Endothelial expression of the CAT gene in various tissues of E13.5 embryos. Embryo sections were hybridized withCAT (A-E) or VE-cadherin (A′-E′) antisense transcripts. Comparison of gene expression in aorta (A-A′), heart (B-B′), intestine (C-C′), lung (D-D′), and liver (E-E′). Scale bars represent 50 μm (A-A′) or 100 μm (B-E, B′-E′); b, bronchi; c, capillary; e, endocardium; my, myocardium; ve, ventricle; vp, venous plexus.