Overlapping Regulation of CenH3 Localization and Histone H3 Turnover by CAF-1 and HIR Proteins in Saccharomyces cerevisiae.

Accurate chromosome segregation is dependent on the centromere-specific histone H3 isoform known generally as CenH3, or as Cse4 in budding yeast. Cytological experiments have shown that Cse4 appears at extra-centromeric loci in yeast cells deficient for both the CAF-1 and HIR histone H3/H4 deposition complexes, consistent with increased non-disjunction in ...
these double mutant cells. Here, we examined molecular aspects of this Cse4 mislocalization. Genome-scale chromatin immunoprecipitation analyses demonstrated broader distribution of Cse4 outside of centromeres in cac1Δhir1Δ double mutant cells that lack both CAF-1 and HIR complexes than in either single mutant. However, cytological localization showed that the essential inner kinetochore component Mif2 (CENP-C) was not recruited to extracentromeric Cse4, suggesting that neocentromere formation does not occur in cac1Δhir1Δ double mutant cells. We also observed that rpb1-1 mutants displayed a modestly-increased Cse4 half-life at non-permissive temperatures, suggesting that turnover of Cse4 is partially dependent on Pol II transcription. We used genome-scale assays to demonstrate that the CAF-1 and HIR complexes independently stimulate replication-independent histone H3 turnover rates. We discuss ways in which altered histone exchange kinetics may affect eviction of Cse4 from non-centromeric loci.
Genetics
Date: Oct. 13, 2010
Download Curated Data For This Publication
109153
Switch View:
  • Interactions 1