Itpkb^−/− HSC have a cell intrinsically reduced long-term repopulating potential. (A) Chimerism (percent of CD45.2⁺ cells) among donor-derived peripheral blood granulocytes and macrophages ≥24 weeks after injection of 1:1 mixed Itpkb^−/− (gray bars) or WT (black bars) CD45.2⁺ donor and WT CD45.1⁺ competitor donor Lin⁻ BM into lethally irradiated CD45.1⁺CD45.2⁺ recipients. Statistical significance for the indicated comparisons was determined by unpaired Student t test. Representative of 3 independent experiments. Representative FACS data in supplemental Figure 2C. (B) Donor-derived LSK cell chimerism ≥24 weeks after BM transfer. Pooled data from 2 independent experiments. Representative FACS data are shown in supplemental Figure 2D. (C) BM LT-HSC, MPP1-3, common myeloid progenitor/granulocyte monocyte progenitor, and blood granulocyte and macrophage chimerism in lethally irradiated 2° recipients 14 weeks after reconstitution with BM from 1° recipients 29 weeks after injection of 1:1 mixed Itpkb^−/− or WT CD45.2⁺ and WT CD45.1⁺ competitor BM. Representative FACS data in supplemental Figure 2E. (D) BM total cell, LT-HSC, and MPP numbers in each 4 CD45.2⁺ lethally irradiated WT or Itpkb^−/− hosts 12 weeks after injection with CD45.1⁺CD45.2⁺ WT BM. Bars denote means.