title: Mouse U14 snRNA is a processed intron of the cognate hsc70 heat shock pre-messenger RNA.
abstract: U14 snRNA is a small nucleolar RNA species essential for eukaryotic pre-rRNA processing. We have previously shown that the mouse U14 snRNA genes are positioned within introns 5, 6, and 8 on the coding strand of the constitutively expressed cognate hsc70 heat shock gene. This genomic organization suggested the possibility that U14 snRNAs are transcribed as part of the hsc70 pre-mRNA and then excised from the intron to yield mature U14 snRNA species. To test this hypothesis directly, we have microinjected Xenopus oocytes with hsc70 pre-mRNA transcripts possessing intron 5 and the encoded U14 snRNA sequence. Processing results demonstrate that, in addition to the splicing of upstream and downstream exons, a mature 87 nt U14 snRNA is excised from the intron. Accurate excision of U14 snRNA from hsc70 intron 5 can occur in the absence of splicing. These results demonstrate a biosynthetic pathway for an snRNA species and provide a novel example of a eukaryotic pre-mRNA intron that is processed to produce a stable, biologically functional RNA species.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D006360:Heat-Shock Proteins / Q000235:genetics*; D007438:Introns; D051379:Mice; D008969:Molecular Sequence Data; D012313:RNA / Q000096:biosynthesis*; D017393:RNA Editing
chemical_list: D006360:Heat-Shock Proteins; D012313:RNA