EE372 mediates hEGF-dependent CFUe development and synergizes with c-Kit. The ability of erythroid splenocytes from TAP-treated EE372 mice to form hemoglobinized colonies was assayed in the absence of cytokines or the presence of either Epo (5 U/mL), hEGF (20 ng/mL), SCF (50 ng/mL), Epo plus SCF, or hEGF plus SCF. Benzidine-positive colonies (CFUe) were scored at 48 hours of culture. Values are the means (± standard error) of 3 assays and are representative of 2 independent experiments.