Cell-autonomous requirements for Runx1 and Cbfb in the development of DCs. (A-B) A mixture of CD45.1/2 WT and either Cbfb-CKO or control Het BM cells (CD45.2) were transferred into lethally irradiated CD45.1 recipients, and reconstitution of BM progenitor populations (A) and spleen cDCs (B) was analyzed by flow cytometry. Percentages of HSCs (Sca1⁺CD135^–), LMPPs (Sca1⁺CD135⁺), and Flt3⁺ MDP/CLPs (Sca1^lo/–CD135⁺) in Lin^–c-kit⁺ BM cells, and CD11c⁺MHC-II⁺ cDCs in the spleen are shown. Data represent 4 mice with mean and standard deviation shown in panel C. (D-H) BM cells, splenocytes, and lung mononuclear cells from BM chimeras reconstituted with a mixture of CD45.1 WT and either Runx1-CKO or control Cre(–) Runx1^F/F BM cells (CD45.2) were analyzed for the presence of DC progenitors and mature DCs. Runx1-CKO or control BM-derived (CD45.1^–CD45.2⁺) HSCs (Sca1⁺CD135^–), LMPPs (Sca1⁺CD135⁺), and Flt3⁺MDP/CLPs (Sca1^lo/–CD135⁺) in Lin^–c-kit⁺ BM cells, CD11c⁺ MHC-II⁺ cDCs in B220^– cells in the spleen and lung, and CD11c⁺SiglecH⁺ pDCs in the spleen are shown. Data shown represent 5 mice and statistical analysis is shown in panel H. *P < .05; **P < .01.