The involvement of the RAD6 gene in starvation-induced reverse mutation in Saccharomyces cerevisiae.
The accumulation of Ade+ revertants during adenine starvation and Trp+ revertants during tryptophan starvation in haploid polyauxotrophic strains of Saccharomyces cerevisiae occurs in a time-dependent manner. Accumulation of revertants is enhanced in Rad6- strains, suggesting that starvation-induced reversion is influenced by some of the RAD6 gene functions. The higher frequency of adaptive reversions in Rad6- strains is somewhat influenced by, but does not totally depend on, the genetic background. Therefore, the RAD6 gene product is involved in maintaining a low level not only of spontaneous mutation but also of starvation-induced reversion. The starvation-induced Ade+ and Trp+ reversions both appear to be adaptive. The analysis of growth characteristics and the genotype of revertants shows a difference between early and late-appearing revertants. These results support the hypothesis that the adaptivity of starvation-induced reversion is based on the selective fixation of random mutations, and particularly on transcription-enhanced repair and/or mutagenesis processes.
Storchová
Z
Z
Department of Genetics and Microbiology, Faculty of Natural Sciences, Charles University, Praha, Czech Republic. zuzana@prfdec.natur.cuni.cz
Rojas Gil
A P
AP
Janderová
B
B
Vondrejs
V
V
D000222:Adaptation, Physiological / Q000235:genetics; D000225:Adenine / Q000378:metabolism; D005800:Genes, Fungal / Q000502:physiology*; D008025:Ligases / Q000235:genetics* / Q000502:physiology; D009154:Mutation; D010641:Phenotype; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000254:growth & development; D029701:Saccharomyces cerevisiae Proteins; D014364:Tryptophan / Q000378:metabolism; D044763:Ubiquitin-Conjugating Enzymes
D029701:Saccharomyces cerevisiae Proteins; D014364:Tryptophan; C471606:RAD6 protein, S cerevisiae; D044763:Ubiquitin-Conjugating Enzymes; D008025:Ligases; D000225:Adenine