In vivo, large RNAs rely on proteins to fold to their native conformation. In the case of the S. cerevisiae group II intron ai5 gamma, the DEAD-box protein Mss116 has been shown to promote the formation of the catalytically active structure. However, it is a matter of debate whether it does this by stabilizing on-pathway intermediates or by disrupting misfolded structures. Here we present the available experimental evidence to distinguish between those mechanisms and discuss the possible interpretations.
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http://dx.doi.org/10.1093/nass/nrn034 | DOI Listing |
Biochem Cell Biol
October 2024
Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.
Group I and II introns are large catalytic RNAs (ribozymes) that are frequently encountered in fungal mitochondrial genomes. The discovery of respiratory mutants linked to intron splicing defects demonstrated that for the efficient removal of organellar introns there appears to be a requirement of protein splicing factors. These splicing factors can be intron-encoded proteins with maturase activities that usually promote the splicing of the introns that encode them (-acting) and/or nuclear-encoded factors that can promote the splicing of a range of different introns (-acting).
View Article and Find Full Text PDFRNA Biol
July 2011
Department of Biochemistry and Cell Biology, University of Vienna, Vienna, Austria.
In yeast mitochondria the DEAD-box helicase Mss116p is essential for respiratory growth by acting as group I and group II intron splicing factor. Here we provide the first structure-based insights into how Mss116p assists RNA folding in vivo. Employing an in vivo chemical probing technique, we mapped the structure of the ai5γ group II intron in different genetic backgrounds to characterize its intracellular fold.
View Article and Find Full Text PDFJ Mol Biol
April 2010
Howard Hughes Medical Institute, Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
Multiple studies hypothesize that DEAD-box proteins facilitate folding of the ai5gamma group II intron. However, these conclusions are generally inferred from splicing kinetics, and not from direct monitoring of DEAD-box protein-facilitated folding of the intron. Using native gel electrophoresis and dimethyl sulfate structural probing, we monitored Mss-116-facilitated folding of ai5gamma intron ribozymes and a catalytically active self-splicing RNA containing full-length intron and short exons.
View Article and Find Full Text PDFNucleic Acids Symp Ser (Oxf)
November 2010
Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA.
RNA
October 2008
Howard Hughes Medical Institute, University of Colorado, Department of Chemistry and Biochemistry, Boulder, Colorado 80309-0215, USA.
In the current era of massive discoveries of noncoding RNAs within genomes, being able to infer a function from a nucleotide sequence is of paramount interest. Although studies of individual group I introns have identified self-splicing and nonself-splicing examples, there is no overall understanding of the prevalence of self-splicing or the factors that determine it among the >2300 group I introns sequenced to date. Here, the self-splicing activities of 12 group I introns from various organisms were assayed under six reaction conditions that had been shown previously to promote RNA catalysis for different RNAs.
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