Wip1 deficiency impairs early B-cell development. (A) Representative FACS plots of developing B cells in the bone marrow of WT and Wip1KO mice are shown. The percentage of pro-B and pre–B cells (B) and immature and mature B cells (C) in WT and Wip1KO mice is shown. The number of pro-B and pre–B cells (D) and immature and mature B cells (E) in WT and Wip1KO mice is summarized. (F) Representative FACS plots of pro-B and pre–B cells in the gated Lin⁻B220^low BMCs. (G-H) The percentage and number of pro-B and pre–B cells in the bone marrow of WT and Wip1KO mice are summarized. Data are expressed as means ± SD (n ≥ 30). (I) Wip1 mRNA expression in pre-pro–B, pro-B, pre-B, immature B, and mature B cells of 2-month-old mice was analyzed by real-time PCR. Results are standardized to β-actin and expressed as means ± SD (n = 5). *P < .05, **P < .01, and ***P < .001 compared with WT mice or between the indicated groups.