome of HP1γ in ESCs with that of HP1α and HP1β. In addition, we probed histone associations of HP1γ in ESCs further by querying the histone post-translational modifications that were detectable. The HP1 proteins themselves are decorated with multiple PTMs, several of which we have found to be novel. Taken together our results reveal the complex contribution of the HP1 proteins to pluripotency.
2017-12-13 | PXD006817 | Pride
Project description:The family of Heterochromatin Protein 1 (HP1) consists of highly conserved proteins, which have important functions in the nucleus of eukaryotic cells. In mammals there are three HP1 paralogs: HP1(alpha), Hp1(beta), and Hp1(gamma)They are encoded by the Cbx5, Cbx1, and Cbx3 genes, respectively. Hp1 and Hp1 stably interact with Chd4 and Adnp to form the ChAHP complex. In this project, Chd4, Adnp, and the three Cbx genes were endogenously tagged with a FLAG-Avi tag in mouse embryonic stem cells. The tagged proteins were subjected to tandem-affinity purification and analysis by mass spectrometry.
2018-05-22 | PXD006226 | Pride
Project description:The global impact of DNA methylation on alternative splicing is largely unknown. Using a genome-wide approach in wild-type and methylation-deficient embryonic stem cells, we found that DNA methylation can act both as an enhancer and as a silencer of splicing, and affects the splicing of more than 20% of alternative exons. These exons are characterized by distinct genetic and epigenetic signatures. Alternative splicing regulation of a subset of these exons can be explained by Heterochromatin protein 1 (HP1), which silences or enhances exon recognition in a position-dependent manner. We constructed an experimental system using site-specific targeting of a methylated/unmethylated gene, and demonstrate a direct causal relationship between DNA methylation and alternative splicing. HP1 regulates this geneM-bM-^@M-^Ys alternative splicing in a methylation-dependent manner by recruiting splicing factors to its methylated form. Our results demonstrate DNA methylation's significant global influence on mRNA splicing, and identify a specific mechanism of splicing regulation mediated by HP1. BS-seq on WT mouse ES cells (2 replicates), MNase-seq on WT and TKO cells (3 replicates), mRNA-seq on WT and TKO cells as well as HP1 knock-down cells (2 replicates for each sample)
2015-03-08 | E-GEOD-64910 | biostudies-arrayexpress
Project description:H3K9me3-heterochromatin, compacted by HP1 proteins, restricts transcription factor binding and functions as a barrier to cell fate changes in development and reprogramming1,2. To investigate principles underlying H3K9me3-heterochromatin maintenance in mammalian cells, we applied degron engineering3,4 on mouse ESCs to conditionally deplete all three H3K9me3-methyltransferases within one hour and found an unexpectedly dynamic nature of heterochromatin maintenance. Following H3K9me3 methyltransferases degradation, HP1β dissociates from heterochromatin within three hours, and transcription factors quickly access the de-compacted heterochromatin, activating transcription of their targets, which then promotes H3K9me3 decay. Both passive dilution and active removal contribute to the H3K9me3 decay. Mathematical modeling reveals distinct H3K9me3 heterochromatin states with diverse chromatin features which influence initial H3K9me3 levels and the stability of H3K9me3 domains, thereby expanding our understanding of distinct heterochromatin domains. Rampant transposable element de-repression interferes with transcription of poised early developmental and signaling genes outside H3K9me3-domains, highlighting the intricate roles of dynamic H3K9me3-heterochromatin maintenance in safeguarding developmental programs. Our findings deconvolve the hierarchical relationships between H3K9me3 marks, methyltransferases, HP1 and transcription factors to reveal principles of H3K9me3-heterochromatin maintenance and how its remodeling enables transcription and cell fate change.
2024-09-19 | GSE233040 | GEO
Project description:H3K9me3-heterochromatin, compacted by HP1 proteins, restricts transcription factor binding and functions as a barrier to cell fate changes in development and reprogramming1,2. To investigate principles underlying H3K9me3-heterochromatin maintenance in mammalian cells, we applied degron engineering3,4 on mouse ESCs to conditionally deplete all three H3K9me3-methyltransferases within one hour and found an unexpectedly dynamic nature of heterochromatin maintenance. Following H3K9me3 methyltransferases degradation, HP1β dissociates from heterochromatin within three hours, and transcription factors quickly access the de-compacted heterochromatin, activating transcription of their targets, which then promotes H3K9me3 decay. Both passive dilution and active removal contribute to the H3K9me3 decay. Mathematical modeling reveals distinct H3K9me3 heterochromatin states with diverse chromatin features which influence initial H3K9me3 levels and the stability of H3K9me3 domains, thereby expanding our understanding of distinct heterochromatin domains. Rampant transposable element de-repression interferes with transcription of poised early developmental and signaling genes outside H3K9me3-domains, highlighting the intricate roles of dynamic H3K9me3-heterochromatin maintenance in safeguarding developmental programs. Our findings deconvolve the hierarchical relationships between H3K9me3 marks, methyltransferases, HP1 and transcription factors to reveal principles of H3K9me3-heterochromatin maintenance and how its remodeling enables transcription and cell fate change.
