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Ku‐deficient yeast strains exhibit alternative states of silencing competence
Author(s) -
Maillet Laurent,
Gaden Florence,
Brevet Vanessa,
Fourel Geneviève,
Martin Sophie G,
Dubrana Karine,
Gasser Susan M,
Gilson Eric
Publication year - 2001
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.1093/embo-reports/kve044
Subject(s) - gene silencing , telomere , biology , nucleoplasm , saccharomyces cerevisiae , subtelomere , genetics , psychological repression , locus (genetics) , exoribonuclease , heterochromatin , epigenetics , microbiology and biotechnology , chromatin , gene , rnase p , cytoplasm , nucleolus , rna , gene expression
In Saccharomyces cerevisiae , efficient silencer function requires telomere proximity, i.e. compartments of the nucleoplasm enriched in silencing factors. Accordingly, silencers located far from telomeres function inefficiently. We show here that cells lacking yKu balance between two mitotically stable states of silencing competence. In one, a partial delocalization of telomeres and silencing factors throughout the nucleoplasm correlates with enhanced silencing at a non‐telomeric locus, while in the other, telomeres retain their focal pattern of distribution and there is no repression at the non‐telomeric locus, as observed in wild‐type cells. The two states also differ in their level of residual telomeric silencing. These findings indicate the existence of a yKu‐independent pathway of telomere clustering and Sir localization. Interestingly, this pathway appears to be under epigenetic control.