Colony-forming ability of wt and Hhex^−/− CD41⁺CD45⁻c-kit⁺ cells. (A) The number of colonies obtained from day 6 to 8 sorted CD41⁺CD45⁻c-kit⁺ cells. Mixed lineage colony-forming unit (CFU-Mix), granulocyte-macrophage colony-forming unit (CFU-GM), and erythroid burst-forming unit (BFU-E) colonies were enumerated after 7 days in culture. Hhex^−/− did not show a significant change in the percentage of each colony type (CFU-GM, CFU-Mix, BFU-E) compared with wt Jet–derived colonies. The total number of colonies derived from Hhex^−/− day 6 and day 7 isolated CD41⁺CD45⁻c-kit⁺ cells was significantly reduced, whereas the total number of colonies from day 8 cells was relatively equivalent between the 2 samples; *P < .001. Error bars represent SD. The ‡ indicates the difference within the Hhex^−/− colonies over time; P < .005. (B) Colonies derived from day 8 flow-sorted wt (left) and Hhex^−/− (right) CD41⁺CD45⁻c-kit⁺ cells. Images were captured on Olympus IX50 inverted microscope; original magnification ×100, 10×/0.25 Ph1 objective; Olympus SC35 camera; Kodak 64T Tungsten film. (C) The total number of cells counted, from colonies obtained from day 6 to 8 sorted CD41⁺CD45⁻c-kit⁺ cells, after 7 days in culture. Error bars represent SD. *P < .05.