BAF53a is essential for adult hemopoiesis. (A) Absolute numbers of BM myeloid progenitors (Mac1⁺/Gr1⁺), macrophages (Mac1⁺), granulocytes (Gr1⁺), B cells (B220⁺), T cells (CD3⁺), erythroid cells (Ter119⁺), B-type progenitors (B220⁺IgM⁺), and megakaryocytes (CD41⁺Gr1⁻) in control, BAF53a^fl/+Cre⁺, and BAF53a^fl/flCre⁺ pIpC-treated animals (days 12-18). Data are mean ± SD; n > 5 per genotype. (B) Representative FACS profiles of BM myeloid (Mac1⁺Gr1⁺) and erythroid (CD71⁺Ter119⁺) progenitor populations in pIpC-treated BAF53a^fl/flCre⁺ mice (day 16). RI: proerythroblasts (Ter119^lowCD71^hi); RII: basophilic erythroblasts (Ter119^hiCD71^hi); RIII: late erythroblasts (Ter119^hiCD71^med); and RIV: late erythroblasts (Ter119^hiCD71^low). (C) Representative images of BM cell suspensions isolated from pIpC-treated BAF53a^fl/flCre⁺ and control mice (day 16). (D) Absolute number of spleen myeloid (Mac1⁺Gr1⁺) and erythroid (CD71⁺/Ter119⁺) progenitors in BAF53a^fl/+Cre⁺ and BAF53a^fl/flCre⁺ pIpC-treated mice (days 12-18). n > 5 per genotype. (E) Representative FACS profiles of spleen erythroid progenitors (CD71⁺Ter119⁺) in BAF53a^fl/flCre⁺ mice after pIpC-induced deletion (day 16). Populations are as in panel B. (F) Hematoxylin and eosin staining of transversal sections of the femoral trabecular zone of pIpC-treated BAF53a^fl/flCre⁺ (KO) mice showing BM failure (day 14). Original magnification ×20. (G) Cytospin preparations of BM cells isolated from pIpC-treated BAF53a^fl/flCre⁺ mice (day 14). Original magnification ×20. *P ≤ .1 (Student t test). **P ≤ .01 (Student t test).