2024-09-19 | GSE233039 | GEO
Project description:H3K9me3-heterochromatin, compacted by HP1 proteins, restricts transcription factor binding and functions as a barrier to cell fate changes in development and reprogramming1,2. To investigate principles underlying H3K9me3-heterochromatin maintenance in mammalian cells, we applied degron engineering3,4 on mouse ESCs to conditionally deplete all three H3K9me3-methyltransferases within one hour and found an unexpectedly dynamic nature of heterochromatin maintenance. Following H3K9me3 methyltransferases degradation, HP1β dissociates from heterochromatin within three hours, and transcription factors quickly access the de-compacted heterochromatin, activating transcription of their targets, which then promotes H3K9me3 decay. Both passive dilution and active removal contribute to the H3K9me3 decay. Mathematical modeling reveals distinct H3K9me3 heterochromatin states with diverse chromatin features which influence initial H3K9me3 levels and the stability of H3K9me3 domains, thereby expanding our understanding of distinct heterochromatin domains. Rampant transposable element de-repression interferes with transcription of poised early developmental and signaling genes outside H3K9me3-domains, highlighting the intricate roles of dynamic H3K9me3-heterochromatin maintenance in safeguarding developmental programs. Our findings deconvolve the hierarchical relationships between H3K9me3 marks, methyltransferases, HP1 and transcription factors to reveal principles of H3K9me3-heterochromatin maintenance and how its remodeling enables transcription and cell fate change.
2024-09-19 | GSE231845 | GEO
Project description:H3K9me3-heterochromatin, compacted by HP1 proteins, restricts transcription factor binding and functions as a barrier to cell fate changes in development and reprogramming1,2. To investigate principles underlying H3K9me3-heterochromatin maintenance in mammalian cells, we applied degron engineering3,4 on mouse ESCs to conditionally deplete all three H3K9me3-methyltransferases within one hour and found an unexpectedly dynamic nature of heterochromatin maintenance. Following H3K9me3 methyltransferases degradation, HP1β dissociates from heterochromatin within three hours, and transcription factors quickly access the de-compacted heterochromatin, activating transcription of their targets, which then promotes H3K9me3 decay. Both passive dilution and active removal contribute to the H3K9me3 decay. Mathematical modeling reveals distinct H3K9me3 heterochromatin states with diverse chromatin features which influence initial H3K9me3 levels and the stability of H3K9me3 domains, thereby expanding our understanding of distinct heterochromatin domains. Rampant transposable element de-repression interferes with transcription of poised early developmental and signaling genes outside H3K9me3-domains, highlighting the intricate roles of dynamic H3K9me3-heterochromatin maintenance in safeguarding developmental programs. Our findings deconvolve the hierarchical relationships between H3K9me3 marks, methyltransferases, HP1 and transcription factors to reveal principles of H3K9me3-heterochromatin maintenance and how its remodeling enables transcription and cell fate change.
2024-09-19 | GSE270213 | GEO
Project description:Methylated lysine 27 on histone H3 (H3K27me) marks repressed "facultative heterochromatin", including developmentally regulated genes in plants and animals. The mechanisms responsible for localization of H3K27me are largely unknown, perhaps in part because of the complexity of epigenetic regulatory networks. We used a relatively simple model organism bearing both facultative and constitutive heterochromatin, Neurospora crassa, to explore possible interactions between elements of heterochromatin. In higher eukaryotes, reductions of H3K9me3 and DNA methylation in constitutive heterochromatin have been variously reported to cause redistribution of H3K27me3. In Neurospora, we found that elimination of any member of the DCDC H3K9 methylation complex (DIM-5, DIM-7, CUL4, DDB1/DIM-8 or DIM-9) caused massive changes in the distribution of H3K27me; regions of facultative heterochromatin lost H3K27me3 while regions that are normally marked by H3K9me3 became methylated at H3K27. Elimination of DNA methylation by deletion of the DNA methyltransferase gene, dim-2, had no obvious effect on the distribution of H3K27me. Elimination of HP1, which "reads" H3K9me3, also caused major changes in the distribution of H3K27me, indicating that HP1 is important for normal localization of facultative heterochromatin. Because loss of HP1 caused redistribution of H3K27me2/3 but not H3K9me3, these normally non-overlapping marks became superimposed. Indeed, mass spectrometry revealed substantial cohabitation of H3K9me3 and H3K27me2 on H3 molecules from an hpo strain. Loss of H3K27me machinery (e.g. the methyltransferase SET-7) did not impact constitutive heterochromatin, but partially rescued the slow growth of the DCDC mutants, suggesting that the poor growth of these mutants is partly attributable to ectopic H3K27me. Altogether, our findings with Neurospora clarify interactions of facultative and constitutive heterochromatin in eukaryotes.
2015-11-03 | GSE68897 | GEO