Cross sensitivity of mutator strains to physical and chemical mutagens.
Ten different mutator strains of Saccharomyces cerevisiae were tested for cross sensitivity to two alkylaitng agents, ethylmethanesulfonate (EMS) and methylmethanesulfonate (MMS), to determine if any of them are defective in the repair systems which normally deal with damage caused by these agents. For one of the mutators, namely mut2-1, it was shown by genetic analysis that mutator activity and MMS sensitivity are both controlled by the same gene. Two mutants, mut2-1 and mut7-1, were found to be sensitive to MMS but normal to ultraviolet and gamma-rays. Another group is represented by mut1, mut6 and mut8 which are not sensitive to any of the mutagens tested so far. Mutator strain mut2-1 was also shown not to be significantly altered for levels of UV-induced forward and reverse mutations. These observations lend support to the idea of multiple repair systems that deal with DNA damage caused by different agents and also show that mutator activity can often result from the loss of normal cellular repair systems.
D004260:DNA Repair; D005020:Ethyl Methanesulfonate / Q000494:pharmacology*; D005720:Gamma Rays; D005796:Genes; D008741:Methyl Methanesulfonate / Q000494:pharmacology*; D009154:Mutation; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D014466:Ultraviolet Rays
D005020:Ethyl Methanesulfonate; D008741:Methyl Methanesulfonate