Reduced number of immature B cells in the blood of Eμ/miR-125b-Tg mice. (A) Representative flow cytometric analysis of Hardy fractions for B cell progenitor subpopulations in the bone marrow of 8-week-old Eμ/miR-125b-Tg and control mice. Hardy fractions in bone marrow (A-F) were gated as follows: fraction A, pre/pro-B cell (B220⁺CD43⁺BP-1⁻CD24⁻); fraction BC, pro-B cells (B220⁺CD43⁺BP-1⁻CD24⁺ and B220⁺CD43⁺BP-1⁺CD24⁺); fraction D, pre-B cells (B220⁺CD43⁻IgM⁻IgD⁻); fraction E, immature B cells (B220⁺CD43⁻IgM⁺IgD⁻); and fraction F, mature B cells (B220⁺CD43⁻IgM⁺IgD⁺); the C′ fraction (B220⁺CD43⁺BP-1⁺CD24^hi) was not resolved. (B) The frequency and number of each B-cell subpopulation in Eμ/miR-125b-Tg and control mice. (C) Representative flow cytometric analysis of immature and mature B-cell populations in peripheral blood of 8-week-old Eμ/miR-125b-Tg and control mice. Immature B cells were identified as B220⁺IgD^lowIgM^high, B220⁺CD93⁺, and B220⁺CD62L^low, and mature B cells were identified as B220⁺IgD^highIgM^low, B220⁺CD93⁻, and B220⁺CD62L^high. (D) The number and frequency of immature B cells (B220⁺CD93⁺) in the blood of Eμ/miR-125b-Tg and control mice. Bars represent mean values of pooled data. Data are pooled from 2 to 3 experiments and represent mean ± SEM (n = 8 mice per group). *P < .05; ***P < .001; NS, not significant.