Nop53p, an essential nucleolar protein that interacts with Nop17p and Nip7p, is required for pre-rRNA processing in Saccharomyces cerevisiae.
In eukaryotes, pre-rRNA processing depends on a large number of nonribosomal trans-acting factors that form large and intriguingly organized complexes. A novel nucleolar protein, Nop53p, was isolated by using Nop17p as bait in the yeast two-hybrid system. Nop53p also interacts with a second nucleolar protein, Nip7p. A carbon source-conditional strain with the NOP53 coding sequence under the control of the GAL1 promoter did not grow in glucose-containing medium, showing the phenotype of an essential gene. Under nonpermissive conditions, the conditional mutant strain showed rRNA biosynthesis defects, leading to an accumulation of the 27S and 7S pre-rRNAs and depletion of the mature 25S and 5.8S mature rRNAs. Nop53p did not interact with any of the exosome subunits in the yeast two-hybrid system, but its depletion affects the exosome function. In pull-down assays, protein A-tagged Nop53p coprecipitated the 27S and 7S pre-rRNAs, and His-Nop53p also bound directly 5.8S rRNA in vitro, which is consistent with a role for Nop53p in pre-rRNA processing.
Granato
Daniela C
DC
Department of Biochemistry, Chemistry Institute, University of São Paulo, Brazil.
Gonzales
Fernando A
FA
Luz
Juliana S
JS
Cassiola
Flávia
F
Machado-Santelli
Glaucia M
GM
Oliveira
Carla C
CC
D000595:Amino Acid Sequence; D001483:Base Sequence; D005800:Genes, Fungal; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D012322:RNA Precursors / Q000235:genetics / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D012331:RNA, Fungal / Q000235:genetics / Q000378:metabolism; D012340:RNA, Ribosomal, 5.8S / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012269:Ribosomal Proteins / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D020798:Two-Hybrid System Techniques
C107936:NIP7 protein, S cerevisiae; C504135:Nop53 protein, S cerevisiae; D009687:Nuclear Proteins; C497702:PIH1 protein, S cerevisiae; D012322:RNA Precursors; D012331:RNA, Fungal; D012340:RNA, Ribosomal, 5.8S; D011993:Recombinant Fusion Proteins; D012269:Ribosomal Proteins; D029701:Saccharomyces cerevisiae Proteins