Reduced levels of c-Myb are sufficient for intense proliferation of immature erythroid progenitors. Fetal liver cells from E14 c-myb+/+ and c-mybKD/KD embryos were plated in SP34 medium containing SCF (100 μg/mL), EPO (2 U/mL), and dexamethasone (1 μM). (A) At day 9 of culture, cells were stained with α-CD71 (FITC) and α-TER119 (APC) and analyzed by flow cytometry. (B) At day 9 of culture, cells were transferred to media favoring terminal erythroid differentiation and cultured for 3 additional days before being analyzed by flow cytometry for CD71 and TER119 expression. (C) At day 9 of culture in SP34, cells were permeabilized with 0.1% NP-40 and stained with 25 μg/mL propidium iodide for flow cytometric analysis of DNA content. Histograms represent linear fluorescence intensities.
