Rif2 protects Rap1-depleted telomeres from MRX-mediated degradation in Saccharomyces cerevisiae

eLife

Marita Cohn¹  Fernando Rodrigo Rosas Bringas²  Pien de Zoeten²  Michael Chang²  Sonia Stinus² 

[1] Department of Biology, Lund University, Lund, Sweden;European Research Institute for the Biology of Ageing, University Medical Center Groningen, Groningen, Netherlands;

关键词: Rap1;    Rif2;    Ku complex;    telomere;    telomerase;    tlc1-tm;    S. cerevisiae;   

DOI  :  10.7554/eLife.74090

来源: eLife Sciences Publications, Ltd

【 摘 要 】

Rap1 is the main protein that binds double-stranded telomeric DNA in Saccharomyces cerevisiae. Examination of the telomere functions of Rap1 is complicated by the fact that it also acts as a transcriptional regulator of hundreds of genes and is encoded by an essential gene. In this study, we disrupt Rap1 telomere association by expressing a mutant telomerase RNA subunit (tlc1-tm) that introduces mutant telomeric repeats. tlc1-tm cells grow similar to wild-type cells, although depletion of Rap1 at telomeres causes defects in telomere length regulation and telomere capping. Rif2 is a protein normally recruited to telomeres by Rap1, but we show that Rif2 can still associate with Rap1-depleted tlc1-tm telomeres, and that this association is required to inhibit telomere degradation by the MRX complex. Rif2 and the Ku complex work in parallel to prevent tlc1-tm telomere degradation; tlc1-tm cells lacking Rif2 and the Ku complex are inviable. The partially redundant mechanisms may explain the rapid evolution of telomere components in budding yeast species.

【 授权许可】

CC BY