Figure 3. Differential effect of DNA-PKcs on WRN and BLM helicase activities. BLM (3.3 nM, lanes 3-5) and either DNA-PKcs (16.7 nM, lane 4) or RPA (16.7 nM, lanes 5 and 6) were incubated in standard reaction buffer prior to addition of the D-loop substrate. Lane 1: A DNA marker, [32P]-INV annealed with BB. Lane 7: heat-denatured D-loop substrate denoted by a filled triangle.