Homing and spatial distribution of LSK populations. (A) Endosteal and central Lin⁻ cells stained with Sca-1, c-kit, CD150, and CD48 (clone HM48.1). Sketch shows sorting strategy. Individual endosteal and central cell populations were stained with CFDA-SE or SNARF-1 and cotransplanted into nonablated recipients. In addition, endosteal and central total LSK not stained with CD150 or CD48 were cotransplanted into nonablated recipients. (B) Homing efficiency was determined 15 hours after transplantation. (C) Spatial distribution of CD150⁺CD48⁻LSK and CD150⁺CD48⁺LSK was determined 15 hours after transplantation. Data are mean ± SEM. (D) SNARF labeled CD150⁺CD48⁻LSK homed to endosteal BM. Image was acquired on an Olympus BX51 microscope through a 20×/0.70 NA UplanApo objective using a cooled monochrome CCD Optronics Magnafire S99802 camera at 40°C below ambient and Magnafire software. Image brightness was adjusted using Adobe Photoshop.