Epo cooperates with GATA-1 to maximize bcl-x induction and G1E-ER2 cell viability during terminal maturation. (A) Viability of G1E-ER2 cells cultured with various combinations of Epo and E2. Live and dead cells were quantitated using calcein AM and ethidium bromide, respectively. Note that Epo is required for cell survival only during estradiol-induced terminal maturation. (B) Effects of Epo starvation on bcl-x and β-globin mRNA expression in G1E-ER2 cells. Cells were cultured with the indicated combinations of Epo and/or estradiol (E2), sampled at various times and analyzed for gene expression by Northern blotting. Note that Epo and GATA-1 can induce bcl-xL mRNA independently, although both are required for maximal expression. Each lane contains 20 μg of total RNA.
