Differentiation induction into megakaryocytes, erythroid cells, and macrophages and LacZ expression driven by the GPIIb promoter and EF1- promoter in these cells.

Hematopoietic cells were generated from ES cells by the addition of TPO (A, E, I), EPO (B, F, J for primitive embryonic erythrocytes and C, G, K for definitive adult erythrocytes), and M-CSF (D, H, L) for megakaryocytes, erythroid cells, and macrophages, respectively. May-Grunwald Giemsa staining was used to detect morphologic features (A-D). The LacZ gene driven by the GPIIb promoter from −598 to +33 (E-H) and the elongation factor-1α promoter (I-L) were transfected into ES cells with a plasmid carrying the neomycin-resistant gene. Differentiation induction was carried out after G418 selection, and the cells were stained with X-gal. Double staining with AChE was performed to confirm LacZ expression in megakaryocytes.