Mus musculus
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA175035 | ENA |
REPOSITORIES: ENA
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Project description:Here we report that the histone variant macroH2A acts as a barrier to induced pluripotency. Using fibroblasts isolated from macroH2A double knockout mice, we observed enhanced reprogramming efficiency compared to fibroblasts from wild type animals. We further show that macroH2A isoforms act synergistically in this process. Genomic analysis in wild type fibroblasts reveals that macroH2A1 and H3K27me3 domains co-localize and occupy pluripotency genes. While the absence of macroH2A does not affect H3K27me3 in fibroblasts, macroH2A1 is highly enriched at a set of Utx target genes that are reactivated early during iPS reprogramming. Mononucleosomes from Dermal Fibroblasts (from wt and macroH2A1 and macroH2A2 double knockout mice) were isolated and ChIP'd with mH2A1, H3K27me3 and H3K27ac antibodies. DNA from Input and ChIP samples was purified and sequenced on Illumina's Hiseq.
2013-03-01 | E-GEOD-40813 | biostudies-arrayexpress
Project description:Here we report that the histone variant macroH2A acts as a barrier to induced pluripotency. Using fibroblasts isolated from macroH2A double knockout mice, we observed enhanced reprogramming efficiency compared to fibroblasts from wild type animals. We further show that macroH2A isoforms act synergistically in this process. Genomic analysis in wild type fibroblasts reveals that macroH2A1 and H3K27me3 domains co-localize and occupy pluripotency genes. While the absence of macroH2A does not affect H3K27me3 in fibroblasts, macroH2A1 is highly enriched at a set of Utx target genes that are reactivated early during iPS reprogramming.
2013-03-01 | GSE40813 | GEO
Project description:Transcription factor-induced reprogramming of somatic cells to pluripotency is a very inefficient process, probably due to the existence of important epigenetic barriers that are imposed during differentiation and that contribute to preserve cell identity. In an effort to decipher the molecular nature of these barriers, we followed a genome-wide approach, in which we identified macro histone variants (macroH2A) as highly expressed in human somatic cells but downregulated after reprogramming to pluripotency, as well as strongly induced during differentiation. Knock down of macro histone variants in human keratinocytes increased the efficiency of reprogramming to pluripotency, while overexpression had opposite effects. Genome-wide occupancy profiles show that in human keratinocytes macroH2A.1 preferentially occupies genes that are expressed at low levels and are marked with H3K27me3, including pluripotency-related genes and bivalent developmental regulators, at which its presence prevents the regain of H3K4me2 during reprogramming, over imposing an additional layer of repression that preserves cell identity. Gemone wide occupancy of HA:macroH2A.1 in human keratinocytes
2013-04-03 | E-GEOD-44400 | biostudies-arrayexpress
Project description:Transcription factor-induced reprogramming of somatic cells to pluripotency is a very inefficient process, probably due to the existence of important epigenetic barriers that are imposed during differentiation and that contribute to preserve cell identity. In an effort to decipher the molecular nature of these barriers, we followed a genome-wide approach, in which we identified macro histone variants (macroH2A) as highly expressed in human somatic cells but downregulated after reprogramming to pluripotency, as well as strongly induced during differentiation. Knock down of macro histone variants in human keratinocytes increased the efficiency of reprogramming to pluripotency, while overexpression had opposite effects. Genome-wide occupancy profiles show that in human keratinocytes macroH2A.1 preferentially occupies genes that are expressed at low levels and are marked with H3K27me3, including pluripotency-related genes and bivalent developmental regulators, at which its presence prevents the regain of H3K4me2 during reprogramming, over imposing an additional layer of repression that preserves cell identity.
2013-04-03 | GSE44400 | GEO
Project description:Eukaryotic chromatin structure is highly conserved, with the canonical histone proteins revealing only small sequence changes across species. Yet, all vertebrates exhibit three much larger histone H2A variants, macroH2A. A distinctive feature of these atypical histones is the globular macrodomain module, which can bind metabolites and is connected to the histone fold through a flexible linker. MacroH2A variants impact heterochromatin organization, transcription regulation and establish a barrier for cellular reprogramming. However, the mechanisms of how these large H2A variants are incorporated into chromatin and the identity of any chaperones required for histone deposition have remained elusive. Here, we developed a split-GFP-based cellular readout for histone incorporation and conducted a genome-wide mutagenesis screen in haploid human cells to identify proteins that regulate macroH2A dynamics. We identified and validated the histone chaperone ANP32B as a regulator of macroH2A chromatin deposition. ANP32B associates with macroH2A in cells and in vitro binds to histones with low nanomolar affinity. In vitro nucleosome assembly assays show that ANP32B stimulates deposition of macroH2A-H2B and not of H2A-H2B onto tetraso me. In cells, depletion of ANP32B in cells strongly affects global macroH2A deposition, revealing ANP32B as a macroH2A chaperone. Our study highlights the power of haploid cell functional genomics coupled with cellular imaging to identify factors that are required for chromatin plasticity and diversity.
