Product of Saccharomyces cerevisiae nuclear gene PET494 activates translation of a specific mitochondrial mRNA.
The product of Saccharomyces cerevisiae nuclear gene PET494 is known to be required for a posttranscriptional step in the accumulation of one mitochondrial gene product, subunit III of cytochrome c oxidase (coxIII). Here we show that the PET494 protein probably acts in mitochondria by demonstrating that both a PET494-beta-galactosidase fusion protein and unmodified PET494 are specifically associated with mitochondria. To define the PET494 site of action, we isolated mutations that suppress a pet494 deletion. These mutations were rearrangements of the mitochondrial gene oxi2 that encodes coxIII. The suppressor oxi2 genes had acquired the 5'-flanking sequences of other mitochondrial genes and gave rise to oxi2 transcripts carrying the 5'-untranslated leaders of their mRNAs. These results demonstrate that in wild-type cells PET494 specifically promotes coxIII translation, probably by interacting with the 5'-untranslated leader of the oxi2 mRNA.
D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism*; D005796:Genes; D005800:Genes, Fungal; D009154:Mutation; D010957:Plasmids; D014176:Protein Biosynthesis; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000235:genetics*; D000077278:RNA, Mitochondrial; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D001616:beta-Galactosidase / Q000235:genetics
D012333:RNA, Messenger; D000077278:RNA, Mitochondrial; C029305:mitochondrial messenger RNA; D001616:beta-Galactosidase