GATA1-Cre–mediated recombination of the

loxPiga allele in megakaryocytes, mast cells, and eosinophils. Liquid cultures enriched in megakaryocytes (panels A and B), mast cells (panels C and D), eosinophils (panels E and F), and granulocytes (panels G and H) were performed as described. Bulk cultures were analyzed for the wild-type (wt), loxPiga, and ΔPiga allele by PCR. Panels on the right show the PCR analysis for each culture system. Panels A, C, E, G, and H are May-Grünwald-Giemsa stains from cultures obtained from GL animals. Panel B shows acetylcholinesterase activity in GL megakaryocytes; panel C shows Toluidine Blue–positive GL mast cells; and panel E shows Luxol Fast Blue–positive GL eosinophils. L stands for DNA isolated from cultured cells from L^+/− control mice; GL for DNA isolated from cultured cells from G^+/−L^+/− mice; + and − represent positive and negative PCR controls. For granulocyte cultures G^+/−L^+/+ mice and L^+/+ control mice were used instead. Amplification products representing the wt,loxPiga, and ΔPiga allele are indicated.