Defects in B and T-cell development in Mysm1^tm1a/tm1a mice. (A) Reduced absolute numbers and decreased frequency of B220⁺ B-lineage cells in the BM of Mysm1^tm1a/tm1a mice. (B) Reduced frequency of B cells in the blood of Mysm1^tm1a/tm1a mice, gated as CD45⁺CD19⁺ cells. (C) Decrease in the absolute number of pre-pro-B cells in Mysm1^tm1a/tm1a BM (gated as B220⁺CD19⁻CD43⁺CD11b⁻DX5⁻). (D) Relative increase in the proportion of pre-pro-B cells within the B220⁺ B-cell lineage gate in Mysm1^tm1a/tm1a BM. (E) Representative flow cytometric plots of wild-type and Mysm1^tm1a/tm1a BM, gated on lymphocytes and demonstrating a preferential loss of B220⁺CD19⁺ cells in Mysm1^tm1a/tm1a mice. (F) Reduction in the numbers of CD4⁻CD8⁻ double-negative (DN), CD4⁺CD8⁺ double-positive, and CD4⁺ and CD8⁺ single-positive thymocytes in the thymus of Mysm1^tm1a/tm1a mice. (G) Reduction in the numbers of CD44⁺CD25⁻ DN1, CD44^+/−CD25⁺ DN2-3, and CD44⁻CD25⁻ DN4 thymocytes in the thymus of Mysm1^tm1a/tm1a mice. Bars represent mean ± SEM. *P < .05, **P < .01, ***P < .001 using the Student t test or the Mann-Whitney test; all BM cell counts are per 1 tibia and femur.