The splicing of yeast mitochondrial group I and group II introns requires a DEAD-box protein with RNA chaperone function

• DOI: 10.1073/pnas.0407896101
• Publication Date: 2004-12-24T02:32:21Z
• Authors: Hon-Ren Huang; Claire E. Rowe; Sabine Mohr; Yue Jiang; Alan M. Lambowitz; Philip S. Perlman
• Keywords: 0303 health sciences; Saccharomyces cerevisiae Proteins; Amino Acid Motifs; Saccharomyces cerevisiae; Introns; Mitochondria; DEAD-box RNA Helicases; 03 medical and health sciences; Protein Biosynthesis; Mutation; RNA; RNA Processing, Post-Transcriptional; RNA Helicases; Molecular Chaperones

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.