An mRNA maturase is encoded by the first intron of the mitochondrial gene for the subunit I of cytochrome oxidase in S. cerevisiae.
We have localized ten oxi3- mutations in the first, al1, intron of the coxl gene. All are splicing deficient, being unable to excise the intron. Complementation experiments disclose several domains in the intron al1: the 5'-proximal and 3'-proximal domains harbor cis-dominant mutations, while trans-recessive ones are located in the intron's open reading frame. Comprehensive analyses of allele-specific polypeptides accumulating in mutants show that they result from the translation of the intron's ORF. We conclude that a specific mRNA maturase involved in splicing of oxidase mRNA is encoded by the intron al1 in a manner similar to the cytochrome b mRNA maturase.
D002874:Chromosome Mapping; D004272:DNA, Mitochondrial / Q000235:genetics*; D003576:Electron Transport Complex IV / Q000235:genetics*; D004722:Endoribonucleases; D005796:Genes; D046911:Macromolecular Substances; D008970:Molecular Weight; D009713:Nucleotidyltransferases / Q000235:genetics; D014176:Protein Biosynthesis; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D014158:Transcription, Genetic
D004272:DNA, Mitochondrial; D046911:Macromolecular Substances; D003576:Electron Transport Complex IV; D009713:Nucleotidyltransferases; C034038:mRNA maturase; D004722:Endoribonucleases