Reconstitution and mobilization of integrin α6^−/− fetal liver HSCs. (A) FL cells (10⁶) from integrin α6^−/− (α6^−/−) embryos or wild-type littermates (α6^+/+) expressing CD45.2 isotype together with 1.5 × 10⁶ CD45.1 competitor adult BM cells were injected into lethally irradiated CD45.1 mice. Blood was harvested at 3, 6, 16, 30, and 40 weeks after transplantation. Shown is reconstitution of CD45.2⁺ cells and CD45.2 myeloid cells (Mac-1) of all nucleated cells (mean ± SD; n = 13-14/group at 3, 6, and 16 weeks and n = 3-4/group at 30 and 40 weeks). (B) After 17 weeks, BM cells were transplanted into secondary recipients and reconstitution was analyzed 12 weeks after transplantation. Data are pooled from 2 independent experiments. The horizontal bars show mean values for each measurement. (C) Schematic representation of HSPC mobilization. Mice reconstituted with integrin α6^−/− (α6^−/−) or wild-type (α6^+/+) FL cells (CD45.2), together with CD45.2 competitor cells, 5 and 8 months after transplantation, were injected subcutaneously with G-CSF for 3 days. On the fourth day, the femora and blood were collected and the cells in blood and BM were analyzed by flow cytometry. (D) Shown is the proportion of CD45.2⁺Lin⁻Sca-1⁺ cells of all Lin⁻Sca-1⁺ cells in BM and blood. The data are pooled since there was no difference of mobilization response in the 2 experiments.