Effect of high and low nocodazole treatment on the cell cycle in synchronized LXSN and AS21 cells. Cells were synchronized by growth factor starvation for 18 hours and then released by adding back growth factor (GM-CSF) in the presence or absence of the indicated amount of nocodazole and incubation for 24 hours before cell cycle analysis. Nocodazole concentrations were the same as described in Fig5. The 4N proportion at time zero was negligible. Data are representative of three separate experiments.