Fes is involved in EPO-induced cell growth in UT-7/EPO cells.

(A) The expression of Fes in the transfectant clones. UT-7/EPO cells were transfected with expression vector containing the kinase-negative form of c-fes cDNA. Three neomycin-resistant clones were chosen, and the expression of the dominant-negative form of Fes was monitored by Western blotting. (B) The effect of the dominant-negative form of Fes on EPO-induced Stat1 and Stat3 activation. The parental UT-7/EPO and the transfectant cells were starved of cytokine for 24 hours and then stimulated with EPO (10 U/mL) for 15 minutes. Nuclear extracts were analyzed by EMSA using SIE and β-CAP probes. (C) The growth response curve of parental UT-7/EPO and the transfectant cells expressing the mutant FES. MTT reduction assay was performed after 3 days of culture. The values represent the mean ± SD from triplicate cultures.