[Regularities of the induction of point mutation in the yeast Saccharomyces cerevisiae after exposure to gamma-radiation].
A tester system consisting of six isogenic strains was used to study the regularities of the induction of point mutations in the yeast Saccharomyces cerevisiae after exposure to gamma-radiation. This system allowed the identification of all six possible substitutions in the Cys-22 codon of the CYC1 gene encoding iso-1-cytochrome c. The dose dependence of the frequency of these six base-pair substitutions was shown to be linear-quadratic. The pattern of base substitutions did not depend on the doses of gamma-irradiation used (from 125 to 1000 Gy) and predominantly included GC-->AT transitions and AT-->TA transversions. The possible mechanisms of gamma-ray mutagenesis leading to a nonlinear dose dependence were considered, and the spectra of mutations obtained for different yeast genes and for Escherichia coli were compared.
Liubimova
K A
KA
Department of Radiation and Radiological Research, Joint Institute for Nuclear Research, Moscow oblast, Dubna, Russia.
Anikin
S A
SA
Koltovaia
N A
NA
Krasavin
E A
EA
D003062:Codon; D003545:Cysteine / Q000737:chemistry; D003574:Cytochrome c Group / Q000235:genetics; D045304:Cytochromes c; D004926:Escherichia coli / Q000235:genetics; D005720:Gamma Rays; D017354:Point Mutation; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000528:radiation effects; D029701:Saccharomyces cerevisiae Proteins; D013045:Species Specificity
C014059:CYC1 protein, S cerevisiae; D003062:Codon; D003574:Cytochrome c Group; D029701:Saccharomyces cerevisiae Proteins; D045304:Cytochromes c; D003545:Cysteine