Expression patterns of the cadherin 5 and aquaporin 8. Anterior is to the left in all panels. (A-D) cdh5 expression; (E-H) aqp8 expression. (A) The 15-somite stage. cdh5 mRNA is expressed in 2 distinct anterior (arrow) and middle/posterior (arrowhead) domains within lateral mesoderm. (B) The 26-hpf stage. cdh5 mRNA is expressed in all vascular endothelial cells of axial, intersegmental, and head vessels. (C) The 52-hpf stage, lateral view. cdh5 mRNA is localized to multiple head vessels, aortic arches (aa), pectoral fin bud (fb) vessel, heart (h) endocardium, the common cardinal vein (ccv), the cardinal vein plexus region at the tail (pl), posterior intersegmental vessels, and the dorsal longitudinal anastomotic vessel (dlav). (D) The 52-hpf stage, dorsal view. cdh5 mRNA is expressed in a group of cells within the diencephalon (arrowhead). Inset, ventral view of heart area. cdh5 is expressed in heart endocardium. (E) The 15-somite stage. aqp8 mRNA is expressed within lateral mesoderm in the posterior half on embryo (arrowhead). (F) The 26-hpf stage. aqp8 mRNA is localized to the dorsal aorta, cardinal vein plexus region, and intersegmental vessels. (G) The 36-hpf stage. aqp8 is expressed in the posterior part of the dorsal aorta, intersegmental vessels, the dorsal longitudinal anastomotic vessel (dlav), the cardinal vein plexus region (pl), and heart endocardium. (H) The 72-hpf stage. aqp8 is expressed in the dorsal longitudinal anastomotic vessel (dlav), the pectoral finbud vessel (fb), and faintly in the posterior intersegmental vessels.