FIG. 3.

Expression of E4-16K in keratinocytes induces a G₂ arrest in the cell cycle. (A) Cell cycle analysis of SCC-12F and HeLa keratinocytes either mock infected or infected with rAds expressing the full-length E4-17K protein, the truncated E4-16K protein, or β-galactosidase (β-Gal). Cell cycle analysis was performed at 24, 48, 72, and 96 h p. i., but only the 24- and 72-h time points are shown. Arrows indicate the accumulation of E4-16K cells with a DNA content of greater than 4N. Results shown are representative of at least four independent experiments. (B) Western blot analysis of equivalent amounts of cell lysates prepared from HeLa cells expressing β-galactosidase and E4 proteins. Immunoblots were processed with E4 and β-galactosidase MAbs. (C) The percentage of mitotically arrested HeLa cells expressing β-galactosidase, E4-17K, and E4-16K, as determined by immunofluorescence staining. The data are derived from three experiments, and for each experiment a minimum of 200 cells were counted per transgene.