Expression of differentiation markers in mGATA-1–infected MGS in the presence of cytokines. (A) MGS cells were cultured in a medium supplemented with cytokines (EPO, TPO, IL-3, SCF, and GM-CSF), and the frequency of differentiation marker–positive cells was examined. Examined were 4 differentiation markers. Blue columns represent MGS cells without infection, while dark green columns represent MGS cells infected with the empty MSCV vector. Red columns indicate MGS cells infected with MSCV–mGATA-1, and yellow columns represent MGS cells infected with ΔNT. (B) Giemsa staining of MGS cells. No significant morphologic differences were observed among MGS cells infected with MSCV–mGATA-1, MSCV vector, and ΔNT. Original magnification, × 1000.