Fig. 1. Phase-contrast and fluorescent images of HeLa cells transfected with pEGFP-TPPP/p25 from time-lapse recordings. (A) Transfected cultures of HeLa cells were maintained and imaged on a microscope stage by phase-contrast and epifluorescence. A pair of cells is shown with increasing fluorescence over time. (B) Phase-contrast frames were selected from a time-lapse recording with fluorescent insets. Cells marked 1 and 2 did not show detectable fluorescence before division. Later, they became fluorescent, as shown in the image captured at 42.5 hours. Cell 2 died at 46 hours; cell 1 divided into cells 3 and 4 at 60 hours. Cells 3 and 4 were still alive after 91 hours. Time elapsed after transfection with pEGFP-TPPP/p25 is indicated in the lower left corners. Bar, 100 µm.