Fig. 6

Time-dependent plasmid linearize assay with purified plant topoII. Sc, supercoiled; L, linearized; N, nicked plasmid. a Inhibition of plant topoII activity by 5% SDS. M, molecular weight marker (step up 1 kb DNA ladder); C_1, pBS plasmid; T₀ to T_60, plasmid DNA incubated with topoII for 0 min, 10 min, 20 min, 30 min, and 60 min followed by the addition of 5% SDS to stop the reaction; C₂, EcoR1 digested plasmid. b Inhibition of plant topoII activity by etoposide. M, molecular weight marker (step up 1 kb DNA ladder); C_1, pBS plasmid; T₀ to T_60, plasmid DNA incubated with topoII for 0 min, 10 min, 20 min, 30 min, and 60 min and followed by the treatment of 5 μM etoposide; C_2, EcoR1 digested plasmid. The linear DNA is not visible well in control (C₁) but clearly visible with the increased of intensities in treatments (T₁₀ to T₆₀)