Top1-mediated DNA cleavage induced by compounds 24, 26,
28, 27, 29, 2 and
18. Lane 1: DNA alone; lane 2: Top1 alone; lane 3:
I, 1 RM:; lane 4: Indenoisoquinoline 55, 1 RM;
lane 5–25: 24, 26, 28,
27, 29, 2 and 18 at 1,
10 and 100 RM respectively from left to right. Numbers and arrows on the left
indicate arbitrary cleavage site positions.