Genomics

Dataset Information

297

Mediator promotes CENP-A incorporation at fission yeast centromeres [ChIP-seq]


ABSTRACT: At Schizosaccharomyces pombe centromeres, heterochromatin formation is required for de novo incorporation of the histone H3 variant CENP-A/Cnp1, which in turn directs kinetochore assembly and ultimately chromosome segregation during mitosis. Noncoding RNAs (ncRNAs) transcribed by RNA polymerase II (Pol II) directs heterochromatin formation via the RNAi machinery, but also through RNAiindependent RNA processing factors. Control of centromeric ncRNA transcription is therefore a key factor for proper centromere function. We here use transcriptional profiling, gene inactivation experiments, and chromatin immunoprecipitation analyses to demonstrate that the Mediator complex directs ncRNA transcription and regulates centromeric heterochromatin formation in fission yeast. Mediator co-localizes with Pol II at centromeres and loss of the Mediator subunit Med20 causes a dramatic increase in pericentromeric transcription and desilencing of the core centromere. As a consequence, heterochromatin formation is impaired both via the RNAi dependent and independent pathways, resulting in loss of CENP-A/Cnp1 from the core centromere, defect kinetochore function, and a severe chromosome segregation defect. Interestingly, the increased centromeric transcription observed in med20Δ appears to directly block CENP-A/Cnp1 incorporation and inhibition of Pol II transcription can suppress the observed phenotypes. Our data thus identify Mediator as a crucial regulator of ncRNA transcription at fission yeast centromeres and add another crucial layer of regulation to centromere function. 3 samples examined: wild type chromatin incubated with beads as the non antibody control, wild type chromatin incubated with RNA Polymerase II CTD domain antibody and Protein G beads, and TAP-Med7 cells chromatin incubated with IgG beads.

ORGANISM(S): Schizosaccharomyces pombe  

SUBMITTER: Claes Gustafsson   Marcela Davila Lopez  Xuefeng Zhu  Jonas O Carlsten 

PROVIDER: E-GEOD-35524 | ArrayExpress | 2012-11-06

SECONDARY ACCESSION(S): GSE35524SRP010743PRJNA156087

REPOSITORIES: GEO, ArrayExpress, ENA

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Publications

Mediator promotes CENP-a incorporation at fission yeast centromeres.

Carlsten Jonas O JO   Szilagyi Zsolt Z   Liu Beidong B   Lopez Marcela Davila MD   Szászi Erzsébet E   Djupedal Ingela I   Nyström Thomas T   Ekwall Karl K   Gustafsson Claes M CM   Zhu Xuefeng X  

Molecular and cellular biology 20120730 19


At Schizosaccharomyces pombe centromeres, heterochromatin formation is required for de novo incorporation of the histone H3 variant CENP-A(Cnp1), which in turn directs kinetochore assembly and ultimately chromosome segregation during mitosis. Noncoding RNAs (ncRNAs) transcribed by RNA polymerase II (Pol II) directs heterochromatin formation through not only the RNA interference (RNAi) machinery but also RNAi-independent RNA processing factors. Control of centromeric ncRNA transcription is theref  ...[more]

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