Schematic illustration of the isolation of Lin^-, LKS⁺, and LKS^- cells. BM-MNCs and Lin^- cells were isolated as described previously.¹²  Lin^- cells were labeled with streptavidin-FITC, anti-Sca-1-PE, and anti-c-Kit-APC after preincubation with anti-CD16/32 to block Fcγ receptors. After washing, the cells were resuspended in PBS containing 1 μg/mL propidium iodide (Molecular Probes) and then sorted immediately using a FACStarPlus cell sorter (Becton Dickinson). LKS^- cells were sorted directly from R3 gate. LKS⁺ cells were first enriched by collecting c-Kit⁺ cells via presorting and then sorted from R4 gate.