title: Single base substitution in an intron of oxidase gene compensates splicing defects of the cytochrome b gene.
abstract: An extragenic suppressor mutation, mim2-1, which compensates yeast mitochondrial mutants deficient in splicing of the cytochrome b gene, has been mapped and sequenced. The mutation is due to a single G leads to A transition in the long open reading frame of the fourth intron of the oxidase subunit one gene. It causes the replacement of a glutamic codon by a lysine codon and the expression of a novel mRNA maturase active in splicing. Evolution and regulatory connections between homologous introns of nonhomologous genes are discussed.
mesh_terms: D001483:Base Sequence; D005075:Biological Evolution; D003573:Cytochrome b Group; D003580:Cytochromes / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics*; D003576:Electron Transport Complex IV / Q000235:genetics*; D004720:Endonucleases / Q000235:genetics*; D004722:Endoribonucleases; D005796:Genes; D009154:Mutation; D012326:RNA Splicing; D012260:Ribonucleases / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics; D013489:Suppression, Genetic
chemical_list: D003573:Cytochrome b Group; D003580:Cytochromes; D004272:DNA, Mitochondrial; D003576:Electron Transport Complex IV; D004720:Endonucleases; D004722:Endoribonucleases; D012260:Ribonucleases