GFP^- ECs in the VECDp-5′ Int1- egfp. Flat-mount specimen of a retina of an 8-week-old VECDp-5′ Int1-egfp transgenic mouse was stained with (A) anti-PECAM-1 mAb (red) (B) anti-GFP antibody (green). Arrows indicate a venous trunk in this retina, in which GFP expression was not detected. (C) Overlay. In one experiment (C-D), neo-angiogenesis was induced in the cornea of this transgenic strain. Whole-mount specimen of a newly formed vascular plexus was stained by (D) anti-PECAM-1 mAb (red) and (E) anti-GFP antibody (green). (F) Overlay. Only portions of ECs in this region are GFP⁺, and they are distributed randomly.