Differentiation potential of BM cells transduced with D816Y/V KIT and control vectors. (A) Total numbers of colonies from 105 cultured WT (wt) or Cbfb+/56m; Tg(Mx1-Cre) BM cells transduced with retroviral vectors containing WT KIT, KITD816V or GFP and sorted for GFP expression. Wt + GFP indicates WT BM cells transduced with GFP vector alone; Wt + KIT wt, WT BM cells transduced with WT KIT vector; and MxCre-CM + GFP, KIT wt, or D816Y, Cbfb+/56m; Tg(Mx1-Cre) BM cells transduced with GFP, Wt KIT, or KITD816V vector, respectively. The numbers above the bars are average colony numbers for the group. (B) Ratio of total colony numbers from 105 cultured WT or Cbfb+/56m; Tg(Mx1-Cre) (MxCre-CM) BM cells transduced with GFP versus those transduced with WT KIT. (C) Types of colonies formed from transduced Cbfb+/56m; Tg(Mx1-Cre) BM cells. CFU indicates colony-forming unit; G, granulocyte; E, erythrocyte; MM, monocyte and megakaryocyte; and GM, granulocyte and monocyte. All BM cells were sorted for GFP+ cells before plating. (D) Comparison of annexin V+ cell numbers (percentage) between the KIT (both WT and 816 mutants)–transduced (GFP+) and untransduced (GFP−) BM lin− cell populations, for both WT and Cbfb+/56m; Tg(Mx1-Cre). (E) Comparison of annexin V+ cell numbers (percentage) between the WT and Cbfb+/56m; Tg(Mx1-Cre) BM lin− cell populations that were transduced with WT KIT or KIT816Y/V. (F) BrdU+ cells in KIT (WT and 816 mutants)–transduced BM cells.