Fig. 1

The Dll4in3 enhancer directs arterial-specific expression in both transgenic mice and zebrafish. (A) Schematic representation of mouse Dll4 gene (Upper) and Dll4in3hsp transgene (Lower). (B–L) The Dll4in3hsp transgene directs arterial-specific expression. Representative transgenic whole-mount embryos (B and D) and transverse sections (C and E) show reporter gene expression (X-Gal staining, blue) in dorsal aorta (da) but not the cardinal vein (cv). (Scale bar: 50 μm.) At E15, X-Gal staining is detected in arterial (a) but not venous (v) cells in whole-mount embryo (F and G), yolk sac (H), and transverse section (I). E15 transverse paraffin sections showed overlapping expression of X-gal staining (J), or β-gal (K and L) with the arterial markers Neuropilin1 (Nrp1) (J2) and Ephrin B2 (Efnb2) (K22). Expression of the venous marker Endomucin (Emcn) did not overlap that of the reporter gene (L22). (Scale bar: 10 μm.) (M–O) The mouse Dll4in3 transgene (M) directs arterial-specific expression of the GFP reporter gene in transgenic zebrafish line tg(Dll4in3:GFP) to dorsal aorta (da) and intersegmental arteries (ISA) but not the posterior cardinal vein (pcv) or intersegmental veins (ISVe)(N and O). (P–U) The zebrafish Dll4in3 transgene (P) directs arterial-specific expression in transgenic mice in arteries but not veins in whole-mount embryos (Q and S) and transverse sections (R and T). No overlap was seen with the venous marker Emcn (U). See also Fig. S1.