Constitutive activation of AKT synergizes with NOTCH during in vitro megakaryopoiesis. (A) Sorted wild-type LSK cells and CMPs were transduced with retroviruses encoding either MIG or myr-AKT and subsequently plated on OP9-DL1 stroma in the presence or absence of GSI. Contour plots show a representative of 5 independent experiments. (B) Bar graphs represent mean ± SEM from 5 independent experiments described in panel A. (C) Wild-type CMPs were infected with an empty control (MIG) or myr-AKT vector, plated on OP9-DL1 stroma for 4 days, and analyzed for phospho-FOXO by flow cytometry. A representative analysis gated on CD45⁺ hematopoietic cells is shown.