Endosialin expression in newborn (A-F) and adult (G-L) mouse tissues. Newborn liver (A), small intestine (B), and heart (C) lack endosialin immunostaining, whereas newborn brain capillaries are endosialin-positive (D), and newborn kidney glomeruli show endosialin expression in mesenchymal cells (E; insert with higher magnification). This pattern differed markedly from that seen with the pan-endothelial marker CD31 (F). Among the adult mouse tissues tested (G-L), the cerebellum (G), cerebral cortex (H), liver (I) and lung (J) lack detectable endosialin expression. In the adult kidney (K), endosialin maps to some glomeruli with a mesenchymal pattern, and in the uterus of pregnant mice (L), endosialin is expressed in fibroblastic stromal cells, but not in the lining epithelium or smooth muscle layer. Scale bars: 125 µm (C); 50 µm (A, B, G, J, L); or 25 µm (D-F, H, I, K).