1. Effects of recombinant human HPSE on Topo I activity in 231BR3 nucleoli.
Effects of recombinant human HPSE on Topo I activity in 231BR3 nucleoli. Representative experiments in which (A) recombinant human active HPSE (rhaHPSE) and (B) inactive HPSE (rhiHPSE) were added to nucleoli isolated from 231BR3 cells (no EGF treatment) at indicated concentrations (0, 10, and 100 ng/mL), following incubation for 30 min at 37°C with supercoiled DNA (100 ng) provided by the TopoGen kit. Topo I activity was examined by 1% agarose gel electrophoresis with ethidium bromide, was visualized using the UV transilluminator, and was determined by DNA status. Relaxed DNA (Rel) indicates Topo I activity, whereas supercoiled DNA (Sc) indicates a lack of Topo I activity. Rel and Sc DNA were used as positive/negative marker controls, respectively. Lower panels were prepared upon densitometric analyses from three independent experiments. Columns, mean measurements from three independent experiments; bars, SD. *, P < 0.01; **, P <
Lixin Zhang et al. Mol Cancer Res 2010;8:
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