FIG. 6.

Tax activates cells to enter into S phase but arrests them at G₂/M phase. PA18G-BHK-21 cells transduced with pBabe-puro (A) or pBabe-Tax (B) were placed under puromycin selection for 10 days and harvested for FACS analyses. Three million transduced cells were fixed in ethanol, stained with PI, and sorted by FACS. The DNA contents are as indicated. The inset in each panel shows the integrated total DNA content as reflected by total fluorescence signal (horizontal axis) and nuclear size as reflected by peak DNA content (vertical axis) of the total cell population analyzed. The cell number versus DNA content (regions R1, R2, and R3) was plotted. Mean values of the percentage of cells in different stages of cell cycle in R1 are indicated. Many pBabe-Tax-transduced cells were found to have a DNA content of more than 4N but with peak fluorescence of a single nucleus, consistent with the microscopic observation that they are multinucleated.