Impaired multilineage hematopoietic repopulating ability of Gab2^−/− BM cells. Total BM cells (CD45.2) were collected from either Gab2^−/− or wild-type mice and mixed at a 1:1 donor equivalent ratio. The BM cell mixes were then injected into lethally irradiated recipient mice (CD45.1; 11 Gy [1100 rad]). (A) Mice that underwent primary transplantation were bled from the retro-orbital venous plexus 8, 12, and 16 weeks after transplantation and analyzed for CD45.2 expression by flow cytometry; mean donor chimerism was determined. *P > .001 relative to wild-type BM. (B) To demonstrate a typical lineage analysis of the Gab2^−/− engraftment, CD45.2 positive cells costaining for Gr-1, B220, Ter119, or CD4 are shown for lethally irradiated adult C57BL/6 CD45.1 recipient mice analyzed 16 weeks later. Error bars represent the average plus or minus a standard deviation. (C) The average multilineage analysis data for both experiments at 16 weeks after transplantation is shown. *P > .001 relative to wild-type BM.