Figure 4.

The effect of PD 98059 on cell-cycle progression in the absence of aphidicolin treatment. Cells were plated at low density and grown in low serum for 48 hr. PDGF was added to induce them to enter the cell cycle. After 20 hr, when the cells had all entered the cell cycle, PD 98059 was added to 100 μM or an equivalent volume of DMSO. Cells were collected and stained with PI for FACS at 37 and 43 hr after serum stimulation.