Chromatin assembly factor I and Hir proteins contribute to building functional kinetochores in S. cerevisiae (original) (raw)

  1. Judith A. Sharp1,2,
  2. Alexa A. Franco1,2,
  3. Mary Ann Osley3, and
  4. Paul D. Kaufman1,2,4
  5. 1Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA; 2University of California, Berkeley, Department of Molecular and Cell Biology, Berkeley, California 94720, USA; 3Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131, USA

Abstract

Budding yeast centromeres are comprised of ∼125-bp DNA sequences that direct formation of the kinetochore, a specialized chromatin structure that mediates spindle attachment to chromosomes. We report here a novel role for the histone deposition complex chromatin assembly factor I (CAF-I) in building centromeric chromatin. The contribution of CAF-I to kinetochore function overlaps that of the Hir proteins, which have also been implicated in nucleosome formation and heterochromatic gene silencing. cacΔ hirΔ double mutant cells lacking both CAF-I and Hir proteins are delayed in anaphase entry in a spindle assembly checkpoint-dependent manner. Further, cacΔ and_hirΔ_ deletions together cause increased rates of chromosome missegregation, genetic synergies with mutations in kinetochore protein genes, and alterations in centromeric chromatin structure. Finally, CAF-I subunits and Hir1 are enriched at centromeres, indicating that these proteins make a direct contribution to centromeric chromatin structures.

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