Telomeric chromatin modulates replication timing near chromosome ends

AUTOR(ES)
FONTE

Cold Spring Harbor Laboratory Press

RESUMO

Saccharomyces cerevisiae telomeric DNA replicates late in S phase, and telomeric genes are transcriptionally silent. Transcriptional repression of telomere-proximal genes results from silent chromatin initiating at the chromosome end, but the relationship between telomeric chromatin and DNA replication is unknown. Mutations in SIR3, a silent chromatin component, cause telomeric DNA on chromosome V to replicate much earlier because of earlier initiation of a nearby replication origin, the Y′ ARS. A second telomere-proximal ARS, from an X element, does not act as an origin in a wild-type strain, whereas in a sir3 cell it does. We conclude that telomeric chromatin has a Sir3-dependent inhibitory effect on DNA replication.

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