FIG. 6.

E2F-1 overexpression decreases the duration of the G1 cell cycle phase in proliferating cells. Exponentially growing control (○) and Linker Neo CMV E2F-infected (•) cells were treated with nocodazole at 0 h. At the indicated times thereafter, cells were trypsinized, fixed, stained, and analyzed for DNA content by flow cytometry. The percentages of G1 phase cells as percentages of total cells were obtained from computer analysis of the DNA histograms and plotted against the time after nocodazole addition that the cell sample was taken. Regression lines were drawn through the points, r ² for all lines was ≥ 0.92. Data for three cell lines are shown. Identity of the cell lines is indicated above each graph. For C3H10T1/2 and Balb/3T3 clone A31 cells, the controls were pX17 infected and selected in G418. For Ψ-CRE cells the controls were uninfected Ψ-CRE.