G1 cell-cycle arrest induced by C/EBPα and its variants.

The indicated 32DPKCδ cell lines were cultured in the absence or presence of estradiol (E2) for 48 hours, and then the proportion of cells in the G1, S, and G2/M cell-cycle phases was determined by staining with propidium iodide followed by FACS analysis. The G1/S ratio observed in the presence of estradiol divided by the G1/S ratio observed in its absence is shown (mean and SE from 2 determinations). An increased G1/S ratio reflects slowed G1 to S progression.