An Flk-1⁺ origin for blood cells of adult Flk1^+/Cre;Rosa26R-EYFP mice. (A) Representative FACS plots of BM staining for the hematopoietic marker CD45 (y-axis) and EYFP (x-axis) to assess the origin of hematopoietic cells within the BM of 3-month-old Flk1^+/Cre;Rosa26R-EYFP mice. (B) Summary data of multiple experiments analyzing BM of Flk1^+/Cre;Rosa26R-EYFP mice. Numbers above bars indicate percentage of CD45⁺ cells that are either EYFP⁺ or EYFP⁻. The bars represent SD of the mean percentage of total CD 45⁺ cells.(C) Representative FACS plots of PB staining for the hematopoietic marker CD45 (y-axis) and EYFP (x-axis) to assess the origin of hematopoietic cells within the PB. Individual lineage markers were also assessed to examine if all mature blood lineages are indeed Flk-1⁺ in origin. Hematopoietic lineages analyzed include CD4 and CD8, T cells; B220, B cells; Gr1, granulocytes; and Mac1, macrophages. (D) Summary data of multiple experiments (n = 4) analyzing PB of Flk1^+Cre;Rosa26R-EYFP mice. Numbers above bars indicate percentage of CD45⁺ cells that are either EYFP⁻ or EYFP⁺, respectively. The bars represent SD of the mean percentage of total CD45⁺ cells.