Fig. 2.

Outline of in vivo and in vitro gap-filling assays. (A) The in vivo gap-filling assay involves transformation of UV-irradiated E. coli cells with the gap-lesion plasmid and selection on plates containing kanamycin. (B) In vitro gap-filling DNA synthesis analysis was performed by using a radiolabeled gap-lesion plasmid and a purified DNA polymerase. The reaction products were restricted with MspA1I and Asp-700, fractionated by 15% PAGE–urea, followed by phosphorimaging analysis, as described in Materials and Methods. The full rectangle represents the hydrocarbon insert. The asterisk represents a radiolabeled phosphate. See text for details.