Figure 4.

Equine iTr cells require MEK/ERK signals for proliferation. Equine iTr cells were treated with the respective growth factors in the presence or absence of 1 nM PD0325901, an MEK inhibitor. Lysates were analyzed by western blot for total and phosphorylated ERK1/2 (A). Parallel plates of cells were treated in a similar manner with EdU included 2 h prior to fixation. Total and EdU(+) cells were enumerated (B). Means and SEMs of three replicate experiments shown. Different letters represent significance at P < 0.05.