title: Naf1 p is a box H/ACA snoRNP assembly factor.
abstract: Box H/ACA small nucleolar ribonucleoprotein particles (snoRNPs) contain four essential proteins, Cbf5p, Gar1p, Nhp2p, and Nop10p, each of which, with the exception of Gar1p, is required for box H/ACA snoRNA accumulation. Database searches identified a novel essential protein, which we termed Naf1p, with a region of homology to the RNA-binding domain of Gar1p and other features in common with hnRNP-like proteins. Naf1p is localized to the nucleus and is not a stable component of the H/ACA snoRNPs, but it is required for the accumulation of all box H/ACA snoRNAs. This requirement is not at the level of snoRNA transcription initiation or termination. Naf1 p shows in vitro RNA-binding activity and also binds directly to Cbf5p and Nhp2p. Naf1p was shown to bind to the CTD in vivo in a two-hybrid assay, and the phosphorylated CTD, but not the nonphosphorylated CTD, was shown to precipitate tagged Naf1p from a cell lysate. We propose that Naf1 p is recruited to the CTD of RNA polymerase II and binds to nascent box H/ACA snoRNAs promoting snoRNP assembly.
authors.affiliation: Wellcome Trust Centre for Cell Biology, Swann Building, King's Buildings, University of Edinburgh, Edinburgh EH9 3JR, UK.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Fatica
authors.forename: Mensur
authors.initials: M
authors.lastname: Dlakić
authors.forename: David
authors.initials: D
authors.lastname: Tollervey
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001665:Binding Sites; D002467:Cell Nucleus / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D006836:Hydro-Lyases / Q000235:genetics / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D012319:RNA Polymerase II / Q000235:genetics / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional; D012335:RNA, Ribosomal / Q000378:metabolism; D020537:RNA, Small Nucleolar / Q000096:biosynthesis; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D017411:Ribonucleoproteins, Small Nuclear / Q000235:genetics / Q000378:metabolism; D020718:Ribonucleoproteins, Small Nucleolar / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic; D015003:Yeasts / Q000235:genetics / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D008869:Microtubule-Associated Proteins; D009687:Nuclear Proteins; D012335:RNA, Ribosomal; D020537:RNA, Small Nucleolar; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; D017411:Ribonucleoproteins, Small Nuclear; D020718:Ribonucleoproteins, Small Nucleolar; D029701:Saccharomyces cerevisiae Proteins; C069628:NHP2 protein, S cerevisiae; C073180:GAR1 protein, S cerevisiae; D012319:RNA Polymerase II; D006836:Hydro-Lyases; C082278:CBF5 protein, S cerevisiae