Paf is necessary for proper HSC and progenitor development. (A) FACS of thymocytes from Paf+/+ and Paf−/− mice stained for intracellular PAF. (B) Total number of cells in BM, thymuses, and spleens of Paf+/+ and Paf−/− mice. (C) Representative staining profiles for BM HSC and progenitor populations. (D and E) Absolute cell numbers in the BM of 8-wk-old (D) or 6-mo-old (E) Paf+/+ and Paf−/− mice. (F) Representative staining profiles and absolute number of CLPs in the BM of 8-wk- and 6-mo-old mice. Plots are gated for Lin−Sca-1lowc-kitlow cells as defined in (C). (G) Representative staining profiles and absolute cell numbers of ETPs in the thymus of 8-wk-old mice. (H) Representative staining profiles for myeloerythroid progenitors. LS−K cells (defined in C) were subdivided into CMPs, GMPs, and MEPs as indicated. (I and J). Absolute cell numbers of LS−Ks, CMPs, GMPs, and MEPs in the BM of 8-wk-old (I) or 6-mo-old (J) mice. Each symbol represents a mouse combined from 3–6 experiments. Horizontal bars indicate the mean. Numbers in parentheses are the fold change of cell numbers for Paf−/− relative to Paf+/+ mice. *, P < 0.05; **, P < 0.01; ***, P < 0.001.