A-F, Immunostaining on EMCN (red) and IB4 (blue) in PN 7 retinas of control (SclCreER-negative Eng-iKO, A and D), SclCreER;Eng-iKO (B and E), and SclCreER;Eng-iKO;ALK1-OE (C and F) mice. Merged images of EMCN, GFP, and IB4 (D-F). G-L, JAG1 (red) expression in PN7 retinas of controls (G and J), SclCreER;Eng-iKO (H and K), and SclCreER;Eng-iKO;ALK1-OE (I and L) mice. ECs are marked with IB4 (blue) staining. GFP signals in IB4-stained retinal ECs (J-L). Yellow arrowheads indicate AVMs in the retinal vasculature. a, artery; v, vein. Scale bars: 100 μm.