Figure 4.
End processing and end joining of a DSB bearing a 3′-phosphate on a 3′ overhang. A. Overhang 3′-phosphate substrate with partially complementary ends. Following incubation in cell extract for the indicated times and digestion with TaqαI and BstXI, unprocessed substrate is detected as a 3′-phosphate 14-mer; 3′-dephosphorylation, single-base gap filling (T) and ligation yields labeled 24-base head-to-head and 42-base head-to-tail end joining products. B. Quantitation of results from HCT116 cells. C. Quantitation of results from HeLa cells. Error bars show mean ± SEM from 3 independent experiments. Representative gels are shown in Supplemental Fig. 4.