T-cell development alterations in Cbfb^−/GFP and Cbfb^GFP/GFP embryos. (A) Representative contour plots of cell surface marker expression of thymocytes from Cbfb^+/+, Cbfb^+/GFP, and Cbfb^−/GFP embryos at E17.5. The cells were stained with CD4, CD8, CD44, and CD25. The top panels show CD4 and CD8 distribution, and the bottom panels show CD44 and CD25 staining of DN cells. (B) CD4 expression in immature thymocytes from E17.5 embryos. The left panel shows the histogram overlay of CD4 expression in TCRβ^loFSC^hiCD8^−/lo thymocytes of wild-type (filled gray line), Cbfb^−/GFP, and Cbfb^GFP/GFP mice (black line). The right panel shows the MFI of CD4 expression in TCRβ^loFSC^hiCD8^−/lo cells from wild-type (n = 7), Cbfb^−/GFP (n = 6), and Cbfb^GFP/GFP (n = 8). (C) Total thymocyte numbers from embryos at E17.5. The panel shows the means and SDs of wild-type (WT, n = 4), Cbfb^+/GFP (+/GFP, n = 8), Cbfb^+/−(+/−, n = 3), Cbfb^GFP/GFP (GFP/GFP, n = 6), and Cbfb^−/GFP (−/GFP, n = 6) embryos. (D) Summary of T-cell phenotypes of Cbfb^GFP/GFP, Cbfb^−/GFP, Cbfb-MYH11 chimera, and Tg(Lck-Cre)/Cbfb^+/56M mice. The top panel shows the mouse thymocyte developmental diagram. The crosses in the lower panel indicate block of differentiation at the corresponding stages. The arrows in the lower panel indicate increase or decrease in percentage of the population, or apoptosis; − indicates no change.