Live cell time-lapse microscopy using a DeltaVision microscope system to analyze DNA-associated Hoechst dye (greyscale). Frames were taken every 5 min. HeLa-EM2-11 mCherry–Topo IIα cells were filmed while growing on glass-bottomed dishes after depletion of endogenous Topo IIα and release from concurrent synchrony in early S phase by double thymidine block. The presence of Doxycycline during synchrony induces expression of the exogenous mCherry–Topo IIα, resulting in normal chromosome condensation, metaphase plate formation, and normal chromosome segregation.
