Figure 4

The expression of sox7 in the PCV is upregulated in sox18 mutants, but not in sox18 morphants. (A) Representative images of sox7 ISH on embryos at around 26 hpf derived from matings of sox18^sa12315 heterozygotes in the Tg(lyve1b:DsRed) line. Higher magnifications of the trunk region are shown below the full size images. Compared to wt embryos, the sox7 ISH signal in the PCV is elevated in the great majority of sox18^−/− homozygotes and, to a lesser extent, in sox18^+/− heterozygotes. Numbers in each image state the number of embryos with the reported phenotype over the total analyzed embryos in one representative experiment. Lateral views, anterior to the left. Pictures were taken at 40× and 63× magnification, for lower and higher magnification images respectively. (B) Left, representative ImageJ-modified images, used to perform the quantification of the sox7 ISH signal in the PCV and the DA (as described in Materials and Methods) on 26 hpf wt (+/+), sox18^sa12315 heterozygotes (+/−) or homozygous mutants (−/−). The graph on the right shows the calculated PCV/DA ratio in each embryo; embryos are grouped based on their genotypes: mean values and SEM are indicated. (C) The same analysis was performed on sox7 ISH of sox18 morphants and control embryos, as shown in Figure S6. The calculated PCV/DA ratio of each embryo is shown in the graph; mean values and SEM for std-MO injected embryos and sox18 morphants are indicated. n = number of embryos, ** = p < 0.01; DA = dorsal aorta; PCV = posterior cardinal vein. The analysis was also repeated on ISHs of sox18^sa12315 mutants in the Tg(fli1a:EGFP)^y1 reporter line with similar results. ISH experiments on sox18^sa12315 mutants were repeated at least three times. Data shown in A and B were generated on different clutches of embryos.