Figure 3. Mild G₂ inhibition of Cdk1 induces rapid mitotic exit whole chromosome segregation. (A) Immunofluorescence of synchronized HeLa cells treated with 3 µM or without (control) RO at 6 h post-release from G₁/S. Cells were captured as they progressed through mitosis, and counter-stained with the kinetochore protein Mad2 (red) and DAPI (DNA, blue). Shown are the de-convolved maximum projections from 0.3 µm z-stacks, and the 3D surface renders of zoomed single chromosome (3 µM) and chromatid (control). All scale bars = 5 µm. (B) HeLa cells were synchronized with thymidine, released, and treated with RO at 6 h post-release. Samples were then harvested at the indicated times post-release, lysed, and analyzed by western blot with the indicated antibodies. All data shown are representative images from 3 independent experiments.