Expression of erythroid differentiation markers in GFP/high and GFP/low MGS cells. MGS cells infected with MSCV–mGATA-1 (GATA-1) or ΔNT (GATA-1 dNT) were cultured without cytokines, and the expression of CD34 and glycophorin A was analyzed. Upper panels show whole GFP-positive fractions of MGS cells. Middle and lower panels show GFP/low and GFP/high fractions, respectively.