The nuclear SUV3-1 mutation affects a variety of post-transcriptional processes in yeast mitochondria.
The SUV3-1 mutation was isolated earlier as a suppressor of a deletion of a conserved RNA processing site (dodecamer) near the 3' end of the var1 gene. Previous studies indicate that the suppressor enhances translation of mutant var1 messages; unexpectedly, it also causes over-accumulation of excised intron RNA of the large rRNA gene intron and blocks cleavage at the dodecamer site within that intron. In this study most mitochondrial genes in SUV3-1 and suv3 nuclear contexts are surveyed for changes in levels of mRNA, for interference with dodecamer cleavage and splicing and for levels of excised intron RNAs. SUV3-1 has little or no effect on the size or abundance of unspliced RNAs tested. It results, however, in a marked increase in the abundance of seven of eight excised group I intron RNAs tested, most of which are not detectable in wild-type (suv3) strains. The suppressor lowers levels of the cob and coxl mRNAs about 2-5 and 20-fold, respectively. The effect on coxl mRNA results from a decrease in the splicing of its intron 5 beta. Despite the reduction in these mRNA levels, the amounts of coxl and cyt b polypeptides were close to wild-type levels in SUV3-1 cells. These data show that the suv3 gene plays a prominent role in post-transcriptional and translation events in yeast mitochondria.
Conrad-Webb
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Department of Molecular Genetics, Ohio State University, Columbus 43210-1292.
Perlman
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PS
Zhu
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Butow
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RA
D002467:Cell Nucleus / Q000378:metabolism*; D003573:Cytochrome b Group / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D003576:Electron Transport Complex IV / Q000235:genetics; D005800:Genes, Fungal; D007438:Introns; D008928:Mitochondria / Q000378:metabolism*; D009154:Mutation; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000235:genetics; D012335:RNA, Ribosomal / Q000235:genetics; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism
D003573:Cytochrome b Group; D004275:DNA, Ribosomal; D012333:RNA, Messenger; D012335:RNA, Ribosomal; D003576:Electron Transport Complex IV