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H3-K27me3


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  • High histone acetylation and decreased polycomb repressive complex 2 member levels regulate gene specific transcriptional changes during early embryonic stem cell differe ... 17525233

    Histone modifications play a crucial role during embryonic stem (ES) cell differentiation. During differentiation, binding of polycomb repressive complex 2 (PRC2), which mediates trimethylation of lysine 27 on histone H3 (K27me3), is lost on developmental genes that are transcriptionally induced. We observed a global decrease in K27me3 in as little as 3 days after differentiation of mouse ES cells induced by retinoic acid (RA) treatment. The global levels of the histone K27 methyltransferase EZH2 also decreased with RA treatment. A loss of EZH2 binding and K27me3 was observed locally on PRC2 target genes induced after 3 days of RA, including Nestin. In contrast, direct RA-responsive genes that are rapidly induced, such as Hoxa1, showed a loss of EZH2 binding and K27me3 after only a few hours of RA treatment. Following differentiation induced by leukemia inhibitor factor (LIF) withdrawal without RA, Hoxa1 was not transcriptionally activated. Small interfering RNA-mediated knockdown of EZH2 resulted in loss of K27me3 during LIF withdrawal, but the Hoxa1 gene remained transcriptionally silent after loss of this repressive mark. Induction of histone hyperacetylation overrode the repressive K27me3 modification and resulted in Hoxa1 gene expression. Together, these data show that there are multiple temporal phases of derepression of PRC2 target genes during ES cell differentiation and that other epigenetic marks (specifically, increased acetylation of histones H3 and H4), in addition to derepression, are important for gene-specific transcriptional activation. This report demonstrates the temporal interplay of various epigenetic changes in regulating gene expression during early ES cell differentiation.
    Tipo de documento:
    Referencia
    Referencia del producto:
    3301

  • Differential sub-nuclear localisation of repressive and activating histone methyl modifications in P. falciparum. 19136073

    Post-translational histone modifications and sub-nuclear organization epigenetically influence gene regulation, especially those implicated in antigenic variation of Plasmodium falciparum. Here we screened for histone methylation modifications and determined, for the first time, their spatial nuclear localisation. Differential enrichment in sub-nuclear compartments, suggesting high local concentrations of particular methyl marks was observed. H3-K79me3 particularly, does not co-localise with already defined nuclear compartments, thus apparently defining a compartment not observed previously in other eukaryotes. Our data show the presence of discrete sub-nuclear zones enriched for histone methyl marks, pointing to the existence of specialized transcription factories and repressive regions in Plasmodium.
    Tipo de documento:
    Referencia
    Referencia del producto:
    07-549

  • Gene regulation and epigenetic remodeling in murine embryonic stem cells by c-Myc. 19915707

    The Myc oncoprotein, a transcriptional regulator involved in the etiology of many different tumor types, has been demonstrated to play an important role in the functions of embryonic stem (ES) cells. Nonetheless, it is still unclear as to whether Myc has unique target and functions in ES cells.To elucidate the role of c-Myc in murine ES cells, we mapped its genomic binding sites by chromatin-immunoprecipitation combined with DNA microarrays (ChIP-chip). In addition to previously identified targets we identified genes involved in pluripotency, early development, and chromatin modification/structure that are bound and regulated by c-Myc in murine ES cells. Myc also binds and regulates loci previously identified as Polycomb (PcG) targets, including genes that contain bivalent chromatin domains. To determine whether c-Myc influences the epigenetic state of Myc-bound genes, we assessed the patterns of trimethylation of histone H3-K4 and H3-K27 in mES cells containing normal, increased, and reduced levels of c-Myc. Our analysis reveals widespread and surprisingly diverse changes in repressive and activating histone methylation marks both proximal and distal to Myc binding sites. Furthermore, analysis of bulk chromatin from phenotypically normal c-myc null E7 embryos demonstrates a 70-80% decrease in H3-K4me3, with little change in H3-K27me3, compared to wild-type embryos indicating that Myc is required to maintain normal levels of histone methylation.We show that Myc induces widespread and diverse changes in histone methylation in ES cells. We postulate that these changes are indirect effects of Myc mediated by its regulation of target genes involved in chromatin remodeling. We further show that a subset of PcG-bound genes with bivalent histone methylation patterns are bound and regulated in response to altered c-Myc levels. Our data indicate that in mES cells c-Myc binds, regulates, and influences the histone modification patterns of genes involved in chromatin remodeling, pluripotency, and differentiation.
    Tipo de documento:
    Referencia
    Referencia del producto:
    07-449
    Nombre del producto:
    Anti-trimethyl-Histone H3 (Lys27) Antibody

