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

Fernando Rodrigo Rosas Bringas, Sonia Stinus, Pien de Zoeten, Marita Cohn, Michael Chang

eLife 2022 Jan 19

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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. © 2022, Rosas Bringas et al.

Citation

Fernando Rodrigo Rosas Bringas, Sonia Stinus, Pien de Zoeten, Marita Cohn, Michael Chang. Rif2 protects Rap1-depleted telomeres from MRX-mediated degradation in Saccharomyces cerevisiae. eLife. 2022 Jan 19;11