[Relation between Escherichia coli K-12 viability and mutability and the balance between DNA and protein synthesis. III. Relation between disruptions in the balance between DNA and protein synthesis and mutagenesis and viability during thymidine deprivation of thy- cells defective with respect to recB and polA genes].

The phenomenon of metabolic mutagenesis is found to be determined by stabilization of metabolic breaks in DNA chains, being linked with disbalance of intracellular synthesis of DNA and protein. The rate of metabolic mutagenesis observed in case of the DNA-protein synthesis disbalance due to thymine starvation is influenced by cell genotype. The lack of exonuclease V in recB-thy- cells decreases (reduces) the rate of metabolic mutagenesis and does not effect the viability. The lack of DNA polymerase I activity in polA-thy- cells causes a sharp increase in the metabolic mutagenesis rate and a parallel sharp drop in the survival under thymine starvation, as compared to cells with polA+thy- genotype.