LacZ/ephrin-B2 expression in mouse embryo and adult mouse vascular tissue.

E9.5 embryos from ephrin-B2 heterozygous and wild-type embryos, abdominal/thoracic aorta, and superior/inferior vena cava with surrounding tissues from adult ephrin-B2 heterozygous or wild-type mice were stained with LacZ staining solution. After LacZ staining, the samples were postfixed, embedded, and sectioned. Then the vascular ECs and surrounding cells/SMCs were examined by immunochemical staining with anti–PECAM-1 and anti–α-SMA antibodies. No LacZ staining was observed in wild-type embryos or in adult tissue. In ephrin-B2 heterozygous embryos, LacZ/ephrin-B2 (blue) was obviously detected in the dorsal aorta (da) ECs and surrounding cells with PECAM-1 (red) and α-SMA (red) (arrowheads) but not in the anterior cardinal vein (acv). In adult tissue the LacZ/ephrin-B2 was coexpressed with PECAM-1 and α-SMA in the arterial ECs and SMCs but not in the venous ECs and SMCs. PECAM-1– and α-SMA–stained cells were identical in expression to the arterial ECs and SMCs in wild-type mice; a indicates aorta; v, vena cava. The bar indicates 25 μm.