Deletion ofMEC1suppresses replicative senescence of thecdc13-2mutant inSaccharomyces cerevisiae

Abstract

AbstractInSaccharomyces cerevisiae, telomerase recruitment to telomeres depends on a direct interaction between Cdc13, a protein that binds single-stranded telomeric DNA, and the Est1 subunit of telomerase. Thecdc13-2allele disrupts telomerase association with telomeres, resulting in progressive telomere shortening and replicative senescence. The Mec1/ATR kinase is both a positive and negative regulator of telomerase activity, and is required for the cell cycle arrest in telomerase-deficient senescent cells. In this study, we find that deletion ofMEC1suppresses the replicative senescence ofcdc13-2. This suppression is dependent on telomerase, indicating that Mec1 antagonizes telomerase-mediated telomere extension incdc13-2cells to promote senescence.