Sim3 shares some common roles with the histone chaperone Asf1 in fission yeast

An H3/H4 histone chaperone, Asf1, plays an essential role in maintaining genomic stability in many species, including fission yeast. Here, we showed that overexpression of a CENP-A chaperone Sim3 suppressed the temperature sensitive phenotype of asf1-33 and asf1-30 mutants and the defect in chromatin structure, and prevented the accumulation of DNA damage in asf1-33 mutants at high temperatures. Furthermore, asf1-33 and Delta sim3 were synthetic lethal. Consistent with this, shutdown of sim3 expression in asf1-33 Delta sim3 double mutants that contained extragenic sim3 resulted in growth retardation. In addition, the Delta sim3 mutant displayed sensitivity to thiabendazol and hydroxyurea, which suggests that Sim3 plays a general role in maintaining chromatin structure. Our results suggest a possibility that Sim3 functions as a histone chaperone. (C) 2012 Federation of European Biochemical Societies. Published by Elsevier B. V. All rights reserved.