XB-ART-48425RNA December 1, 2013; 19 (12): 1802-14.
Novel small Cajal-body-specific RNAs identified in Drosophila: probing guide RNA function.
The spliceosomal small nuclear RNAs (snRNAs) are modified post-transcriptionally by introduction of pseudouridines and 2''-O-methyl modifications, which are mediated by box H/ACA and box C/D guide RNAs, respectively. Because of their concentration in the nuclear Cajal body (CB), these guide RNAs are known as small CB-specific (sca) RNAs. In the cell, scaRNAs are associated with the WD-repeat protein WDR79. We used coimmunoprecipitation with WDR79 to recover seven new scaRNAs from Drosophila cell lysates. We demonstrated concentration of these new scaRNAs in the CB by in situ hybridization, and we verified experimentally that they can modify their putative target RNAs. Surprisingly, one of the new scaRNAs targets U6 snRNA, whose modification is generally assumed to occur in the nucleolus, not in the CB. Two other scaRNAs have dual guide functions, one for an snRNA and one for 28S rRNA. Again, the modification of 28S rRNA is assumed to take place in the nucleolus. These findings suggest that canonical scaRNAs may have functions in addition to their established role in modifying U1, U2, U4, and U5 snRNAs. We discuss the likelihood that processing by scaRNAs is not limited to the CB.
PubMed ID: 24149844
PMC ID: PMC3884663
Article link: RNA
Species referenced: Xenopus
Genes referenced: wrap53
References [+] :
Behm-Ansmant, A previously unidentified activity of yeast and mouse RNA:pseudouridine synthases 1 (Pus1p) on tRNAs. 2006, Pubmed