The Sirtuins Hst3 and Hst4p Preserve Genome Integrity by Controlling Histone H3 Lysine 56 Deacetylation

Ivana Celic, Hiroshi Masumoto, Wendell P. Griffith, Pamela Meluh, Robert J. Cotter, Jef D. Boeke, Alain Verreault

Research output: Contribution to journalArticlepeer-review


Background: Acetylation of histone H3 lysine 56 (K56Ac) occurs transiently in newly synthesized H3 during passage through S phase and is removed in G2. However, the physiologic roles and effectors of K56Ac turnover are unknown. Results: The sirtuins Hst3p and, to a lesser extent, Hst4p maintain low levels of K56Ac outside of S phase. In hst3 hst4 mutants, K56 hyperacetylation nears 100%. Residues corresponding to the nicotinamide binding pocket of Sir2p are essential for Hst3p function, and H3 K56 deacetylation is inhibited by nicotinamide in vivo. Rapid inactivation of Hst3/Hst4p prior to S phase elevates K56Ac to 50% in G2, suggesting that K56-acetylated nucleosomes are assembled genome-wide during replication. Inducible expression of Hst3p in G1 or G2 triggers deacetylation of mature chromatin. Cells lacking Hst3/Hst4p exhibit many phenotypes: spontaneous DNA damage, chromosome loss, thermosensitivity, and acute sensitivity to genotoxic agents. These phenotypes are suppressed by mutation of histone H3 K56 into a nonacetylatable residue or by loss of K56Ac in cells lacking the histone chaperone Asf1. Conclusions: Our results underscore the critical importance of Hst3/Hst4p in controlling histone H3 K56Ac and thereby maintaining chromosome integrity.

Original languageEnglish (US)
Pages (from-to)1280-1289
Number of pages10
JournalCurrent Biology
Issue number13
StatePublished - Jul 11 2006


  • DNA

ASJC Scopus subject areas

  • General Biochemistry, Genetics and Molecular Biology
  • General Agricultural and Biological Sciences


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