The Box C/D motif directs snoRNA 5′-cap hypermethylation
AUTOR(ES)
Speckmann, Wayne A.
FONTE
Oxford University Press
RESUMO
The 5′-cap structure of most spliceosomal small nuclear RNAs (snRNAs) and certain small nucleolar RNAs (snoRNAs) undergoes hypermethylation from a 7-methylguanosine to a 2,2,7-trimethylguanosine structure. 5′-Cap hypermethylation of snRNAs is dependent upon a conserved sequence element known as the Sm site common to most snRNAs. Here we have performed a mutational analysis of U3 and U14 to determine the cis-acting sequences required for 5′-cap hypermethylation of Box C/D snoRNAs. We have found that both the conserved sequence elements Box C (termed C′ in U3) and Box D are necessary for cap hypermethylation. Furthermore, the terminal stem structure that is formed by sequences that flank Box C (C′ in U3) and Box D is also required. However, mutation of other conserved sequences has no effect on hypermethylation of the cap. Finally, the analysis of fragments of U3 and U14 RNAs indicates that the Box C/D motif, including Box C (C′ in U3), Box D and the terminal stem, is capable of directing cap hypermethylation. Thus, the Box C/D motif, which is important for snoRNA processing, stability, nuclear retention, protein binding, nucleolar localization and function, is also necessary and sufficient for cap hypermethylation of these RNAs.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=113864Documentos Relacionados
- Coupling between snoRNP assembly and 3′ processing controls box C/D snoRNA biosynthesis in yeast
- Conserved Stem II of the Box C/D Motif Is Essential for Nucleolar Localization and Is Required, Along with the 15.5K Protein, for the Hierarchical Assembly of the Box C/D snoRNP
- 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
- Purified Box C/D snoRNPs Are Able To Reproduce Site-Specific 2′-O-Methylation of Target RNA In Vitro
- Circular box C/D RNAs in Pyrococcus furiosus