  • Differentiation-dependent requirement of Tsix long non-coding RNA in imprinted X-chromosome inactivation. 24979243

    Imprinted X-inactivation is a paradigm of mammalian transgenerational epigenetic regulation resulting in silencing of genes on the paternally inherited X-chromosome. The preprogrammed fate of the X-chromosomes is thought to be controlled in cis by the parent-of-origin-specific expression of two opposing long non-coding RNAs, Tsix and Xist, in mice. Exclusive expression of Tsix from the maternal-X has implicated it as the instrument through which the maternal germline prevents inactivation of the maternal-X in the offspring. Here, we show that Tsix is dispensable for inhibiting Xist and X-inactivation in the early embryo and in cultured stem cells of extra-embryonic lineages. Tsix is instead required to prevent Xist expression as trophectodermal progenitor cells differentiate. Despite induction of wild-type Xist RNA and accumulation of histone H3-K27me3, many Tsix-mutant X-chromosomes fail to undergo ectopic X-inactivation. We propose a novel model of lncRNA function in imprinted X-inactivation that may also apply to other genomically imprinted loci.
    Tipo de documento:
    Referencia
    Referencia del producto:
    ABE44
    Nombre del producto:
    Anti-trimethyl Histone H3 (Lys27) Antibody

  • Histone posttranslational modifications and cell fate determination: lens induction requires the lysine acetyltransferases CBP and p300. 24038357

    Lens induction is a classical embryologic model to study cell fate determination. It has been proposed earlier that specific changes in core histone modifications accompany the process of cell fate specification and determination. The lysine acetyltransferases CBP and p300 function as principal enzymes that modify core histones to facilitate specific gene expression. Herein, we performed conditional inactivation of both CBP and p300 in the ectodermal cells that give rise to the lens placode. Inactivation of both CBP and p300 resulted in the dramatic discontinuation of all aspects of lens specification and organogenesis, resulting in aphakia. The CBP/p300(-/-) ectodermal cells are viable and not prone to apoptosis. These cells showed reduced expression of Six3 and Sox2, while expression of Pax6 was not upregulated, indicating discontinuation of lens induction. Consequently, expression of αB- and αA-crystallins was not initiated. Mutant ectoderm exhibited markedly reduced levels of histone H3 K18 and K27 acetylation, subtly increased H3 K27me3 and unaltered overall levels of H3 K9ac and H3 K4me3. Our data demonstrate that CBP and p300 are required to establish lens cell-type identity during lens induction, and suggest that posttranslational histone modifications are integral to normal cell fate determination in the mammalian lens.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • Genic and global functions for Paf1C in chromatin modification and gene expression in Arabidopsis. 18725930

    In budding yeast, intragenic histone modification is linked with transcriptional elongation through the conserved regulator Paf1C. To investigate Paf1C-related function in higher eukaryotes, we analyzed the effects of loss of Paf1C on histone H3 density and patterns of H3 methylated at K4, K27, and K36 in Arabidopsis genes, and integrated this with existing gene expression data. Loss of Paf1C did not change global abundance of H3K4me3 or H3K36me2 within chromatin, but instead led to a 3' shift in the distribution of H3K4me3 and a 5' shift in the distribution of H3K36me2 within genes. We found that genes regulated by plant Paf1C showed strong enrichment for both H3K4me3 and H3K27me3 and also showed a high degree of tissue-specific expression. At the Paf1C- and PcG-regulated gene FLC, transcriptional silencing and loss of H3K4me3 and H3K36me2 were accompanied by expansion of H3K27me3 into the promoter and transcriptional start regions and further enrichment of H3K27me3 within the transcribed region. These results highlight both genic and global functions for plant Paf1C in histone modification and gene expression, and link transcriptional activity with cellular memory.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • Regional control of histone H3 lysine 27 methylation in Neurospora. 23530226

    Trimethylated lysine 27 on histone H3 (H3K27me3) is present in Drosophila, Arabidopsis, worms, and mammals, but is absent from yeasts that have been examined. We identified and analyzed H3K27me3 in the filamentous fungus Neurospora crassa and in other Neurospora species. H3K27me3 covers 6.8% of the N. crassa genome, encompassing 223 domains, including 774 genes, all of which are transcriptionally silent. N. crassa H3K27me3-marked genes are less conserved than unmarked genes and only ∼35% of genes marked by H3K27me3 in N. crassa are also H3K27me3-marked in Neurospora discreta and Neurospora tetrasperma. We found that three components of the Neurospora Polycomb repressive complex 2 (PRC2)--[Su-(var)3-9; E(z); Trithorax] (SET)-7, embryonic ectoderm development (EED), and SU(Z)12 (suppressor of zeste12)--are required for H3K27me3, whereas the fourth component, Neurospora protein 55 (an N. crassa homolog of p55/RbAp48), is critical for H3K27me3 only at subtelomeric domains. Loss of H3K27me3, caused by deletion of the gene encoding the catalytic PRC2 subunit, set-7, resulted in up-regulation of 130 genes, including genes in both H3K27me3-marked and unmarked regions.
    Tipo de documento:
    Referencia
    Referencia del producto:
    07-449
    Nombre del producto:
    Anti-trimethyl-Histone H3 (Lys27) Antibody

