Dysregulation of the aortic endothelium in CV2-deficient mice. (A-C) Aortic expression of CD31 and VE-cadherin in Cv2^+/+ (wild-type), Cv2^+/−, and Cv2^−/− mice by (A) real-time PCR, (B) immunoblotting, and (C) immunofluorescence. β-actin is shown for comparison in the immunoblot (n = 3). (D) Vascular expression of CD31 in kidney, lung, and liver of wild-type and Cv2^−/− mice by immunofluorescence. (E) Aortic expression of Ephrin B2, and CD31 and α-SM-actin in wild-type and Cv2^−/− mice by immunofluorescence and immunoblotting. (F) Colocalization of (top) BMP-9 and CV2, and (bottom) BMP-4 and CV2 in the aortic endothelium of wild-type mice, but not Cv2^−/− mice, by immunofluorescence. (G-I) Aortic expression of ALK2, ALK1, MGP, BMP-4, ALK5, VEGF, BMP-9, and TGF-β1, and liver expression of BMP-9 in Cv2^+/+, Cv2^+/−, and Cv2^−/− mice by (G) real-time PCR, (H) immunoblotting, and (I) immunofluorescence, (n = 3). (J) Schematic working model for MGP and CV2 based on Shao et al²  and Yao et al.^5,6,22  Nuclei are visualized by DAPI (blue fluorescence). Asterisks indicate statistically significant differences compared with Cv2^+/+ (wild-type) mice. *P < .05, **P < .01, ***P < .001, Tukey test.