title: Intragenic suppressors that restore the splicing and homing activities of the protein encoded by the second intron of the Saccharomyces capensis cyt b gene.
abstract: The second (bi2) intron of the mitochondrial cyt b gene from Saccharomyces capensis encodes a bifunctional protein which acts both as a maturase, promoting intron splicing, and as a homing-endonuclease, I-ScaI, promoting intron mobility. In this work we isolated and characterized revertants from a respiratory-deficient mutant in which both functions of the protein have been lost. Intragenic revertants resulted mainly from monosubstitutions in the mutated codon and in one case from a distant second site mutation. All novel variants of the S. capensis bi2 intron-encoded protein are competent for the maturase activity but only two of them can partially complement the homing function.
authors.affiliation: Centre de Génétique Moléculaire CNRS, France.
authors.forename: K
authors.initials: K
authors.lastname: Jamoussi
authors.forename: J
authors.initials: J
authors.lastname: Lazowska
mesh_terms: D003573:Cytochrome b Group / Q000235:genetics* / Q000378:metabolism; D014644:Genetic Variation; D007438:Introns; D016296:Mutagenesis; D016297:Mutagenesis, Site-Directed; D016366:Open Reading Frames; D012313:RNA / Q000235:genetics; D012326:RNA Splicing; D012331:RNA, Fungal / Q000235:genetics; D000077278:RNA, Mitochondrial; D012194:RNA-Directed DNA Polymerase / Q000235:genetics; D012440:Saccharomyces / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins
chemical_list: D003573:Cytochrome b Group; D012331:RNA, Fungal; D000077278:RNA, Mitochondrial; D029701:Saccharomyces cerevisiae Proteins; D012313:RNA; C066564:aI2 protein, S cerevisiae; D012194:RNA-Directed DNA Polymerase