Fig. 8

The effect of tnnt2aMO and RGD peptide treatment on the formation of IRV.

(A) Blockage of blood flow by the tnnt2aMO injection into Tg(kdrl:GFP)^s843 embryos led to a collapsed and enlarged phenotype of the DA at 48 hpf, yet did not inhibit the formation of IRV (white arrows). (B) While Fn (red) was tightly aggregated around the IRV in the control embryo at 48 hpf, in the tnnt2a morphant it was loosely deposited around the IRV which extended toward the lateral rather than the ventral side. (C) RGD treatment via microangiography into Tg(kdrl:GFP)^s843 embryos at 1.5 dpf and harvested at 52 hpf showed that antagonizing the Fn function led to stunted IRV formation and retarded steroidogenic cell migration as compared with the BSA injected control embryo, which was confirmed by quantification of the length of IRV in (D) and of the distance between the midline and the tip of migrating interrenal tissue in (E). (D) The length of IRV was checked with confocal Z-stacks covering the full range of IRV growth, and measured from single focal planes displaying the maximal range of ventrally extending IRV. (E) The distance between the midline and the migrating tip of steroidogenic tissue is designated as positive if the tip of migrating cells has not reached the midline, and as negative if the tip has migrated across the midline. Abbreviations: interrenal tissue (IR), dorsal aorta (DA), interrenal vessel (IRV), notochord (NC), posterior cardinal vein (PCV). Scale bar is 50 μM.