title: Sir2p exists in two nucleosome-binding complexes with distinct deacetylase activities.
abstract: The absolute requirement for the histone deacetylase activity of Sir2p in silencing coupled with the conservation of Sir2p-like proteins in larger eukaryotes suggests that this molecule plays an important role in gene regulation in all organisms. Here we report the purification and characterization of two Sir2p-containing protein complexes; one of which contains Sir4p and the other Net1p. The Sir4p-containing complex has an NAD-dependent histone deacetylase activity, while the Net1p-containing complex possesses deacetylase activity but only weak NAD-dependent histone deacetylase activity. Finally, we demonstrate that the Sir2p-containing complexes bind nucleosomes efficiently and partially restrict accessibility of the linker DNA to enzymatic probes.
authors.affiliation: Unit on Chromatin and Transcription, NICHD/NIH, Building 18T, Room 106, 18 Library Drive, Bethesda, MD 20892, USA.
authors.forename: S
authors.initials: S
authors.lastname: Ghidelli
authors.forename: D
authors.initials: D
authors.lastname: Donze
authors.forename: N
authors.initials: N
authors.lastname: Dhillon
authors.forename: R T
authors.initials: RT
authors.lastname: Kamakaka
mesh_terms: D001665:Binding Sites; D018797:Cell Cycle Proteins; D005656:Fungal Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism / Q000502:physiology*; D006655:Histone Deacetylases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism / Q000502:physiology*; D016296:Mutagenesis; D009687:Nuclear Proteins / Q000378:metabolism; D009707:Nucleosomes / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae; D056565:Sirtuin 2; D037761:Sirtuins; D015534:Trans-Activators / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism / Q000502:physiology*
chemical_list: D018797:Cell Cycle Proteins; D005656:Fungal Proteins; C119300:Net1 protein, S cerevisiae; D009687:Nuclear Proteins; D009707:Nucleosomes; D011993:Recombinant Fusion Proteins; C084122:SIR3 protein, S cerevisiae; C061573:SIR4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae; D015534:Trans-Activators; C087778:SIR2 protein, S cerevisiae; D056565:Sirtuin 2; D037761:Sirtuins; D006655:Histone Deacetylases