Recombination of Gata1 in vivo affects monocytic/DC lineage development. (A) Western blot of WT and KO BM whole-cell extracts after 4 weeks of Tx treatment. Npm1 was used as loading control. (B) CFU-GEMM assays performed on the BM of WT and KO mice after 4 weeks of Tx treatment. GEMM indicates granulocyte erythroid monocyte megakaryocyte; GM, granulocyte monocyte; G, granulocyte; and M, monocyte. Error bars indicate SD. (C) Dot plots depicting the numbers of different leukocytes (defined by flow cytometry; Figure 1F) in the blood after 4 weeks of Tx treatment. Circles represent cell numbers/μL blood in Tx-treated WT mice (n = 4, gray circles) and in Tx-treated KO mice (n = 6, white circles). Thick horizontal lines represent the average cell numbers/μL blood. Mo indicates monocytes; and pDCs, plasmacytoid dendritic cells. The P values are derived from Mann-Whitney statistical analysis of independent samples. (D; left) Dot plots depicting the frequency of mDCs and Mfs (defined by flow cytometry; Figure 1F,G) in the spleen after 4 weeks of Tx treatment. (Right) Immunohistochemistry of the spleen after 4 weeks of Tx treatment. Sections were stained with antibodies against CD11c (brown; monocytes and mDCs) and B220 (blue; B cells) or MOMA-1 (blue; Mfs). Images collected using a Leica DM-LB microscope (Leica, Wetzlar, Germany). Camera used was a Leica DC-500. A 10×/0.30 NA dry objective was used. Pictures were taken in slides. The acquisition software used was Imaging for Windows (Kodak), belonging to Windows 2000 SP4.