GATA-1 complementation induces erythromegakaryocytic maturation in Gata1^- fetal liver chimera-derived G1ME cells. Cells were transduced with GATA-1 or control retrovirus and analyzed for maturation as described in Figure 3. (A) Ter119 expression after rescue by GATA-1. Percentages in top panels refer to fraction of GFP⁺ cells expressing Ter119. (B) GPIb expression after rescue by GATA-1. Percentages in panels refer to fraction of GFP⁺ cells expressing GPIb. (C) Cell morphology after retroviral expression; (top) benzidine stain for hemoglobin, (bottom) May-Gr̈nwald-Giemsa staining. Original magnification, × 400. Photographs were taken by using a microscope (Axioskop 2; Carl Zeiss) equipped with a color digital camera (Axiocam; Carl Zeiss).