Send to

Choose Destination
Nucleic Acids Res. 2010 Oct;38(19):6602-9. doi: 10.1093/nar/gkq530. Epub 2010 Jun 16.

Dual roles for the Mss116 cofactor during splicing of the ai5γ group II intron.

Author information

Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.


The autocatalytic group II intron ai5γ from Saccharomyces cerevisiae self-splices under high-salt conditions in vitro, but requires the assistance of the DEAD-box protein Mss116 in vivo and under near-physiological conditions in vitro. Here, we show that Mss116 influences the folding mechanism in several ways. By comparing intron precursor RNAs with long (∼300 nt) and short (∼20 nt) exons, we observe that long exon sequences are a major obstacle for self-splicing in vitro. Kinetic analysis indicates that Mss116 not only mitigates the inhibitory effects of long exons, but also assists folding of the intron core. Moreover, a mutation in conserved Motif III that impairs unwinding activity (SAT → AAA) only affects the construct with long exons, suggesting helicase unwinding during exon unfolding, but not in intron folding. Strong parallels between Mss116 and the related protein Cyt-19 from Neurospora crassa suggest that these proteins form a subclass of DEAD-box proteins that possess a versatile repertoire of diverse activities for resolving the folding problems of large RNAs.

[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Silverchair Information Systems Icon for PubMed Central
Loading ...
Support Center