Sir2 and Reb1 antagonistically regulate nucleosome occupancy in subtelomeric X-elements and repress TERRAs by distinct mechanisms.

ABSTRACT: Telomere chromatin structure is pivotal for maintaining genome stability by regulating the binding of telomere-associated proteins and inhibiting the DNA damage response. In Saccharomyces cerevisiae, silent information regulator (Sir) proteins bind to terminal repeats and to subtelomeric X-elements, resulting in transcriptional silencing. Herein, we show that sir2 mutant strains display a specific loss of a nucleosome residing in the X-elements and that this deficiency is remarkably consistent between different telomeres. The X-elements contain several binding sites for the transcription factor Reb1 and we found that Sir2 and Reb1 compete for stabilizing/destabilizing this nucleosome, i.e. inactivation of Reb1 in a sir2 background reinstated the lost nucleosome. The telomeric-repeat-contai

SUBMITTER: Bauer SL 

PROVIDER: S-EPMC9531808 | biostudies-literature | 2022 Sep

REPOSITORIES: biostudies-literature