title: Sir2p and Sas2p opposingly regulate acetylation of yeast histone H4 lysine16 and spreading of heterochromatin.
abstract: The Sir3 protein helps form telomeric heterochromatin by interacting with hypoacetylated histone H4 lysine 16 (H4-Lys16). The molecular nature of the heterochromatin boundary is still unknown. Here we show that the MYST-like acetyltransferase Sas2p is required for the acetylation (Ac) of H4-Lys16 in euchromatin. In a sas2Delta strain or a phenocopy Lys16Arg mutant, Sir3p spreads from roughly 3 kb to roughly 15 kb, causing hypoacetylation and repression of adjacent chromatin. We also found that disruption of Sir3p binding in a deacetylase-deficient Sir 2Delta strain can be suppressed by sas2Delta. These data indicate that opposing effects of Sir2p and Sas2p on acetylation of H4-Lys16 maintain the boundary at telomeric heterochromatin.
authors.affiliation: Department of Biological Chemistry, UCLA School of Medicine and the Molecular Biology Institute, Boyer Hall, University of California, Los Angeles, California 90095, USA.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Suka
authors.forename: Kunheng
authors.initials: K
authors.lastname: Luo
authors.forename: Michael
authors.initials: M
authors.lastname: Grunstein
mesh_terms: D000107:Acetylation; D000123:Acetyltransferases / Q000378:metabolism / Q000502:physiology*; D001120:Arginine; D002843:Chromatin / Q000378:metabolism; D006570:Heterochromatin / Q000737:chemistry / Q000378:metabolism*; D051548:Histone Acetyltransferases; D006655:Histone Deacetylases / Q000378:metabolism / Q000502:physiology*; D006657:Histones / Q000378:metabolism*; D008239:Lysine / Q000378:metabolism*; D009154:Mutation; D011233:Precipitin Tests; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism / Q000502:physiology*; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae / Q000378:metabolism / Q000502:physiology*; D056565:Sirtuin 2; D037761:Sirtuins / Q000378:metabolism / Q000502:physiology*; D016615:Telomere / Q000648:ultrastructure
chemical_list: D002843:Chromatin; D006570:Heterochromatin; D006657:Histones; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae; D001120:Arginine; D000123:Acetyltransferases; D051548:Histone Acetyltransferases; C469266:Sas2 protein, S cerevisiae; C087778:SIR2 protein, S cerevisiae; D056565:Sirtuin 2; D037761:Sirtuins; D006655:Histone Deacetylases; D008239:Lysine