FVB/TgN transgenic mouse bone marrow transplantation model. (A) Flow chart of the experimental procedure. BM from FVB/TgN transgenic mice, expressing GFP under the transcriptional control of the endothelial specific Tie2 promoter, was transplanted into lethally irradiated FVB/NJ wild-type recipients 30 days before treatment with AAV-VEGF. (B) Immunostaining for the endothelial-specific CD31 and GFP markers in muscle sections of VEGF-treated mice at 1 month after vector injection. In the FVB/TgN transgenic control mouse, most of the endothelial cells also stained positive for GFP (i-iii). In contrast, no Tie2-GFP–positive cells were found within the cellular infiltrates or incorporated into the wall of the newly formed vessels in the FVB/NJ-BMT TgN chimeric mice (iv-ix). Red indicates CD31⁺ cells; green, GFP; and blue, nuclei stained with DAPI.