Figure 7.

MEK1 regulates mitotic entry via Myt1. (A) HeLa cells were transfected with control or MEK1 specific siRNA oligos and after 48 h the level of MEK1 depletion was evaluated by western blotting the total cell lysates. Western blotting with an anti-β-actin antibody was used as a loading control. (B) Quantification of the MEK1 levels upon siRNA transfection. (C and D) The mitotic index was determined at the indicated times after thymidine release for control and MEK1 siRNA transfected cells (C) and DMSO and PD treated cells (D). (E) The percentage of cells in late G2 in the total number of cells in late G2 and all stages of mitosis was determined at the indicated times after thymidine release for DMSO and PD treated cells. For each time point, 400 cells were counted (mean±s.d., n=3). (F and G) To test the effect of Myt1 knockdown on the delay in mitotic entry induced by MEK1 downregulation, the mitotic index was calculated at the indicated times after thymidine release for control and Myt1 siRNA transfected cells, in cells transfected with MEK1 siRNA (F) or treated with PD (G). (H) The percentage of cells in late G2 in the total number of cells in late G2 and all stages of mitosis was determined at the indicated times after thymidine release for control and Myt1 siRNA transfected cells, in cells treated with PD. For each time point, 400 cells were counted (mean±s.d., n=3).

Source data for this figure is available on the online supplementary information page.

Source Data for Figure 7A ^{(63.3KB, pdf)}