FIG 4.

HPV16 E7 promotes the bypass of G₀ arrest in T98G cells. (A) T98G cells expressing wild-type SV40 small T (ST), SV40 ST C103S, HPV16 E6, HPV16 E7, HPV16 E7 ΔDLYC, or an empty vector (Empty) were grown in DMEM containing 0.1% FBS for 72 h, followed by BrdU labeling and propidium iodide (PI) staining for DNA content. An additional population of empty vector cells was maintained in 10% FBS and is included as a control. The percentage of cells in S phase was determined by flow cytometry. (B) Percentage of cells in S phase for T98G cells expressing HPV16 E6 or HPV16 E7 or containing the empty vector. The graph represents averages with standard deviations from three independent experiments, one of which is the experiment shown in panel A. A two-tailed t test was used to determine statistically significant differences between the groups, and selected P values are indicated on the graph.