2023-11-07 | GSE241387 | GEO
Project description:Genetic loss-of-function studies in development, cancer and somatic cell reprogramming have suggested that the group of macroH2A histone variants might function through stabilizing the differentiated state by a yet unknown mechanism. Here, we present results demonstrating that macroH2A variants have a major function in maintaining nuclear organization and heterochromatin architecture. Specifically, we find that a substantial amount of macroH2A is associated with heterochromatic repeat sequences. We further identify macroH2A on sites of interstitial heterochromatin decorated by H3K9me3. Loss of macroH2A leads to major defects in nuclear organization including reduced nuclear circularity, disruption of nucleoli and a global loss of dense heterochromatin. Domains formed by repeat sequences when depleted of macroH2A are disorganized, expanded and fragmented and mildly re-expressed. On the molecular level we find that macroH2A is required for the interaction of repeat sequences with the nucleostructural protein Lamin B1. Taken together our results argue that a major function of macroH2A histone variants is to link nucleosome composition to higher order chromatin architecture.
2017-03-21 | GSE58175 | GEO
Project description:The establishment and maintenance of cellular identity rely upon the precise coordination of regulatory pathways culminating to the proper execution of cell type-specific gene expression programs. Generation of induced pluripotent stem cells (iPSCs) from highly specialized cell types provides an excellent model system to study how cells maintain their stability through the functional interplay of transcription factors and chromatin structure, and how they can change identity, especially in the context of disease. Previous studies have shown that chromatin structure safeguards cell identity by acting as a barrier to reprogramming. Here, we investigated the mechanisms of how the histone variant macroH2A inhibits reprogramming by interfering with the mesenchyme to epithelial transition, a step that is a prerequisite for reprogramming of mouse embryonic fibroblasts. We found that each of the macroH2A isoforms regulates the expression of defined sets of genes, whose overall function is to stabilize the mesenchyme phenotype, thus resisting reprogramming. We identified a novel gene network (MSCN, mesenchyme network) composed of 63 macroH2A-regulated genes encoding proteins of the extracellular matrix, cell membrane, cytoplasmic signal integrators and the transcriptional regulators Id2 and Snai2, all of which can function as key controllers of the mesenchyme phenotype. Functional studies including ChIP-seq and KD experiments using any one of the individual macroH2A isoforms revealed an isoform-specific combinatorial targeting of the genes that reconstruct the MSCN. Our findings established that the combinatorial macroH2A targeting of the MSCN components safeguards cell identity and demonstrated its pivotal role in maintaining the differentiated cell phenotype by generating robustness in gene expression programs to resist cellular reprogramming.
2023-06-21 | GSE215884 | GEO
Project description:The establishment and maintenance of cellular identity rely upon the precise coordination of regulatory pathways culminating to the proper execution of cell type-specific gene expression programs. Generation of induced pluripotent stem cells (iPSCs) from highly specialized cell types provides an excellent model system to study how cells maintain their stability through the functional interplay of transcription factors and chromatin structure, and how they can change identity, especially in the context of disease. Previous studies have shown that chromatin structure safeguards cell identity by acting as a barrier to reprogramming. Here, we investigated the mechanisms of how the histone variant macroH2A inhibits reprogramming by interfering with the mesenchyme to epithelial transition, a step that is a prerequisite for reprogramming of mouse embryonic fibroblasts. We found that each of the macroH2A isoforms regulates the expression of defined sets of genes, whose overall function is to stabilize the mesenchyme phenotype, thus resisting reprogramming. We identified a novel gene network (MSCN, mesenchyme network) composed of 63 macroH2A-regulated genes encoding proteins of the extracellular matrix, cell membrane, cytoplasmic signal integrators and the transcriptional regulators Id2 and Snai2, all of which can function as key controllers of the mesenchyme phenotype. Functional studies including ChIP-seq and KD experiments using any one of the individual macroH2A isoforms revealed an isoform-specific combinatorial targeting of the genes that reconstruct the MSCN. Our findings established that the combinatorial macroH2A targeting of the MSCN components safeguards cell identity and demonstrated its pivotal role in maintaining the differentiated cell phenotype by generating robustness in gene expression programs to resist cellular reprogramming.
2023-06-21 | GSE215883 | GEO
Project description:MacroH2As core histone variants have a unique structure that includes C-terminal nonhistone domain. MacroH2As are highly conserved in vertebrates, and are thought to regulate gene expression. However the nature of genes regulated by macroH2As and the biological significance of macroH2As for the organism remain unclear. Here we examine macroH2A function in vivo by knocking out both macroH2A1 and macroH2A2 in the mouse. We used microarrays to examine how the absence of macroH2A.1 and macroH2A.2 histone variants affect gene expression fasted adult mouse liver.
2014-10-15 | GSE57088 | GEO
Project description:MacroH2As core histone variants have a unique structure that includes C-terminal nonhistone domain. MacroH2As are highly conserved in vertebrates, and are thought to regulate gene expression. However the nature of genes regulated by macroH2As and the biological significance of macroH2As for the organism remain unclear. Here we examine macroH2A function in vivo by knocking out both macroH2A1 and macroH2A2 in the mouse. We used microarrays to examine how the absence of macroH2A.1 and macroH2A.2 histone variants affect gene expression late fetal mouse liver.
2014-10-15 | GSE57086 | GEO