title: The Paf1 complex factors Leo1 and Paf1 promote local histone turnover to modulate chromatin states in fission yeast.
abstract: The maintenance of open and repressed chromatin states is crucial for the regulation of gene expression. To study the genes involved in maintaining chromatin states, we generated a random mutant library in Schizosaccharomyces pombe and monitored the silencing of reporter genes inserted into the euchromatic region adjacent to the heterochromatic mating type locus. We show that Leo1-Paf1 [a subcomplex of the RNA polymerase II-associated factor 1 complex (Paf1C)] is required to prevent the spreading of heterochromatin into euchromatin by mapping the heterochromatin mark H3K9me2 using high-resolution genomewide ChIP (ChIP-exo). Loss of Leo1-Paf1 increases heterochromatin stability at several facultative heterochromatin loci in an RNAi-independent manner. Instead, deletion of Leo1 decreases nucleosome turnover, leading to heterochromatin stabilization. Our data reveal that Leo1-Paf1 promotes chromatin state fluctuations by enhancing histone turnover.
authors.affiliation: Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden.
authors.forename: Laia
authors.initials: L
authors.lastname: Sadeghi
authors.affiliation: Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden.
authors.forename: Punit
authors.initials: P
authors.lastname: Prasad
authors.affiliation: Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden karl.ekwall@ki.se amikamc@ekmd.huji.ac.il peter.svensson@ki.se.
authors.forename: Karl
authors.initials: K
authors.lastname: Ekwall
authors.affiliation: Department of Microbiology and Molecular Genetics, IMRIC The Hebrew University-Hadassah Medical School, Jerusalem, Israel karl.ekwall@ki.se amikamc@ekmd.huji.ac.il peter.svensson@ki.se.
authors.forename: Amikam
authors.initials: A
authors.lastname: Cohen
authors.affiliation: Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden karl.ekwall@ki.se amikamc@ekmd.huji.ac.il peter.svensson@ki.se.
authors.forename: J Peter
authors.initials: JP
authors.lastname: Svensson
mesh_terms: D002467:Cell Nucleus / Q000378:metabolism; D002843:Chromatin / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D015723:Gene Library; D006570:Heterochromatin / Q000378:metabolism; D042421:Histone Code; D006657:Histones / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D009707:Nucleosomes / Q000378:metabolism; D034622:RNA Interference; D012568:Schizosaccharomyces / Q000235:genetics* / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism*
chemical_list: D002843:Chromatin; D006570:Heterochromatin; D006657:Histones; D009687:Nuclear Proteins; D009707:Nucleosomes; D029702:Schizosaccharomyces pombe Proteins
keywords: Epe1; Paf1C; heterochromatin; histone turnover; transcription