Fig. 1.

Vascular smooth muscle cells associate with the zebrafish dorsal aorta. (A) Camera lucida drawing of a 2 dpf zebrafish embryo (Kimmel et al., 1995), with the magnified red boxed region shown in B and blue boxed region imaged in C-F. (B) Schematic (‘cut-away’) diagram showing the anatomy of the zebrafish trunk and its blood vessels at approximately 2 days post-fertilization. Trunk circulation flows through the dorsal aorta (DA), posterior cardinal vein (PCV) and intersegmental arteries (ISA) and intersegmental veins (ISV). The vessels are shown relative to adjacent tissues and structures in the mid-trunk including the gut (G), notochord (N), neural tube (NT), left pronephric duct (P), dermamyotomes (D), myotomes (M) and sclerotomes (S). (C-F) Representative confocal images of the dorsal aorta in Tg(tagln:egfp), Tg(kdrl:mCherryCAAX) double transgenic zebrafish at 1 dpf (C), 3 dpf (D), 5 dpf (E), or 7 dpf (F), with red fluorescent vascular endothelium and green fluorescent vSMCs, showing accumulation of vSMCs on the dorsal aorta. (G) Quantification of vSMC accumulation on the first 6-somite segments of the dorsal aorta at 1-7 dpf. Values are mean±s.e.m.; n=5 fish. (H-J) Vascular smooth muscle cell investment of the DA was confirmed by electron microscopy. Representative images of the dorsal aorta wall at 3 dpf (H), 7 dpf (I) and 14 dpf (J) are shown. ECs and vSMCs are pseudo-colored red and green, respectively. Panel B is adapted from Isogai et al. (2003). Scale bar: 50 µm (C-F).