Subpopulations of periendothelial BM-derived vascular mural cells express the pericyte marker NG2 proteolygan and/or the hematopoietic markers CD45 or CD11b. Angiogenesis was induced in mice that underwent BM transplantation by subcutaneous implantation of B16 melanoma (A, C-D) or by repeated subcutaneous VEGF protein injections (B), and the tissues were analyzed by confocal microscopy. (A) Some of the BM-derived mural cells covering angiogenic blood vessel endothelium (CD31 staining, blue) express the pericyte marker NG2 (red). (B) A 3-dimensional projection demonstrates that BM-derived GFP⁺ periendothelial cells encompass both cells expressing CD45 (arrowheads) and cells with no CD45 immunoreactivity (arrows). (C-D) Similarly, BM-derived NG2⁺ cells also include cells that do not coexpress CD45 or CD11b (arrows). Bars represent 30 μm.