The box H+ACA snoRNAs carry Cbf5p, the putative rRNA pseudouridine synthase
AUTOR(ES)
Lafontaine, Denis L.J.
FONTE
Cold Spring Harbor Laboratory Press
RESUMO
Many or all of the sites of pseudouridine (Ψ) formation in eukaryotic rRNA are selected by site-specific base-pairing with members of the box H + ACA class of small nucleolar RNAs (snoRNAs). Database searches previously identified strong homology between the rat nucleolar protein Nap57p, its yeast homolog Cbf5p, and the Escherichia coli Ψ synthase truB/P35. We therefore tested whether Cbf5p is required for synthesis of Ψ in the yeast rRNA. After genetic depletion of Cbf5p, formation of Ψ in the pre-rRNA is dramatically inhibited, resulting in accumulation of the unmodified rRNA. Protein A-tagged Cbf5p coprecipitates all tested members of the box H + ACA snoRNAs but not box C + D snoRNAs or other RNA species. Genetic depletion of Cbf5p leads to depletion of all box H + ACA snoRNAs. These include snR30, which is required for pre-rRNA processing. Depletion of Cbf5p also results in a pre-rRNA processing defect similar to that seen on depletion of snR30. We conclude that Cbf5p is likely to be the rRNA Ψ synthase and is an integral component of the box H + ACA class of snoRNPs, which function to target the enzyme to its site of action.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=316522Documentos Relacionados
- Binding of L7Ae protein to the K-turn of archaeal snoRNAs: a shared RNA binding motif for C/D and H/ACA box snoRNAs in Archaea
- Evolutionary appearance of genes encoding proteins associated with box H/ACA snoRNAs: Cbf5p in Euglena gracilis, an early diverging eukaryote, and candidate Gar1p and Nop10p homologs in archaebacteria
- A Well-Connected and Conserved Nucleoplasmic Helicase Is Required for Production of Box C/D and H/ACA snoRNAs and Localization of snoRNP Proteins
- Stable expression in yeast of the mature form of human telomerase RNA depends on its association with the box H/ACA small nucleolar RNP proteins Cbf5p, Nhp2p and Nop10p
- Human Box H/ACA Pseudouridylation Guide RNA Machinery†