title: A physical interaction between Gar1p and Rnt1pi is required for the nuclear import of H/ACA small nucleolar RNA-associated proteins.
abstract: During rRNA biogenesis, multiple RNA and protein substrates are modified and assembled through the coordinated activity of many factors. In Saccharomyces cerevisiae, the double-stranded RNA nuclease Rnt1p and the H/ACA snoRNA pseudouridylase complex participate in the transformation of the nascent pre-rRNA transcript into 35S pre-rRNA. Here we demonstrate the binding of a component of the H/ACA complex (Gar1p) to Rnt1p in vivo and in vitro in the absence of other factors. In vitro, Rnt1p binding to Gar1p is mutually exclusive of its RNA binding and cleavage activities. Mutations in Rnt1p that disrupt Gar1p binding do not inhibit RNA cleavage in vitro but slow RNA processing, prevent nucleolar localization of H/ACA snoRNA-associated proteins, and reduce pre-rRNA pseudouridylation in vivo. These results demonstrate colocalization of various components of the rRNA maturation complex and suggest a mechanism that links rRNA pseudouridylation and cleavage factors.
authors.affiliation: Groupe ARN, Département de Microbiologie et d'Infectiologie, Faculté de Médecine, Université de Sherbrooke, Sherbrooke, Québec, Canada J1H 5N4.
authors.forename: Annie
authors.initials: A
authors.lastname: Tremblay
authors.forename: Bruno
authors.initials: B
authors.lastname: Lamontagne
authors.forename: Mathieu
authors.initials: M
authors.lastname: Catala
authors.forename: Yeung
authors.initials: Y
authors.lastname: Yam
authors.forename: Stephanie
authors.initials: S
authors.lastname: Larose
authors.forename: Liam
authors.initials: L
authors.lastname: Good
authors.forename: Sherif Abou
authors.initials: SA
authors.lastname: Elela
mesh_terms: D000595:Amino Acid Sequence; D002467:Cell Nucleus / Q000378:metabolism; D004722:Endoribonucleases / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D006836:Hydro-Lyases; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D019913:Nuclear Localization Signals / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport; D012322:RNA Precursors / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D012335:RNA, Ribosomal / Q000378:metabolism; D020537:RNA, Small Nucleolar / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism; D043244:Ribonuclease III; D017411:Ribonucleoproteins, Small Nuclear; D020718:Ribonucleoproteins, Small Nucleolar; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D020798:Two-Hybrid System Techniques
chemical_list: D005656:Fungal Proteins; D008869:Microtubule-Associated Proteins; D019913:Nuclear Localization Signals; D009687:Nuclear Proteins; D012322:RNA Precursors; D012335:RNA, Ribosomal; D020537:RNA, Small Nucleolar; D016601:RNA-Binding Proteins; D017411:Ribonucleoproteins, Small Nuclear; D020718:Ribonucleoproteins, Small Nucleolar; D029701:Saccharomyces cerevisiae Proteins; C069628:NHP2 protein, S cerevisiae; C073180:GAR1 protein, S cerevisiae; D004722:Endoribonucleases; C468367:RNT1 protein, S cerevisiae; D043244:Ribonuclease III; D006836:Hydro-Lyases; C082278:CBF5 protein, S cerevisiae