Fig. 2

Fig. 2 smo mutation causes loss of the aortic bifurcation. (A–C) Transverse section analyses showing normal lumen sizes of the dorsal aorta and the posterior cardinal vein in wild-type embryos (A); single enlarged cardinal vein (B) and collapsed cardinal vein in smo mutants (C). (D) Bar chart depicting perimeter measurements of lumen sizes of the dorsal aorta and the cardinal vein in wild-type embryos and smo mutants. Lumen sizes were measured in 15 transverse sections derived from three wild-type and three smo mutant embryos, respectively. Error bars indicate standard deviation and asterisks indicate statistical significance between wild-type and smo data (P < 0.01). (E–H) In situ hybridization of flk1 at 24 hpf (E, F) and confocal microscopy in Tg(flk1:EGFP) embryos at 48 hpf (G, H) exhibiting loss of the aortic bifurcation and expansion of bilateral cardinal veins in smo mutants (F;H), compared to the normal aortic bifurcation and bilateral cardinal veins in wild-type embryos (E;G). (I, J) Schematics depicting the aortic bifurcation flanked by bilateral cardinal veins in wild-type embryos, compared to enlarged bilateral cardinal veins in smo mutants. Red arrow: aorta. Blue arrow: vein. Yellow arrow: intersomitic vessel. DA: dorsal aorta. LDA: lateral dorsal aorta. acv: anterior cardinal vein. ccv: common cardinal vein. pcv: posterior cardinal vein. LDA′, acv′,ccv′, pcv′: denote the corresponding vessel on the other side of the embryo.