Low Temperature and Chloramphenicol Induction of Respiratory Deficiency in a Cold-Sensitive Mutant of Saccharomyces cerevisiae

A cold-sensitive mutant of a haploid strain ofSaccharomyces cerevisiae has been isolated by selection for impaired growth at 18° on nonfermentable carbon sources. Growth of the mutant on glucose or galactose at either 28 or 18° is similar to that of the parental strain. The cold-sensitive strain is highly mutable to a cytoplasmic petite when grown at 18°, or when grown at 28° in the presence of 4 mg/ml of chloramphenicol. Cold sensitivity is not observed in the conversion of promitochondria to mitochondria. We conclude that mitochondrial protein synthesis is required for maintaining the stability of the mitochondrial genome.