title: The splicing of yeast mitochondrial group I and group II introns requires a DEAD-box protein with RNA chaperone function.
abstract: Group I and II introns self-splice in vitro, but require proteins for efficient splicing in vivo, to stabilize the catalytically active RNA structure. Recent studies showed that the splicing of some Neurospora crassa mitochondrial group I introns additionally requires a DEAD-box protein, CYT-19, which acts as an RNA chaperone to resolve nonnative structures formed during RNA folding. Here we show that, in Saccharomyces cerevisiae mitochondria, a related DEAD-box protein, Mss116p, is required for the efficient splicing of all group I and II introns, some RNA end-processing reactions, and translation of a subset of mRNAs, and that all these defects can be partially or completely suppressed by the expression of CYT-19. Results for the aI2 group II intron indicate that Mss116p is needed after binding the intron-encoded maturase, likely for the disruption of stable but inactive RNA structures. Our results suggest that both group I and II introns are prone to kinetic traps in RNA folding in vivo and that the splicing of both types of introns may require DEAD-box proteins that function as RNA chaperones.
authors.affiliation: Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA.
authors.forename: Hon-Ren
authors.initials: HR
authors.lastname: Huang
authors.forename: Claire E
authors.initials: CE
authors.lastname: Rowe
authors.forename: Sabine
authors.initials: S
authors.lastname: Mohr
authors.forename: Yue
authors.initials: Y
authors.lastname: Jiang
authors.forename: Alan M
authors.initials: AM
authors.lastname: Lambowitz
authors.forename: Philip S
authors.initials: PS
authors.lastname: Perlman
mesh_terms: D020816:Amino Acid Motifs / Q000235:genetics / Q000502:physiology; D053487:DEAD-box RNA Helicases; D007438:Introns / Q000235:genetics* / Q000502:physiology; D008928:Mitochondria / Q000235:genetics* / Q000378:metabolism; D018832:Molecular Chaperones / Q000378:metabolism*; D009154:Mutation; D014176:Protein Biosynthesis / Q000502:physiology; D012313:RNA / Q000096:biosynthesis*; D020365:RNA Helicases / Q000235:genetics / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional / Q000235:genetics / Q000502:physiology*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins
chemical_list: D018832:Molecular Chaperones; D029701:Saccharomyces cerevisiae Proteins; D012313:RNA; C058150:MSS116 protein, S cerevisiae; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases