Expression of α₉β₁ on human CB and murine BM cells. Sorted lin⁻CD34⁺ CB cells (A) gated for CD38^low (R1) and CD90^high (B, R2, 20%), then analyzed for α₉β₁ expression (C). Cell surface expression of α₉β₁ on Lin⁻CD34⁺CD38⁻CD90^bright cells was clearly evident by fluorescence microscopy (D). Endosteal BM sorted for LSK (E, R1) were gated for CD34^low (F, R2, < 10%) and analyzed for α₉ expression (G). Red line represents specific antibody staining, blue line represents unstained control. Cell surface expression of α₉ on Lin⁻Sca⁺Kit⁺CD34⁻ cells was clearly evident by fluorescence microscopy (H). Lysates made from 3 individual sorted human CB Lin⁻CD34⁺CD38⁻ cells (lanes 2-4) demonstrate the presence of α₉ and β₁. Isotype control is in lane 5. (I). Sorted human CB Lin⁻CD34⁺CD38⁻CD90^bright HSCs (lane 2) and murine BM Lin⁻Sca⁺Kit⁺CD34⁻ HSCs (lane 3) express α₉ gene when analyzed by real-time PCR. (J). Figure shows one representative example of 3 independent biological repeats from each cell population. Scale bar = 5 μm.