Small Cajal body-specific RNA 18
small Cajal body-specific RNA 18 (also known as U91 or U4-8) is a type of small nuclear RNA which localises to the cajal bodies and proposed to guide the modification of RNA polymerase II transcribed spliceosomal RNAs U1, U2, U4, U5 and U12[1].
This snoRNA U91 appears to be belong to the C/D box class of snoRNAs[2]. It was identified by Darzacq[1] and is predicted to guide the 2'O-ribose methylation of U4 snRNA C8 . This C/D domain was later found associated in tandem with another C/D box domain U12-22. Both the doublet (U12-22/U4-8) and singlet (U4-8) forms of this snRNA have been purified from Hela cells [1]. The doublet form U12-22/U4-8 has been shown to localise to the nucleoplasm and is proposed to reside in the Cajal bodies whereas the U4-8 single domain appears to accumulate in the nucleolus [3]. In humans the genomic location of U12-88/U4-8 is intergenic and the purified transcript has been shown to possess a methylated guanosine cap suggesting it is independently transcribed by RNA pol II [3].
References
- ↑ 1.0 1.1 1.2 Darzacq X, Jády BE, Verheggen C, Kiss AM, Bertrand E, Kiss T (2002). "Cajal body-specific small nuclear RNAs: a novel class of 2'-O-methylation and pseudouridylation guide RNAs". EMBO J. 21 (11): 2746–56. doi:10.1093/emboj/21.11.2746. PMID 12032087.
- ↑ Galardi S, Fatica A, Bachi A, Scaloni A, Presutti C, Bozzoni I (2002). "Purified box C/D snoRNPs are able to reproduce site-specific 2'-O-methylation of target RNA in vitro". Mol. Cell. Biol. 22 (19): 6663–8. PMID 12215523.
- ↑ 3.0 3.1 Lestrade L, Weber MJ (2006). "snoRNA-LBME-db, a comprehensive database of human H/ACA and C/D box snoRNAs". Nucleic Acids Res. 34 (Database issue): D158–62. doi:10.1093/nar/gkj002. PMID 16381836.
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