FIGURE 3.
Cell cycle progression in CAGE-overexpressing HeLa cells. A, tetracycline-inducible CAGE transfectant clones were synchronized by double thymidine for G1/S block. After treatment with or without doxycycline for 2 h, synchronized cells were released in complete medium supplemented with or without doxycycline for the indicated time periods. After cells were labeled with propidium iodide, DNA content was analyzed by flow cytometry. Shown are representative histograms and the means of cell cycle phase distribution from three independent experiments. B, cells synchronized by double thymidine block were released in the absence or presence of doxycycline (dox) for the indicated time periods. After BrdUrd treatment, cells were stained with fluorescein isothiocyanate (FITC)-conjugated anti-BrdUrd antibody and viewed under a fluorescence microscope. Shown are representative images and the means ± S.D. of BrdUrd-positive cell counts in triplicate cultures.