Figure 11.
Over-expression of Cdc25B enhances chromatin condensation induced by caffeine. Wild-type BHK21 cells were seeded at 2 × 105/35-mm dish. After 23 h of incubation at 33.5°C, cells were transfected with the indicated doses of pcD2-Cdc25B DNA. After transfection, cells were synchronized at S phase by isoleucine deprivation and HU as described in Materials and Methods. After S phase arrest, cells were given caffeine (final concentration 5 mM) and nocodazole (final concentration 0.2 μg/ ml) in the presence of HU and then incubated at 37.5°C. Every 2 h cells were fixed with cold methanol and stained with Hoechst 33342. More than 1,000 cells were scored for PCC. The frequency of cells showing PCC is shown on the vertical axis. Amount of transfected DNA: –○–, 0 μg/dish ; –•–, 1 μg/dish; –□–, 2 μg/dish; –▪–, 4 μg/dish.