title: An RNA-dependent ATPase associated with U2/U6 snRNAs in pre-mRNA splicing.
abstract: The hydrolysis of ATP by a group of RNA-dependent ATPases (DEAD/H proteins) is required for spliceosome assembly, but not for the subsequent transesterification reactions. Little is known about the function of these ATPases in relation to the RNA conformational changes that occur in formation of active structures, in which U2/U6 small nuclear RNA (snRNA) interactions are essential for splicing to take place. Using a synthetic lethal genetic screen, we have isolated four yeast splicing factors involved in U2/U6 snRNA interactions (D.X. et al., manuscript in preparation). The RNA-dependent ATPase activity associated with one such factor, the Slt22 protein, is stimulated preferentially by annealed U2/U6 snRNAs. Both mutant slt22-1 and U2 snRNA cause a reduction in stimulation. The slt22-1 mutation blocks splicing at or before the first step, resulting in the accumulation of an unusual complex which lacks U5 snRNA. Our results indicate that the U2/U6 snRNA interactions facilitated by Slt22 are also involved in the interaction of U5 snRNA with the spliceosome.
authors.affiliation: Department of Genetics, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: D
authors.initials: D
authors.lastname: Xu
authors.forename: S
authors.initials: S
authors.lastname: Nouraini
authors.forename: D
authors.initials: D
authors.lastname: Field
authors.forename: S J
authors.initials: SJ
authors.lastname: Tang
authors.forename: J D
authors.initials: JD
authors.lastname: Friesen
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D001483:Base Sequence; D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D012322:RNA Precursors / Q000378:metabolism*; D012326:RNA Splicing; D012331:RNA, Fungal / Q000378:metabolism; D012342:RNA, Small Nuclear / Q000737:chemistry / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D017381:Spliceosomes / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D012322:RNA Precursors; D012331:RNA, Fungal; D012342:RNA, Small Nuclear; D000251:Adenosine Triphosphatases; C027900:RNA-dependent ATPase