Transplantation of a single HSC gives rise to donor-derived ECs. (A) Portal vein from a recipient of a single GFP⁺ KSL cell 6 months after transplantation demonstrating the expression of CD31 (Cy3, red channel only). (B) High magnification of area in the box indicated in panel A, showing a GFP⁺ luminal cell (green channel only) integrated into the vessel wall. (C) Merged image, the box indicating the same donor GFP⁺ (green), CD31⁺ (red) EC with a DAPI⁺ nucleus (blue) (insert: high magnification of the same cell). (D) A GFP⁺, CD45^– EC within the vessel wall (solid arrow) and a CD45⁺ (red) leukocyte (open arrowhead). (E) The same GFP⁺, CD45^– EC sequentially labeled with VWF (red) (solid arrow). (F) A GFP⁺, CD45^– donor EC in a liver venous sinusoid (solid arrow) and a donor CD45⁺ (red) leukocyte (open arrowhead) 6 months after transplantation. (G) The same GFP⁺ CD45^– EC sequentially labeled with CD31 (red). (Scale bars: A, 20 μm; C: 20 μm; and D-G: 10 μm; DAPI⁺ nuclei (blue); L indicates lumen.) Original magnification, × 60 (B,C insert).