Figure 1. D-loop unwinding by WRN in the absence and presence of DNA-PKcs. (A) The D-loop substrate consisted with INV, BT and BB. 5'-end of INV was radiolabeled as indicated by asterisk. WRN (3.3 nM, lanes 3-6) and increasing amounts of DNA-PKcs (0.67 nM, lane 4; 3.3 nM, lanes 5 and 7; 16.7 nM, lane 6) were incubated in standard reaction buffer prior to addition of the telomeric D-loop substrate. Reaction products were analyzed by native (B) or denaturing gel electrophoresis (C). Lanes 1 in (B) and (C): A DNA ladder marker.