Mutational consequences of dNTP pool imbalances in E. coli

► dCTPase-deficient mutants (dcd) of E. coli are mutators. ► dcd and nucleoside diphosphate kinase (ndk) mutants possess defined dNTP changes. ► In vivo dNTP changes correlate with the types of in vivo DNA replication errors. ► In vivo dNTP levels are kept low to facilitate proofreading of replication errors.