Figure 1.

y11 mutants have defects in angiogenesis and vascular morphogenesis. (A,B) TUNEL staining of the trunks of 24 hpf wild type (A) and y11 mutant (B) animals, low background in wild type animals and substantially increased staining in the developing axial vessels of y11 mutants (arrows). (C–I) Two-photon images of Tg(fli1:EGFP)^y1 transgenic wild type or y11 mutant animals at 24 hpf (C–G) and 48 hpf (H,I). Wild type siblings (C,F,H) have intersegmental vessel sprouts (arrows in C) and properly lumenized axial vessels (arrowheads in F) at 24 hpf. Intersegmental vessels have formed a lumenized, functional vascular network by 48 hpf (H). In y11 mutants (D,G,I) intersegmental vessel sprouts are absent at 24 hpf (D) and axial vessels fail to undergo proper tubular morphogenesis (G). Intersegmental vessels are similarly absent in etsrp morphants at 24 hpf (E). By 48 hpf y11 mutants have aberrant intersegmental vessel sprouts that are not fully extended and have some branching and pathfinding errors (I). (J,K) Electron microscopy of 24 hpf zebrafish shows defects in vascular morphogenesis in y11 mutants. Wild type siblings have normal single-cell thick endothelial epithelium (arrows) around the dorsal aorta (J), but endothelial cells in y11 mutants do not form a proper epithelium (K). Anterior is to the left, dorsal up in all panels. Rostral is to the left and dorsal is up in panels A–I. Scale bars = 200 μm (A,B), 200 μm (C–E), 50 μm (F,G), 100 μm (H,I), 10 μm (J,K)