Proofreading-defective DNA polymerase II increases adaptive mutation in Escherichia coli.

Dysfunctional proofreading in the Escherichia coli DNA polymerase III core.

The epsilon-subunit contains the catalytic site for the 3'-->5' proofreading exonuclease that functions in the DNA pol III (DNA polymerase III) core to edit nucleotides misinserted by the alpha-subunit DNA pol. A novel mutagenesis strategy was used to identify 23 dnaQ alleles that exhibit a mutator phenotype in vivo. Fourteen of the epsilon mutants were purified, and these proteins exhibited 3'...

Adaptive mutation in Escherichia coli.

In 1988 John Cairns, Julie Overbaugh, and Stephan Miller published a paper entitled “The origin of mutants,” in which they suggested that bacteria could choose which mutations to make (11). Shortly thereafter, Cairns and I began collaborating on a National Science Foundation-funded project to investigate the genetic basis of what was popularly called “directed mutation” (although at the time we...

The Subunit of Escherichia coli DNA Polymerase III: a Role in Stabilizing the ε Proofreading Subunit

The function of the subunit of Escherichia coli DNA polymerase III holoenzyme is not well established. is a tightly bound component of the DNA polymerase III core, which contains the subunit (polymerase), the subunit (3 35 exonuclease), and the subunit, in the linear order . Previous studies have shown that the subunit is not essential, as strains carrying a deletion of the holE gene (which enc...

Rebuttal: adaptive mutation in Escherichia coli (Foster).

If mutations arose in nongrowing cells, as proposed in Foster’s paper (1), then stress-induced mutagenesis would seem inescapable. The plated population certainly grows very little. However, no evidence is provided that reversion occurs in this population and no effort is made to counter evidence to the contrary (see below)—that mutations actually arise in cells growing under selection within d...

production of thermus aquaticus dna polymerase in escherichia coli