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Cohabitation of insulators and silencing elements in yeast subtelomeric regions
Author(s) -
Fourel Geneviève,
Revardel Emmanuelle,
Koering Catherine Elaine,
Gilson Éric
Publication year - 1999
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/18.9.2522
Subject(s) - biology , subtelomere , genetics , cohabitation , gene silencing , saccharomyces cerevisiae , yeast , evolutionary biology , telomere , gene , political science , law
In budding yeast, the telomeric DNA is flanked by a combination of two subtelomeric repetitive sequences, the X and Y′ elements. We have investigated the influence of these sequences on telomeric silencing. The telomere‐proximal portion of either X or Y′ dampened silencing when located between the telomere and the reporter gene. These elements were named STARs, for s ub t elomeric a nti‐silencing r egions. STARs can also counteract silencer‐driven repression at the mating‐type HML locus. When two STARs bracket a reporter gene, its expression is no longer influenced by surrounding silencing elements, although these are still active on a second reporter gene. In addition, an intervening STAR uncouples the silencing of neighboring genes. STARs thus display the hallmarks of insulators. Protection from silencing is recapitulated by multimerized oligonucleotides representing Tbf1p‐ and Reb1p‐binding sites, as found in STARs. In contrast, sequences located more centromere proximal in X and Y′ elements reinforce silencing. They can promote silencing downstream of an insulated expressed domain. Overall, our results suggest that the silencing emanating from telomeres can be propagated in a discontinuous manner via a series of subtelomeric relay elements.