Genetic effects of photoactivated psoralens during meiosis in DNA repair mutant pso3-1 of Saccharomyces cerevisiae
1994
Pothin, H.S. (Rio Grande do Sul Univ., Porto Alegre (Brazil). Inst. de Biociencias. Dept. de Fisiologia) | Silva, K.V.C.L. da | Brendel, M. | Henriques, J.A.P.
The influence of the DNA repair gene PS03 on photoactivated psoralen-induced meiotic recombination, gene conversion, reverse mutation, and on survival, was assayed in diploid strains of Saccharomyces cerevisiae homozygous for the wild-type or the pso3-1 mutant allele. Sporulation was normal in the pso3-1 diploid. Wild-type and mutant strains had the same sensitivity to photoacti- vated monofunctional psoralen (3-CPs+UVA) in meiosis-uncommitted and meiosis-committed stages. The mutant showed higher sensitivity to photoactivated bifunctional psoralen (8-MOP+UVA) during all stages of the meiotic cycle. Mutation induction by 3-CPs+UVA or 8-MOP+UVA in meiosis-committed cells revealed no significant differences between wild-type and the pso3-1 mutant. The status of the PS03 gene has no influence on the kinetics of induction of gene conversion and crossing-over after 3-CPs+UVA treatment in meiosis-committed cells: gene conversion was blocked while recombination was induced. After treatment with 8-MOP+UVA gene conversion was also blocked in both strains while crossing-over could only be observed in meiosis-committed wild-type cells.
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