2-aminopurine induced DNA repair in E. coli.

The survival of UV-irradiated lambda phages is increased when host bacteria are grown in the presence of the base analogue 2-aminopurine (2AP) before infection. This increase in survival, which we have called "2AP-reactivation" depends upon the concentration of 2AP and the time of exposure to 2AP. 2AP-reactivation can be distinguished from Weigle-reactivation in that it is not accompanied by an increase in mutagenesis, does not act on the single-stranded DNA bacteriophage phi X174, and occurs in recA and lexA bacteria. 2AP reactivation does not appear to involve known systems of recombinational repair, as it occurs in recB and recF bacteria, or excision repair, as it occurs in uvrA and uvrB bacteria. It is however dependent upon DNA polymerase I.