Fig. 3

sox7 mutants develop a circulatory short-loop phenotype. (A) sox7^hu5626 kdrl:eGFP;gata1:dsRed mutants at 2.5dpf with shunt formation resulting in a circulatory short-loop (middle and right panel) in contrast to normal circulation in sox7^hu5626 siblings (left panel). Middle panel depicts ectopic connection between LDA and PHS, right panel between LDA and CCV. Lower panel depicts only gata1:dsRed with detailed schematic representation of blood flow. CCV, common cardinal vein; LDA, lateral dorsal aorta; PHS, primary head sinus; VA, ventral aorta. (B) Schematic representation of normal blood flow in wild-type embryos compared with the short-circuit in sox7^hu5626 mutants at 2.5dpf. Dashed circles highlight the position of the heart. (A,B) Lines depict blood flow in arteries (red) and veins (blue). (C) Stills of time-lapse movies of kdrl:eGFP-positive sox7 mutant and sibling at the time point of ectopic connection formation (see supplementary material Movies 3 and 4). ECs of the LDA (outlined by red lines) connect to ECs of the CCV (outlined by blue lines) in the sox7 mutant at 26hpf (yellow arrow). (D) Quantification of the phenotypes in 3dpf sox7^hu5626;sox18^hu10320 loss-of-function embryos. All sox7^hu5626;sox18^hu10320 double homozygous mutants have a short-loop of circulation and shunts between DA and PCV, whereas sox7^/sox18^+/+ and sox7^/sox18^+/ embryos have no shunts between DA and PCV. The remaining, non-shown genotypic combinations of sox7;sox18 embryos all have 100% wild-type phenotype. Bars show percentages of embryos of a representative experiment (total of 77 embryos). (E) Hematoxylin and Eosin stained transverse (left panel) and sagittal (right panel) cross-sections of trunks of 2dpf sox7^hu5626 siblings (top) and homozygous mutants (bottom) showing normal DA-PCV segregation in both siblings and mutants (arrows).