Fig. 4.

RAR-α is expressed by endothelial cells of the cardinal veins of mouse embryos. Immunohistochemical analysis of mouse embryos for LYVE-1 (a, c: ED 11.5) and RAR-α (b, d: ED 11.5; e: ED 10.5; f: ED 9.5) revealed that RAR-α (b, d, arrowheads) is expressed by/near the endothelial cells of the LYVE-1+ (a, c, arrowheads) cardinal veins and forming jugular lymph sacs of ED 11.5 as well as in/near the cardinal veins of ED 10.5 (e, arrowheads) and ED 9.5 (f, arrowheads) mouse embryos. Two serial sections are shown in a and b. a, b Scale bars = 50 μm; c–f scale bars = 20 μm. Cell nuclei were counterstained with hematoxylin. a = Dorsal aorta; jls = jugular lymph sac; nt = neural tube; v = cardinal vein.