title: The interaction of Alba, a conserved archaeal chromatin protein, with Sir2 and its regulation by acetylation.
abstract: The conserved Sir2 family of proteins has protein deacetylase activity that is dependent on NAD (the oxidized form of nicotinamide adenine dinucleotide). Although histones are one likely target for the enzymatic activity of eukaryotic Sir2 proteins, little is known about the substrates and roles of prokaryotic Sir2 homologs. We reveal that an archaeal Sir2 homolog interacts specifically with the major archaeal chromatin protein, Alba, and that Alba exists in acetylated and nonacetylated forms. Furthermore, we show that Sir2 can deacetylate Alba and mediate transcriptional repression in a reconstituted in vitro transcription system. These data provide a paradigm for how Sir2 family proteins influence transcription and suggest that modulation of chromatin structure by acetylation arose before the divergence of the archaeal and eukaryotic lineages.
authors.affiliation: Medical Research Council (MRC) Cancer Cell Unit, The Hutchison/MRC Research Centre, Hills Road, Cambridge, CB2 2QH, UK. sdb@mole.bio.cam.ac.uk
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Bell
authors.forename: Catherine H
authors.initials: CH
authors.lastname: Botting
authors.forename: Benjamin N
authors.initials: BN
authors.lastname: Wardleworth
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Jackson
authors.forename: Malcolm F
authors.initials: MF
authors.lastname: White
mesh_terms: D000107:Acetylation; D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry* / Q000378:metabolism*; D002843:Chromatin / Q000378:metabolism*; D004247:DNA / Q000378:metabolism; D019848:Gene Expression Regulation, Archaeal; D006655:Histone Deacetylases / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae; D056565:Sirtuin 2; D037761:Sirtuins; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D016944:Sulfolobus / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013698:Templates, Genetic; D015534:Trans-Activators / Q000737:chemistry / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D019843:Archaeal Proteins; D002843:Chromatin; D011993:Recombinant Fusion Proteins; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae; D015534:Trans-Activators; D004247:DNA; C087778:SIR2 protein, S cerevisiae; D056565:Sirtuin 2; D037761:Sirtuins; D006655:Histone Deacetylases