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Paf1 complex factors, Leo1 and Paf1, promote local histone turnover to modulate chromatin states in fission yeast [ChIP-exo]

ABSTRACT: Maintenance of open and repressed chromatin states is crucial for regulation of gene expression. To study the genes involved in maintaining chromatin states we generated a random mutant library using the Hermes transposon mutagenesis system in fission yeast Schizosacchromyces pombe. The silencing of reporter genes inserted in the euchromatic region adjacent to the heterochromatic mating type locus was monitored. We identified Leo1-Paf1, a subcomplex of the RNA Polymerase II Associated Factor 1 Complex (Paf1C), required to prevent spreading of heterochromatin into euchromatin. Through high-resolution genome-wide ChIP (ChIP-exo) we mapped the heterochromatin mark H3K9me2 in leo1∆ cells. Loss of Leo1-Paf1 led to increased heterochromatin stability at several facultative heterochromatin loci. The RNAi machinery is the major pathway for heterochromatin formation in S. pombe. However, small RNA sequencing showed that heterochromatin assembly in leo1∆ cells was RNAi-independent. By examining histone turnover rate in leo1∆ cells, we showed that deletion of Leo1 decreased nucleosome turnover, which led to heterochromatin spreading. Our data revealed that Leo1-Paf1 promotes chromatin state fluctuations by enhancing histone turnover.

ORGANISM(S): Schizosaccharomyces pombe

PROVIDER: GSE66939 | GEO | 2015/10/18

SECONDARY ACCESSION(S): PRJNA278409

REPOSITORIES: GEO

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Paf1 complex factors, Leo1 and Paf1, promote local histone turnover to modulate chromatin states in fission yeast [ncRNA-Seq]

Project description:Maintenance of open and repressed chromatin states is crucial for regulation of gene expression. To study the genes involved in maintaining chromatin states we generated a random mutant library using the Hermes transposon mutagenesis system in fission yeast Schizosacchromyces pombe. The silencing of reporter genes inserted in the euchromatic region adjacent to the heterochromatic mating type locus was monitored. We identified Leo1-Paf1, a subcomplex of the RNA Polymerase II Associated Factor 1 Complex (Paf1C), required to prevent spreading of heterochromatin into euchromatin. Through high-resolution genome-wide ChIP (ChIP-exo) we mapped the heterochromatin mark H3K9me2 in leo1∆ cells. Loss of Leo1-Paf1 led to increased heterochromatin stability at several facultative heterochromatin loci. The RNAi machinery is the major pathway for heterochromatin formation in S. pombe. However, small RNA sequencing showed that heterochromatin assembly in leo1∆ cells was RNAi-independent. By examining histone turnover rate in leo1∆ cells, we showed that deletion of Leo1 decreased nucleosome turnover, which led to heterochromatin spreading. Our data revealed that Leo1-Paf1 promotes chromatin state fluctuations by enhancing histone turnover.

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