FACT-mediated depletion of macroH2A-nucleosome regulates the cell response of macrophage
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PROVIDER: PRJNA1044766 | ENA |
REPOSITORIES: ENA
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Project description:The histone variant macroH2A has been shown to generally associate with transcriptionally silent chromatin states. However, how macroH2A regulates the chromatin structure and functions in transcriptional process still remains elusive at the molecular level. In this study, we demonstrate that the incorporation of macroH2A does not affect the stability and the folding dynamics of nucleosome, but greatly impairs the FACT’s maintenance function at the nucleosome level. FACT can greatly impair the stability of macroH2A nucleosome, and quickly deplete the macroH2A nucleosome after the first unfolding process. Furthermore, we identify the key residue S139 of macroH2A, whose mutation can rescue the FACT’s function to maintain nucleosome integrity. Genome-wide analyses show that S139 mutation in macroH2A reshapes the position of macroH2A and regulates the stimulation-induced transcription in macrophage. Our findings provide mechanistic insights of how histone variant macroH2A coregulates with FACT at the nucleosome level and functions in cell response of macrophage in immunity.
2025-05-01 | GSE248551 | GEO
Project description:The mechanisms whereby the crucial pluripotency transcription factor Oct4 regulates target gene expression are incompletely understood. Using an assay system based on partially differentiated embryonic stem cells, we show that Oct4 opposes accumulation of local H3K9me2, and subsequent Dnmt3a-mediated DNA methylation. Upon binding DNA, Oct4 recruits the histone lysine demethylase Jmjd1c. ChIP timecourse experiments identify a stepwise Oct4 mechanism involving Jmjd1c recruitment and H3K9me2 demethylation, transient FACT complex recruitment, and nucleosome depletion. Genome-wide and targeted ChIP confirms binding of newly-synthesized Oct4, together with Jmjd1c and FACT, to the Pou5f1 enhancer and a small number of other Oct4 targets, including the Nanog promoter. Histone demethylation is required for both FACT recruitment and H3 depletion. Jmjd1c is required to induce endogenous Oct4 expression and fully reprogram fibroblasts to pluripotency, indicating that the assay system identifies functional Oct4 cofactors. These findings indicate that Oct4 sequentially recruits activities that catalyze histone demethylation and depletion. Examination of transcription factor occupancy in cells with newly synthesized Oct4.
2015-01-23 | E-GEOD-65192 | biostudies-arrayexpress
Project description:Nucleosome assembly in vivo requires assembly factors, such as histone chaperones, to bind to histones and mediate their deposition onto DNA. In yeast, the essential histone chaperone FACT (FAcilitates Chromatin Transcription) functions in nucleosome assembly and H2A-H2B deposition during transcription elongation and DNA replication. Recent studies have identified candidate histone residues that mediate FACT binding to histones, but it is not known which histone residues are important for FACT to deposit histones onto DNA during nucleosome assembly. In this study, we report that the histone H2B repression (HBR) domain within the H2B N-terminal tail is important for histone deposition by FACT. Deletion of the HBR domain causes significant defects in histone occupancy in the yeast genome, particularly at HBR-repressed genes, and a pronounced increase in H2A-H2B dimers that remain bound to FACT in vivo. Moreover, the HBR domain is required for purified FACT to efficiently assemble recombinant nucleosomes in vitro. We propose that the interaction between the highly basic HBR domain and DNA plays an important role in stabilizing the nascent nucleosome during the process of histone H2A-H2B deposition by FACT. 6 samples, 2 inputs and 4 ChIP samples for histone H2B (2 for wild-type and 2 for an H2B â30-37 mutant)
2016-08-10 | E-GEOD-80831 | biostudies-arrayexpress
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 mechanisms whereby the crucial pluripotency transcription factor Oct4 regulates target gene expression are incompletely understood. Using an assay system based on partially differentiated embryonic stem cells, we show that Oct4 opposes accumulation of local H3K9me2, and subsequent Dnmt3a-mediated DNA methylation. Upon binding DNA, Oct4 recruits the histone lysine demethylase Jmjd1c. ChIP timecourse experiments identify a stepwise Oct4 mechanism involving Jmjd1c recruitment and H3K9me2 demethylation, transient FACT complex recruitment, and nucleosome depletion. Genome-wide and targeted ChIP confirms binding of newly-synthesized Oct4, together with Jmjd1c and FACT, to the Pou5f1 enhancer and a small number of other Oct4 targets, including the Nanog promoter. Histone demethylation is required for both FACT recruitment and H3 depletion. Jmjd1c is required to induce endogenous Oct4 expression and fully reprogram fibroblasts to pluripotency, indicating that the assay system identifies functional Oct4 cofactors. These findings indicate that Oct4 sequentially recruits activities that catalyze histone demethylation and depletion.
2015-01-23 | GSE65192 | 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:Nucleosome assembly in vivo requires assembly factors, such as histone chaperones, to bind to histones and mediate their deposition onto DNA. In yeast, the essential histone chaperone FACT (FAcilitates Chromatin Transcription) functions in nucleosome assembly and H2A-H2B deposition during transcription elongation and DNA replication. Recent studies have identified candidate histone residues that mediate FACT binding to histones, but it is not known which histone residues are important for FACT to deposit histones onto DNA during nucleosome assembly. In this study, we report that the histone H2B repression (HBR) domain within the H2B N-terminal tail is important for histone deposition by FACT. Deletion of the HBR domain causes significant defects in histone occupancy in the yeast genome, particularly at HBR-repressed genes, and a pronounced increase in H2A-H2B dimers that remain bound to FACT in vivo. Moreover, the HBR domain is required for purified FACT to efficiently assemble recombinant nucleosomes in vitro. We propose that the interaction between the highly basic HBR domain and DNA plays an important role in stabilizing the nascent nucleosome during the process of histone H2A-H2B deposition by FACT.
