Figure 2.

Comparison of the rates of post-UV DNA synthesis in wild-type, ΔpolB, and ΔumuDC strains. Experiments were performed as described in Materials and Methods. In the lower portion, the rate of ³H thymidine incorporation (both before and after UV) is plotted on a logarithmic scale as a percentage of the rate of incorporation at the time of UV irradiation. In the upper portion, the linear regressions are determined from an average of A₄₅₀ values for the two strains in each plot. (A) ○, AB1157 (polB⁺umuDC⁺); ■, SR1157U (ΔumuDC). (B) ○, AB1157 (polB⁺umuDC⁺); ▾, STL1336 (ΔpolB). The experiment from which the data were plotted was repeated six times and is reproducible. The delay before resumption of replication in the ΔpolB strain, shown in B, is occurring between 50 and 60 min post-irradiation.