title: Genome-wide chromatin occupancy analysis reveals a role for ASH2 in transcriptional pausing.
abstract: An important mechanism for gene regulation involves chromatin changes via histone modification. One such modification is histone H3 lysine 4 trimethylation (H3K4me3), which requires histone methyltranferase complexes (HMT) containing the trithorax-group (trxG) protein ASH2. Mutations in ash2 cause a variety of pattern formation defects in the Drosophila wing. We have identified genome-wide binding of ASH2 in wing imaginal discs using chromatin immunoprecipitation combined with sequencing (ChIP-Seq). Our results show that genes with functions in development and transcriptional regulation are activated by ASH2 via H3K4 trimethylation in nearby nucleosomes. We have characterized the occupancy of phosphorylated forms of RNA Polymerase II and histone marks associated with activation and repression of transcription. ASH2 occupancy correlates with phosphorylated forms of RNA Polymerase II and histone activating marks in expressed genes. Additionally, RNA Polymerase II phosphorylation on serine 5 and H3K4me3 are reduced in ash2 mutants in comparison to wild-type flies. Finally, we have identified specific motifs associated with ASH2 binding in genes that are differentially expressed in ash2 mutants. Our data suggest that recruitment of the ASH2-containing HMT complexes is context specific and points to a function of ASH2 and H3K4me3 in transcriptional pausing control.
authors.affiliation: Departament de Genètica i Institut de Biomedicina (IBUB), Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain.
authors.forename: Sílvia
authors.initials: S
authors.lastname: Pérez-Lluch
authors.forename: Enrique
authors.initials: E
authors.lastname: Blanco
authors.forename: Albert
authors.initials: A
authors.lastname: Carbonell
authors.forename: Debasish
authors.initials: D
authors.lastname: Raha
authors.forename: Michael
authors.initials: M
authors.lastname: Snyder
authors.forename: Florenci
authors.initials: F
authors.lastname: Serras
authors.forename: Montserrat
authors.initials: M
authors.lastname: Corominas
mesh_terms: D000818:Animals; D002843:Chromatin / Q000378:metabolism*; D004330:Drosophila / Q000235:genetics* / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D049750:Genome, Insect; D006657:Histones / Q000737:chemistry / Q000378:metabolism; D008239:Lysine / Q000378:metabolism; D008745:Methylation; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D012319:RNA Polymerase II / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015533:Transcriptional Activation
chemical_list: D002843:Chromatin; D029721:Drosophila Proteins; D006657:Histones; D009687:Nuclear Proteins; D014157:Transcription Factors; C103604:ash2 protein, Drosophila; D012319:RNA Polymerase II; D008239:Lysine