Ability of base analogs to induce the SOS response: effect of a dam mutation and mismatch repair system

Summary 2-Aminopurine, 2-amino-N⁶-hydroxyadenine, 2-amino-N⁶-methoxyadenine and 2-amino-N⁶-methyl-N⁶-hydroxyadenine (but not N⁴-hydroxycytidine), strong mutagens of base analog type, may induce the SOS response in E. coli cells. This ability is greatly enhanced in dam3 mutants and abolished in dam3mutS, dam3mutH, and dam3mutL strains, thereby suggesting that the mismatch repair system is involved in the mechanism of induction.Abbreviations n²Pur 2-aminopurine - n²oh⁶Ade 2-amino-N⁶-hydroxyadenine - n²om⁶Ade 2-amino-N⁶-methyoxyadenine - n²-m⁶oh⁶Ade 2-amino-N⁶-methyl-N⁶-hydroxyadenine - oh⁴Cyd N⁴-hydroxycytidine - MC mitomycin C