Characterization of the role of serine phosphorylation on CenH3 function in Saccharomyces cerevisae
Final Report Abstract
Centromeres are the sites of assembly of the kinetochores, where the chromatids are linked to the microtubules for sister chromatid segregation during cell division. Centromeres are characterized by the presence of the histone H3 variant CENP-A (termed Cse4 in Saccharomyces cerevisiae). Here, we investigated the function of serine 33 phosphorylation of Cse4 (Cse4-S33ph) in S. cerevisiae, which lies within the essential N-terminal domain (END) of the extended Cse4 N-terminus. Significantly, we identified mutations in histone H4 acetylation sites (H4-K5, 8, 12R) to cause a temperature-sensitive growth defect with mutations in Cse4- S33 and sensitivity to nocodazole and hydroxyurea. This was interesting in light of the observation that defects in H4 acetylation cause a defect in deposition of CENP-A in higher eukaryotes. In agreement with this, the absence of Cse4-S33ph reduced the levels of Cse4 at centromeric sequences, suggesting that Cse4 deposition is defective in the absence of S33 phosphorylation. We furthermore identified synthetic genetic interactions of cse4-S33 mutations with histone H2A-E57A and H2A-L66A, which both cause a reduced interaction with the histone chaperone FACT and reduced H2A/ H2B levels in chromatin, again supporting the notion that a combined defect of H2A/ H2B and Cse4 deposition causes centromeric defects. Altogether, our data highlight the importance of correct histone deposition in building a functional centromeric nucleosome and suggests a role for Cse4-S33ph in this process.
Publications
-
(2018) A role for CENP-A/Cse4 phosphorylation on serine 33 in deposition at the centromere. FEMS yeast research 18 (1)
Hoffmann, Gesine; Samel-Pommerencke, Anke; Weber, Jan; Cuomo, Alessandro; Bonaldi, Tiziana; Ehrenhofer-Murray, Ann E.
