Figure 2
From: Activin receptor-like kinase 1 is essential for placental vascular development in mice
Expression patterns of Alk1, Flk1, and Alk5 in E15.5 umbilical vessels. Transverse sections of whole-mount X-gal-stained umbilical vessels of Alk1+/lacZ (a, b), Tg(Alk1-lacZ) (c, d), Flk1+/lacZ (e, f), and Alk5+/lacZ (g, h) embryos were counterstained with NFR (a, c, e, g) or anti-αSMA antibodies (b, d, f, h). Note that X-gal-positive cells were mostly detected in the endothelium of the umbilical artery (UA) of Alk1+/lacZ (a, b) and Tg(Alk1-lacZ) embryos (c, d). X-gal-staining intensity was stronger in the umbilical vein (UV) than in the UA, and capillaries in the medial and adventitial areas were also X-gal-positive in Flk1+/lacZ mice (e, f). X-gal-positive cells were localized in smooth muscle layers, but not in endothelium of the UA and UV in Alk5+/lacZ (g, h). A high-magnification view of the UA is shown as an inset in (g).
