Mitochondrial splicing requires a protein from a novel helicase family.
Proteins involved in mitochondrial splicing but encoded by nuclear genes have been characterized in Saccharomyces and Neurospora. The role in splicing of these proteins is largely unknown. Here we report that mutations in the nuclear gene MSS116 directly affect the splicing of several introns of the cytochrome b (cob) and cytochrome c oxidase subunit I (cox1) primary transcripts. This implies that the MSS116 protein (pMSS116) is an important component of the mitochondrial splicing machinery. The sequence of the cloned MSS116 gene shows that its protein product is homologous to the translation eIF-4A factor and the human nuclear protein p68. We show further that these proteins share several conserved amino-acid blocks with DNA helicases and related proteins. This suggests that pMSS116 has an RNA helicase activity. RNA helicases may be involved in many different processes including translation and splicing.
Séraphin
B
B
Institut Curie-Biologie, Orsay, France.
Simon
M
M
Boulet
A
A
Faye
G
G
D000595:Amino Acid Sequence; D001483:Base Sequence; D003573:Cytochrome b Group / Q000235:genetics; D053487:DEAD-box RNA Helicases; D004272:DNA, Mitochondrial; D003576:Electron Transport Complex IV / Q000235:genetics; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D010448:Peptide Initiation Factors / Q000235:genetics; D020365:RNA Helicases; D012316:RNA Nucleotidyltransferases / Q000378:metabolism*; D012326:RNA Splicing; D012440:Saccharomyces / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins
D003573:Cytochrome b Group; D004272:DNA, Mitochondrial; D010448:Peptide Initiation Factors; D029701:Saccharomyces cerevisiae Proteins; D003576:Electron Transport Complex IV; D012316:RNA Nucleotidyltransferases; C058150:MSS116 protein, S cerevisiae; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases