Site-Specific Pseudouridine Formation in Preribosomal RNA Is Guided by Small Nucleolar RNAs

• Published in: Cell Vol. 89; no. 5; pp. 799 - 809
• Main Authors: Ganot, Philippe, Bortolin, Marie-Line, Kiss, Tamás
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 30.05.1997
• Subjects: Base Composition; Base Sequence; Molecular Sequence Data; RNA Precursors - genetics; RNA, Small Nuclear - genetics; Saccharomyces cerevisiae; Saccharomyces cerevisiae - genetics; Uridine - genetics
• ISSN: 0092-8674; 1097-4172
• DOI: 10.1016/S0092-8674(00)80263-9

During the nucleolar maturation of eukaryotic ribosomal RNAs, many selected uridines are converted into pseudouridine by a thus far undefined mechanism. The nucleolus contains a large number of small RNAs (snoRNAs) that share two conserved sequence elements, box H and ACA. In this study, we demonstrate that site-specific pseudouridylation of rRNAs relies on short ribosomal signal sequences that are complementary to sequences in box H/ACA snoRNAs. Genetic depletion and reconstitution studies on yeast snR5 and snR36 snoRNAs demonstrate that box H/ACA snoRNAs function as guide RNAs in rRNA pseudouridylation. These results define a novel function for snoRNAs and further reinforce the idea that base pairing is the most common way to obtain specific substrate–“enzyme” interactions during rRNA maturation.