Biogenesis of mitochondria: DNA sequence analysis of mit- mutations in the mitochondrial oli2 gene coding for mitochondrial ATPase subunit 6 in Saccharomyces cerevisiae.
A series of yeast mitochondrial mit- mutants with defects in the oli2 gene, coding for subunit 6 of the mitochondrial ATPase complex, has been analyzed at the DNA sequence level. Fifteen of sixteen primary mit- mutants were shown to contain frameshift or nonsense mutations predicting truncated subunit 6 polypeptides, in various strains ranging from about 20% to 95% of the wild-type length of 259 amino acids. In only one strain could the defect in subunit 6 function be assigned to amino acid substitution in an otherwise full-length subunit 6. Many mutants carried multiple base substitutions or insertions/deletions, presumably arising from the manganese chloride mutagenesis treatment. Revertants from three of the mit- mutants were analyzed: all contained full-length subunit 6 proteins with one or more amino acid substitutions. The preponderance of truncated proteins as opposed to substituted full-length proteins in oli2 mit- mutants is suggested to reflect the ability of subunit 6 to accommodate amino acid substitutions at many locations, with little or no change in its functional properties in the membrane FO-sector of the ATPase complex.
D000251:Adenosine Triphosphatases / Q000235:genetics*; D000595:Amino Acid Sequence; D001483:Base Sequence; D003062:Codon; D004271:DNA, Fungal / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics*; D005796:Genes; D005800:Genes, Fungal; D046911:Macromolecular Substances; D008928:Mitochondria / Q000378:metabolism*; D009154:Mutation; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*
D003062:Codon; D004271:DNA, Fungal; D004272:DNA, Mitochondrial; D046911:Macromolecular Substances; D000251:Adenosine Triphosphatases