  • Polycomb-like 3 promotes polycomb repressive complex 2 binding to CpG islands and embryonic stem cell self-renewal. 22438827

    Polycomb repressive complex 2 (PRC2) trimethylates lysine 27 of histone H3 (H3K27me3) to regulate gene expression during diverse biological transitions in development, embryonic stem cell (ESC) differentiation, and cancer. Here, we show that Polycomb-like 3 (Pcl3) is a component of PRC2 that promotes ESC self-renewal. Using mass spectrometry, we identified Pcl3 as a Suz12 binding partner and confirmed Pcl3 interactions with core PRC2 components by co-immunoprecipitation. Knockdown of Pcl3 in ESCs increases spontaneous differentiation, yet does not affect early differentiation decisions as assessed in teratomas and embryoid bodies, indicating that Pcl3 has a specific role in regulating ESC self-renewal. Consistent with Pcl3 promoting PRC2 function, decreasing Pcl3 levels reduces H3K27me3 levels while overexpressing Pcl3 increases H3K27me3 levels. Furthermore, chromatin immunoprecipitation and sequencing (ChIP-seq) reveal that Pcl3 co-localizes with PRC2 core component, Suz12, and depletion of Pcl3 decreases Suz12 binding at over 60% of PRC2 targets. Mutation of conserved residues within the Pcl3 Tudor domain, a domain implicated in recognizing methylated histones, compromises H3K27me3 formation, suggesting that the Tudor domain of Pcl3 is essential for function. We also show that Pcl3 and its paralog, Pcl2, exist in different PRC2 complexes but bind many of the same PRC2 targets, particularly CpG islands regulated by Pcl3. Thus, Pcl3 is a component of PRC2 critical for ESC self-renewal, histone methylation, and recruitment of PRC2 to a subset of its genomic sites.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • Histone demethylase JMJD3 is required for osteoblast differentiation in mice. 26302868

    JMJD3 (KDM6B) is an H3K27me3 demethylases and emerges as an important player in developmental processes. Although some evidence indicated the involvement of JMJD3 in osteoblast differentiation in vitro, its role as a whole in osteoblast differentiation and bone formation in vivo remains unknown. Here we showed that homozygous deletion of Jmjd3 resulted in severe delay of osteoblast differentiation and bone ossification in mice. By biochemical and genetical methods, we demonstrated that JMJD3 mediated RUNX2 transcriptional activity and cooperated with RUNX2 to promote osteoblast differentiation and bone formation in vivo. These results strongly demonstrated that JMJD3 is required for osteoblast differentiation and bone formation in mice.
    Tipo de documento:
    Referencia
    Referencia del producto:
    07-449
    Nombre del producto:
    Anti-trimethyl-Histone H3 (Lys27) Antibody

  • Epigenetic control of cell cycle-dependent histone gene expression is a principal component of the abbreviated pluripotent cell cycle. 22826438

    Self-renewal of human pluripotent embryonic stem cells proceeds via an abbreviated cell cycle with a shortened G(1) phase. We examined which genes are modulated in this abbreviated period and the epigenetic mechanisms that control their expression. Accelerated upregulation of genes encoding histone proteins that support DNA replication is the most prominent gene regulatory program at the G(1)/S-phase transition in pluripotent cells. Expedited expression of histone genes is mediated by a unique chromatin architecture reflected by major nuclease hypersensitive sites, atypical distribution of epigenetic histone marks, and a region devoid of histone octamers. We observed remarkable differences in chromatin structure--hypersensitivity and histone protein modifications--between human embryonic stem (hES) and normal diploid cells. Cell cycle-dependent transcription factor binding permits dynamic three-dimensional interactions between transcript initiating and processing factors at 5' and 3' regions of the gene. Thus, progression through the abbreviated G(1) phase involves cell cycle stage-specific chromatin-remodeling events and rapid assembly of subnuclear microenvironments that activate histone gene transcription to promote nucleosomal packaging of newly replicated DNA during stem cell renewal.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo