Severe defects in B, T, and NK cell precursors and lymphoid progenitor compartments in recipient mice engrafted with Lin⁻ BM cells (CD45.1⁻). Lethally irradiated recipient mice (CD45.1⁺) engrafted with BM cells of indicated genotypes were treated with Tam and analyzed 4 wk later (n = 4/group, and the experiment was repeated 4 times). Panels show total cell numbers (bar graphs) and/or flow cytometry dot plots of donor BM B cells (A), donor thymocytes (B), donor BM NK cells (C and D), and donor lymphoid progenitors (E). Numbers in the flow cytometry plots refer to percentages of gated cells in total donor nucleated BM cells or thymocytes. *, P < 0.05; **, P < 0.01.