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Mutations disrupting histone methylation have different effects on replication timing in S. pombe centromere.

ABSTRACT: The fission yeast pericentromere comprises repetitive sequence elements packaged into heterchromatin marked by histone H3K9 methylation and Swi6 binding. Transient disruption of Swi6 during S phase allows a period of RNA synthesis which programs the RNAi machinery to maintain histone methylation. However, Swi6 is also required for early replication timing. We show that not only Swi6 but also the chromodomain protein Chp1 are delocalized during S phase. Different from loss of swi6, mutations that disrupt histone methylation in the centromere, chp1? and clr4?, undergo early DNA replication. However, timing is modestly delayed in RNAi mutants dcr1? or rdp1?, while hrr1? mutants resemble swi6? in their replication delay. Finally, we show that recruitment of RNA polymerase II in the centromere occurs independently of replication. These different effects indicate that replication timing is not simply linked to histone methylation.

SUBMITTER: Li PC

PROVIDER: S-EPMC3641051 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

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Mutations disrupting histone methylation have different effects on replication timing in S. pombe centromere.

Li Pao-Chen PC Green Marc D MD Forsburg Susan L SL

PloS one 20130501 5

The fission yeast pericentromere comprises repetitive sequence elements packaged into heterchromatin marked by histone H3K9 methylation and Swi6 binding. Transient disruption of Swi6 during S phase allows a period of RNA synthesis which programs the RNAi machinery to maintain histone methylation. However, Swi6 is also required for early replication timing. We show that not only Swi6 but also the chromodomain protein Chp1 are delocalized during S phase. Different from loss of swi6, mutations that ...[more]

PMID: 23658693

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