FIG. 1.

Demonstration of the irreversible arrest in HeLa cell proliferation (A) and cell cycle perturbation (B) triggered by E22. Cells were exposed for 4 h to E2348/69 or E22 or left uninfected, and they were further cultivated for the indicated times. (A) Cell proliferation after interaction. Cultures were fixed and stained with Giemsa, and cells within random microscope fields were counted (objective, ×20). Each point is the mean of four independent measures. (B) Cell distribution according to DNA content, analyzed by flow cytometry after staining of DNA with propidium iodide. The percentages of cell populations are shown in each case.