Genetic effects of photoactivated psoralens during meiosis in DNA repair mutant pso3-1 of Saccharomyces cerevisiae.
The influence of the DNA repair gene PSO3 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 photoactivated 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 PSO3 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.
Pothin
H S
HS
Departamento de Fisiologia, UFRGS, Porto Alegre, RS, Brasil.
da Silva
K V
KV
Brendel
M
M
Henriques
J A
JA
D004260:DNA Repair / Q000235:genetics; D011564:Furocoumarins / Q000494:pharmacology* / Q000528:radiation effects; D005785:Gene Conversion; D005800:Genes, Fungal / Q000187:drug effects*; D008540:Meiosis / Q000187:drug effects / Q000235:genetics; D016296:Mutagenesis; D009154:Mutation; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D013172:Spores, Fungal / Q000187:drug effects / Q000235:genetics; D014466:Ultraviolet Rays
D011564:Furocoumarins