Phenotypic HSC expansion in Itpkb^−/− mice. (A) FACS analysis of BM HSC and MPP subsets in Itpkb^−/− and Itpkb^+/+ (WT) mice. Lin⁻, CD3⁻CD4⁻CD8⁻CD11b⁻CD11c⁻GR-1⁻DX5⁻B220⁻CD19⁻Ter119⁻IL-7Rα⁻. LSK, Lin⁻Sca-1⁺c-Kit⁺. The cell types in each gate are indicated in the top panels and gated populations are above the panels. Numbers indicate percent of total BM cells in the respective gate. (B) Total phenotypic LT-HSC, MPP1-4, and cell numbers in the BM and spleens of WT or Itpkb^−/− mice, pooled from 2 independent experiments. The P values for the indicated comparisons were obtained by unpaired t test (symbols, individual mice; horizontal bars, means). Age distributions of the mice were 9 to 11 weeks in the BM analysis (mean age = 9.8 weeks; standard deviation [SD] = 1 week; n = 6 per genotype) and in the spleen analysis (mean age = 9.6 weeks; SD = 0.9 weeks; n = 5 per genotype). Raw data is shown in supplemental Table 1.