Starvation for a specific amino acid induces high frequencies of rho- mutants in Saccharomyces cerevisiae.
Auxotrophic yeast cells were starved on solid media for their respective essential amino acid in the course of "adaptive mutation" experiments. Thereby, high proportions of mitochondrially respiratory deficient (rho-) mutants accumulated among the cells stressed on selective plates. Using a strain with a plus-four frameshift mutation in a chromosomal gene involved in lysine biosynthesis, we observed that many of the revertant colonies which arose late under the selective pressure were composed of mixtures of rho+ and rho- cells, indicating that they originated from founder cells containing intact as well as defective mitochondrial genomes. We show that in spite of the slower growth of rho- cells the late-appearing colonies cannot be interpreted as descending from rho- revertants present before selective plating.
Heidenreich
E
E
Department of Molecular Genetics, Institute of Tumor Biology and Cancer Research, University of Vienna, Borschkegasse 8a, A-1090 Vienna, Austria.
Wintersberger
U
U
D000222:Adaptation, Physiological; D019069:Cell Respiration / Q000502:physiology*; D002470:Cell Survival / Q000502:physiology; D016368:Frameshift Mutation; D008239:Lysine / Q000096:biosynthesis*; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D013217:Starvation
D008239:Lysine