Reduction of dNTP levels enhances DNA replication fidelity in vivo
Résumé
ATP is the most important energy source for the maintenance and growth of living cells. Here we report that the impairment of the aerobic respiratory chain by inactivation of the ndh gene, or the inhibition of glycolysis with arsenate, both of which reduce intracellular ATP, result in a significant decrease in spontaneous mutagenesis in Escherichia coli. The genetic analyses and mutation spectra in the ndh strain revealed that the decrease in spontaneous mutagenesis resulted from an enhanced accuracy of the replicative DNA polymerase. Quantification of the dNTP content in the ndh mutant cells and in the arsenate-treated cells showed reduction of the dNTP pool, which could explain the observed broad antimutator effects. In conclusion, our work indicates that the cellular energy supply could affect spontaneous mutation rates and that a reduction of the dNTP levels can be antimutagenic.