Fig. 6.

Runx1 is required for HSC maturation prior to E11.5 in the AGM+U+V. (A) Schematic for deletion of Runx1 ex vivo. E11.5 AGM+U+V (CD45.2⁺) were explanted in 4-OHT for three days, dissociated, and transplanted into irradiated CD45.1⁺ hosts with 250,000 CD45.1/CD45.2 spleen cells. Recipients were analyzed 16 weeks post-transplantation, and CD45.2⁺ donor cells (mean±s.e.m.) sorted from bone marrow and thymus of reconstituted recipients and analyzed for Runx1 deletion by PCR, as described in Fig. 4. (B) Percentage of donor-derived cells in the bone marrow 16 weeks post-transplantation following deletion with Actb-Cre^ERT. Contribution to peripheral blood was similar to bone marrow (not shown). Embryonic equivalents of 1.0 and 1.6 were transplanted. (C) PCR analysis of Runx1 alleles from Actb-Cre^ERT donor-derived colonies picked from methylcellulose cultures. Number of colonies assayed=31 for f/+; Actb-Cre^ERT and 137 for f/f; Actb-Cre^ERT. Each bar represents colonies from an independent recipient mouse. (D) Percentage of donor-derived cells (mean±s.e.m.) in the bone marrow 16 weeks post-transplantation following deletion with VEC-Cre^ERT. Contribution to peripheral blood was similar to bone marrow (not shown). Embryonic equivalent of 0.2 was transplanted. (E) PCR analysis of Runx1 alleles from VEC-Cre^ERT deleted donor-derived colonies picked from methylcellulose cultures from individual recipients. Number of colonies assayed=106 for f/+; VEC-Cre^ERT and 60 for f/f; VEC-Cre^ERT. Each bar represents colonies from an independent recipient mouse.