Nucleolar KKE/D repeat proteins Nop56p and Nop58p interact with Nop1p and are required for ribosome biogenesis.
AUTOR(ES)
Gautier, T
RESUMO
Different point mutations in the nucleolar protein fibrillarin (Nop1p in Saccharomyces cerevisiae) can inhibit different steps in ribosome synthesis. A screen for mutations that are synthetically lethal (sl) with the nop1-5 allele, which inhibits pre-rRNA processing, identified NOP56. An independent sl mutation screen with nop1-3, which inhibits pre-rRNA methylation, identified a mutation in NOP58. Strikingly, Nop56p and Nop58p are highly homologous (45% identity). Both proteins were found to be essential and localized to the nucleolus. A temperature-sensitive lethal mutant allele, nop56-2, inhibited many steps in pre-rRNA processing, particularly on the pathway of 25S/5.8S rRNA synthesis, and led to defects in 60S subunit assembly. Epitope-tagged constructs show that both Nop56p and Nop58p are associated with Noplp in complexes, Nop56p and Nop1p exhibiting a stoichiometric association. These physical interactions presumably underlie the observed sl phenotypes. Well-conserved homologs are present in a range of organisms, including humans (52% identity between human hNop56p and yeast Nop56p), suggesting that these complexes have been conserved in evolution.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=232565Documentos Relacionados
- Spb1p Is a Yeast Nucleolar Protein Associated with Nop1p and Nop58p That Is Able To Bind S-Adenosyl-l-Methionine In Vitro
- Nip7p Interacts with Nop8p, an Essential Nucleolar Protein Required for 60S Ribosome Biogenesis, and the Exosome Subunit Rrp43p
- Saccharomyces cerevisiae Nip7p is required for efficient 60S ribosome subunit biogenesis.
- Novel Stress-responsive Genes EMG1 and NOP14 Encode Conserved, Interacting Proteins Required for 40S Ribosome Biogenesis
- Yeast Krr1p Physically and Functionally Interacts with a Novel Essential Kri1p, and Both Proteins Are Required for 40S Ribosome Biogenesis in the Nucleolus