Impaired lymphopoesis in the absence of Mll5. (A-C) Flow cytometric analysis of thymocytes from 10- to 14-week-old Mll5^−/− mice (KO/KO) and WT littermates (WT/WT). (Left dot plots) Data from 1 representative staining. Total thymocyte numbers are given on top of the CD4/CD8 panels. (Right bar graphs) Total number of cells with the indicated immunophenotype, as average per animal plus or minus SD (n = 7). represents Mll5^−/− mice; ■, WT littermates. (D) Competitive BM reconstitution into alymphoid Rag2^−/−γc^−/− recipients. FACS-sorted Lin-negative BM cells (CD45.2) from Mll5^−/− mice (KO) or WT littermates were mixed with an equal number of Lin-negative competitor cells (CD45.1) and injected into sublethally irradiated (400 cGy) recipients. Individual recipients reconstituted with Mll5^−/− donor cells (○) or donor cells from WT littermates (●) are shown (data from 2 independent experiments combined).