Project description:A Trithorax-group (TrxG) protein ASH1 selectively dimethylates histone H3 lysine 36 (H3K36) and is required for expression of Hox genes. Genome-wide targets and molecular functions of ASH1, however, have remained elusive. Here we report ChIP-seq analysis of ASH1 targets in the human genome using a leukemia cell line K562. We identified 4,596 ASH1 binding sites, 2,502 of which are in the coding region, mostly in a proximity of promoters. Remaining half of the ASH1 binding sites are in the intergenic region. Analysis of histone methyation patterns revealed that a majority of ASH1 bidning sites are closely associated not only with trimethylated H3K36 (H3K36me3) but also with H3K9me3, shedding light for the first time to H3K36/H3K9 double methylation domains. Of note, an H3K9 methyltransferase SETDB1 is enriched in the ASH1 bidning sites, whereas EZH2 but not SUZ12 of the Polycomb Repression Complex 2 (PRC2) is present in bivalent domains. In addition, a small subset of ASH1 targets bear H3K4me3 and colocalize with RNA polymerase II. These select targets are highly enriched for regulators of gene expression, such as CXXC1, WHSC2/NELFA, and a battery of zinc finger proteins, suggesting that ASH1 might acts as a master regulator of gene expression.
Project description:The Drosophila Trithorax group (TrxG) protein ASH1 remains associated with mitotic chromatin through mechanisms that are poorly understood. ASH1 dimethylates histone H3 at lysine 36 via its SET domain. Here we identify domains of the TrxG protein ASH1 that are required for mitotic chromatin attachment in living Drosophila. Quantitative live imaging demonstrates that ASH1 requires AT hooks and the BAH domain but not the SET domain for full chromatin binding in metaphase, and that none of these domains are essential for interphase binding. Genetic experiments show that disruptions of the AT hooks and the BAH domain together, but not deletion of the SET domain alone, are lethal. Transcriptional profiling demonstrates that intact ASH1 AT hooks and the BAH domain are required to maintain expression levels of a specific set of genes, including several involved in cell identity and survival. This study identifies in vivo roles for specific ASH1 domains in mitotic binding, gene regulation and survival that are distinct from its functions as a histone methyltransferase.
Project description:Ash1 is a Trithorax Group (TrxG) protein with histone methyl transferase activity that is associated with gene activation. Here we use ChIP-chip to determine the occupancy of Ash1 at promoters in murine embryonic stem cells.
Project description:Ash1 is a classic Trithorax group protein possessing an H3K36-specific histone methyltransferase activity. Ash1 plays a critical role in antagonizing Polycomb silencing and its loss-of-function mutations lead to inactivation of certain Hox genes and homeotic transformation. Here, we report the purification of Ash1 complex with the identification of two novel subunits, Mrg15 and Nurf55. Interestingly, Mrg15 stimulates the enzymatic activity of Ash1 in vitro, and such stimulation is independent of the chromo domain of Mrg15. In vivo, Mrg15 is recruited by Ash1 to their common target genes and Mrg15 is essential for the proper deposition of H3K36me2 at these regions.
Project description:Ash1 is a Trithorax Group (TrxG) protein with histone methyl transferase activity that is associated with gene activation. Here we use ChIP-chip to determine the occupancy of Ash1 at promoters in murine embryonic stem cells. This dataset includes singlet ChIP-chip data targeting Ash1 in murine Embryonic stem cells.
Project description:The absent, small or homeotic discs 2 (ash2) gene, a member of the trithorax Group (trxG) of transcriptional regulators, is functionally related to ash1. However, ASH2 and ASH1 belong to distinct multimeric complexes of unknown composition and it is unclear how they act to regulate transcription. In this study, examination of gene expression profiles in wing imaginal discs from ash2 and ash1 mutants revealed their transcriptomes are very similar and correlate with wing phenotypes. Keywords: loss of function analysis
Project description:Mrg15 allosterically activates Ash1’s H3K36 methyltransferase activity and facilitates Ash1’s trithorax group protein function in Drosophila
Project description:The mechanisms that recruit the major Polycomb-group (PcG) complexes PRC1 and PRC2 to target sites in vertebrate cells are not well understood. Building on recent studies that have determined a reciprocal relationship between DNA methylation and Polycomb activity, we demonstrate that in methylation deficient ES cells CpG density, combined with antagonistic effects of H3K9me3 and H3K36me3, redirect PcG complexes to pericentric heterochromatin and gene rich domains. In this experiment we have assayed the genomic distribution of H3K9me3 and H3K36me3 marks,
Project description:Trithorax group (TrxG) proteins counteract Polycomb silencing by an as yet uncharacterized mechanism. A well-known member of the TrxG is the histone methyltransferase Absent, Small, or Homeotic discs 1 (ASH1). In Drosophila ASH1 is needed for the maintenance of Hox gene expression throughout development, which is tightly coupled to preservation of cell identity. In order to understand the molecular function of ASH1 in this process, we performed affinity purification of tandem-tagged ASH1 followed by mass spectrometry (AP-MS) and identified FSH, another member of the TrxG as interaction partner. Here we provide genome-wide chromatin maps of both proteins based on ChIP-seq.
Project description:Trithorax group (TrxG) proteins counteract Polycomb silencing by an as yet uncharacterized mechanism. A well-known member of the TrxG is the histone methyltransferase Absent, Small, or Homeotic discs 1 (ASH1). In Drosophila ASH1 is needed for the maintenance of Hox gene expression throughout development, which is tightly coupled to preservation of cell identity. In order to understand the molecular function of ASH1 in this process, we performed affinity purification of tandem-tagged ASH1 followed by mass spectrometry (AP-MS) and identified FSH, another member of the TrxG as interaction partner. Here we provide genome-wide chromatin maps of both proteins based on ChIP-seq. Our Dataset comprises of 4 ChIP-seq samples using chromatin from S2 cells which was immunoprecipitated, using antibodies against Ash1, FSH-L and FSH-SL.