title: The RNA world of the nucleolus: two major families of small RNAs defined by different box elements with related functions.
abstract: We have discovered that all known yeast and vertebrate small nucleolar RNAs (snoRNAs), except for the MRP/7-2 RNA, fall into two major classes. One class is defined by conserved boxes C and D and the other by a novel element: a consensus ACA triplet positioned 3 nt before the 3' end of the RNA. A role for the ACA box is snoRNA stability has been established by mutational analysis of a yeast ACA snoRNA (snR 11). Full function of the box depends on the integrity of an adjacent upstream stem. All members of the yeast ACA family are associated with the GAR1 protein. Binding of this or another common small nucleolar ribonucleoprotein particle protein is predicted to be a critical entry point to snoRNA posttranscriptional life, including precise formation of the snoRNA 3' end.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst 01003, USA.
authors.forename: A G
authors.initials: AG
authors.lastname: Balakin
authors.forename: L
authors.initials: L
authors.lastname: Smith
authors.forename: M J
authors.initials: MJ
authors.lastname: Fournier
mesh_terms: D000818:Animals; D001483:Base Sequence; D002466:Cell Nucleolus / Q000235:genetics*; D003001:Cloning, Molecular; D016384:Consensus Sequence / Q000235:genetics; D017124:Conserved Sequence / Q000235:genetics*; D004252:DNA Mutational Analysis; D004926:Escherichia coli; D005656:Fungal Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D009690:Nucleic Acid Conformation; D012342:RNA, Small Nuclear / Q000737:chemistry / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D012261:Ribonucleoproteins; D020718:Ribonucleoproteins, Small Nucleolar; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D017423:Sequence Analysis, RNA; D014714:Vertebrates / Q000235:genetics
chemical_list: D005656:Fungal Proteins; D009687:Nuclear Proteins; D012342:RNA, Small Nuclear; D012261:Ribonucleoproteins; D020718:Ribonucleoproteins, Small Nucleolar; D029701:Saccharomyces cerevisiae Proteins; C073180:GAR1 protein, S cerevisiae