CD41+LSK efficiently differentiate into megakaryocytic progenitor (MKP) and platelets in vivo. (A): (i) Five hundred CD41+LSK or Flt3+LSK from green fluorescent protein (GFP) transgenic mice were sorted and transplanted into lethally irradiated wild type B6 mice. Peripheral blood was analyzed by flow cytometry at the indicated time points after transplantation (n 5 5, each group). The frequency of GFP-positive cells in each lineage is shown. CD41+ Gr1/Mac1+, B220+, and CD3e+ represent platelets, granulocytes/monocytes, B cells, and T cells, respectively. (B):The frequencies of donor-derived cells at the early time point after transplantation were shown (right panel, day 7; left panel, day 11). Abbreviations: GFP, green fluorescent protein; LSK, lineage−Sca1+cKit+.