Figure 3.

FACS analysis of ERK dependency in mediating PMA‐induced G₂‐phase arrest. HeLa cells were synchronized at the G₁/S boundary and released back into the cell cycle. Cells were left untreated (control), treated with PMA (0.1 µm) at 7 h after release, treated with U0126 (10 µm) at 6.5 h after G₁/S release or treated with PMA and U0126 together. Cells were harvested at the times indicated after release from G₁/S and the number of cells (Y axis) containing 2N or 4N DNA content (X axis) were determined by FACS.