Preferential expression of Tmtsp protein on hematopoietic stem and progenitor cells. (A) Expression of Tmtsp in c-Kit⁺Sca-1⁺Lin^– (KSL) fraction in the adult mouse BM. Tmtsp protein was highly expressed on both CD34^–KSL HSCs and CD34⁺KSL multipotential progenitor cell fractions. The number in the diagram indicates the percentage of cells in the fraction. Open and shaded curves represent cells stained with the anti-Tmtsp antibody and an isotype control, respectively. (B) Expression of Tmtsp protein on lineage marker–positive hematopoietic cells. Tmtsp was not detected on lineage marker–positive cells except for CD4^–CD8^– (DN) cells in the thymus.