Figure 4.
Inhibition of cyclin B proteolysis in OA-treated extracts is overcome by Ca2+ treatment. The electrophoretic mobility shift of 35S-labeled Cdc25 and the stability of 35S-labeled cyclin B were analyzed in extracts entering mitosis, induced by addition of Δ90. The extracts contained 1 μM OA and were either treated with 0.5 mM CaCl2 after 20 min (right panel; indicated by arrows) or not (left panel). Samples were taken at the indicated time points and analyzed by SDS-PAGE and phosphorimaging.