FIG. 4.

Induction of mitotic markers and morphology in SV40-infected CV-1 cells incubated with caffeine. Confluent CV-1 cells were infected with wt SV40 at 100 PFU per cell and treated with mimosine as described in the legend to Fig. 1. Three hours after release from mimosine, the cells were incubated with 6 mM caffeine. Samples were harvested at the indicated times postaddition. (A) Induction of mitotic markers. Whole-cell lysates were resolved by SDS-PAGE and immunoblotted. Each filter was reacted with antibodies specific to each protein and then with alkaline phosphatase-conjugated goat anti-mouse or -rabbit antibody. Solid arrows indicate mitotic Cdc25C and mitotic MPP2. The mitotic control was prepared from uninfected CV-1 cells arrested by nocodazole (Noc). (B) Induction of P-H3 in SV40-infected cells. The attached cells were stained with anti-P-H3 and anti-large T antibodies and DAPI as described in the legend to Fig. 3. Cells from all of the time points were stained, but only samples from the time of addition and the last time point are shown. (C) Nuclear morphology change and P-H3 expression. Stained samples of DAPI and P-H3 from panel B were used. Normal mitotic condensation, filled circles; ACC, open circles; P-H3, filled triangles. Exp, experiment; Ag, antigen.