2016-08-10 | GSE80831 | 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. Our gene expression studies indicate that macroH2A.1 and macroH2A.2 work together to regulate specific genes. In these studies we examine the distributions of macroH2A.1 and macroH2A.2 nucleosomes to determine if they are localized to the genes that show altered expression in macroH2A knockout mouse liver. MacroH2A.1 and macroH2A.2 nucleosomes prepared from ~ 50 fetal mouse livers were purified by thio-affinity chromatography. Five samples were sequenced: Thiopropyl Sepharose, Normal Liver - contains mononucleosomal DNA from macroH2A.1-containing nucleosomes; Activate Thiol Sepharose, Normal Liver - contains mononucleosomal DNA primarily from macroH2A.2-containing nucleosomes. Starting Material, Normal Liver - this is a reference samplefor the first two samples. It contains mononucleosomal DNA from bulk fetal liver chromatin. Activated Thiol Sepharose, Knockout Livers - this is a control sample that contains mononucleosomal DNA from non-macroH2A nucleosomes that contaminate the macroH2A.2 nucleosomes. This fraction was prepared from macroH2A1/2 double knockout fetal livers; Starting Material, Knockout Liver - this is a reference sample for the fourth sample. It contains mononucleosomal DNA from bulk chromatin prepared from macroH2A1/2 double knockout fetal livers.
2014-10-15 | E-GEOD-57796 | biostudies-arrayexpress
Project description:The mammalian FACT complex is a highly conserved histone chaperone with essential roles in transcription elongation, histone deposition, and maintenance of stem cell state. FACT is essential for viability in pluripotent cells and cancer cells, but otherwise dispensable for most mammalian cell types. FACT deletion or inhibition can block reprogramming of fibroblasts to induced pluripotent stem cells, yet the molecular mechanisms through which FACT regulates cell fate decisions remain unclear. To determine the mechanism by which FACT regulates stem cell identity, we used the auxin-inducible degron systems to deplete murine embryonic stem cells of FACT subunit SPT16 and subjected depleted cells to genome-wide factor localization, nascent transcription analyses, and genome-wide nucleosome profiling. Inducible depletion of SPT16 reveals a critical role in regulating targets of the master regulators of pluripotency: OCT4, KLF4, MYC, NANOG, and SOX2. Depletion of SPT16 leads to increased nucleosome occupancy at genomic loci occupied by these transcription factors, as well as gene-distal regulatory sites defined by DNaseI hypersensitivity. This heightened occupancy suggests a mechanism of nucleosome filling, wherein the sites typically maintained in an accessible state by FACT are occluded through loss of FACT-regulated nucleosome spacing. 20% of transcription arising from gene-distal regions bound by these factors is directly dependent on FACT, and putative gene targets of these non-coding RNAs are highly enriched for pluripotency in pathway analyses. Upon FACT depletion, transcription of Pou5f1 (OCT4), Sox2, and Nanog are downregulated, suggesting that FACT not only co-regulates expression of the encoded proteins’ targets, but also the pluripotency factors themselves. We find that FACT maintains cellular pluripotency through a complex regulatory network of both coding and non-coding transcription.
2023-07-13 | GSE237024 | GEO
Project description:The mammalian FACT complex is a highly conserved histone chaperone with essential roles in transcription elongation, histone deposition, and maintenance of stem cell state. FACT is essential for viability in pluripotent cells and cancer cells, but otherwise dispensable for most mammalian cell types. FACT deletion or inhibition can block reprogramming of fibroblasts to induced pluripotent stem cells, yet the molecular mechanisms through which FACT regulates cell fate decisions remain unclear. To determine the mechanism by which FACT regulates stem cell identity, we used the auxin-inducible degron systems to deplete murine embryonic stem cells of FACT subunit SPT16 and subjected depleted cells to genome-wide factor localization, nascent transcription analyses, and genome-wide nucleosome profiling. Inducible depletion of SPT16 reveals a critical role in regulating targets of the master regulators of pluripotency: OCT4, KLF4, MYC, NANOG, and SOX2. Depletion of SPT16 leads to increased nucleosome occupancy at genomic loci occupied by these transcription factors, as well as gene-distal regulatory sites defined by DNaseI hypersensitivity. This heightened occupancy suggests a mechanism of nucleosome filling, wherein the sites typically maintained in an accessible state by FACT are occluded through loss of FACT-regulated nucleosome spacing. 20% of transcription arising from gene-distal regions bound by these factors is directly dependent on FACT, and putative gene targets of these non-coding RNAs are highly enriched for pluripotency in pathway analyses. Upon FACT depletion, transcription of Pou5f1 (OCT4), Sox2, and Nanog are downregulated, suggesting that FACT not only co-regulates expression of the encoded proteins’ targets, but also the pluripotency factors themselves. We find that FACT maintains cellular pluripotency through a complex regulatory network of both coding and non-coding transcription.
2023-03-15 | GSE181622 | GEO