BM B cell phenotypes in Sh2b3 ^E372K and Sh2b3 ^R530Q mice. (A–I) BM B cell phenotypes. (A) Representative flow cytometric plot showing the gating of B cell precursors (IgM⁻IgD⁻), immature (IgM⁺IgD⁻), and mature (IgD⁺) B cells. Cells were pregated on B220⁺ lymphocytes. (B) Frequencies of B cell precursors as percentages of BM B cells. (C) Representative flow cytometric plot showing the gating of pre-pro (CD24⁻CD43⁺), pro- (CD24^hiCD43⁺), and pre-B cells (CD24⁺CD43^−/lo). Frequencies of pre-B cells as percentages of BM B cells in (D) Sh2b3^E372K (left) and Sh2b3^R530Q (right) mice and (E) 50:50 BM chimeras of CD45.1-Sh2b3^+/+ and CD45.2-Sh2b3^+/+/Sh2b3^E372K/E372K mice (n = 5). Frequencies of (F) pre-pro and (G) pro-, (H) immature, and (I) mature cells as percentages of BM B cells. Lines in all dot plots show means, and results are representative of two independent experiments. Each dot represents one mouse, and sample numbers for each group in B, D, and F–M are listed as follows: Sh2b3^E372K panels: +/+ (n = 4), E372K/+ (n = 3), E372K/E372K (n = 4); Sh2b3^R530Q panels: +/+ (n = 2), R530Q/+ (n = 4), R530Q/R530Q (n = 4). One-way ANOVA was used for statistical analysis of immunophenotyping data (B, D, and F–M), and Student’s t test was used for analyzing data from BM chimera experiments (E). Significance levels of one-way ANOVAs are indicated with asterisks, while those of Student’s t tests are indicated with hashes. Significance level criteria are indicated as follows: */#: P < 0.05, ***: P < 0.001.