Supporting information for Zhang et al. (February 26, 2002) Proc. Natl. Acad. Sci. USA, 10.1073/pnas.042702899.
Fig. 6.
Reversibility of topo II DNA cleavage sites I and J in AML1 BV173 cells were incubated with 25 mM and 50 mM VP16 for 6 h (A) or 16 h (B). Southern blot was performed with BamHI digestion and probe A23 followed by heat treatment (H) or drug removal (I). (A) Six-hour incubation. DNA topo II cleavage fragments of 2 kb and 2.5 kb representing topo II sites I and J induced by VP16 incubation disappeared after either of the reversibility treatments, thus topo II sites I and J were reversible. (B) Sixteen-hour incubation. DNA topo II cleavage fragments of 2 kb and 2.5 kb are detected after treatment with either method for reversibility, thus topo II sites I and J are not reversible.