The Ku subunit of telomerase binds Sir4 to recruit telomerase to lengthen telomeres in S. cerevisiae

eLife

Evan P Hass¹  David C Zappulla¹ 

[1] Department of Biology, Johns Hopkins University, Baltimore, United States;

关键词: telomerase;    telomere;    yeast;    S. cerevisiae;    transcriptional silencing;    Ku;   

DOI  :  10.7554/eLife.07750

来源: DOAJ

【 摘 要 】

In Saccharomyces cerevisiae and in humans, the telomerase RNA subunit is bound by Ku, a ring-shaped protein heterodimer best known for its function in DNA repair. Ku binding to yeast telomerase RNA promotes telomere lengthening and telomerase recruitment to telomeres, but how this is achieved remains unknown. Using telomere-length analysis and chromatin immunoprecipitation, we show that Sir4 – a previously identified Ku-binding protein that is a component of telomeric silent chromatin – is required for Ku-mediated telomere lengthening and telomerase recruitment. We also find that specifically tethering Sir4 directly to Ku-binding-defective telomerase RNA restores otherwise-shortened telomeres to wild-type length. These findings suggest that Sir4 is the telomere-bound target of Ku-mediated telomerase recruitment and provide one mechanism for how the Sir4-competing Rif1 and Rif2 proteins negatively regulate telomere length in yeast.

【 授权许可】

Unknown