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Analysis of bleomycin‐induced mutagenic functions related to the PSO4 (= XS9) gene of saccharomyces cerevisiae
Author(s) -
Severgnini A.,
Lillo O.,
Nunes E.,
Brockman H. E.
Publication year - 1991
Publication title -
environmental and molecular mutagenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1
H-Index - 87
eISSN - 1098-2280
pISSN - 0893-6692
DOI - 10.1002/em.2850180204
Subject(s) - mutant , saccharomyces cerevisiae , biology , mutation , genetics , gene , mutagen , bleomycin , mutagenesis , dna repair , microbiology and biotechnology , dna , chemotherapy
In the present work we analyse some properties of the pso4‐1 (= xs9) mutant of the yeast Sac‐charomyces cerevisiae, which is blocked in both reverse mutation and recombination. We have applied the “apparent survival test” as a method to characterize putative inducible errorprone repair activities related to the PSO4 gene. As the mutagenic agent we have used bleomycin, which is an antitumour radiomimetic antibiotic. Survival, reverse mutation yield, and reverse mutation frequency were determined as a function of bleomycin concentrations (1‐60 μg/ml) in the logarithmic phase of growth. It is shown that the PSO4 gene product is poorly involved in bleomycin sensitivity and that reverse mutation induced by this mutagen is dramatically reduced in the pso4‐1 lys2 mutant strain, as compared with the isogenic SC7K ( lys2 ) strain. M(x) functions exhibit linear‐quadratic courses for both the SC7K ( lys2 ) and the pso4‐1 lys2 strains. The apparent survival functions display “humps” in both strains, corresponding to the resistant components of the survival functions. These facts suggest that the mutagenicity of bleomycin depends on at least one inducible error‐prone repair pathway and that the PSO4 gene product could act as a mutation triggering factor.