Fig. 1

Fig. 1

The SIVP originates from the PCV. (A) Lateral view of a Tg(fli:EGFP)^y1 zebrafish embryo at 4 dpf. The SIVP is located on the surface of the yolk. (B) In situ hybridization with gata6 shows the position of the endoderm/gut (white arrowheads) in comparison to the outer SIVP basket (black arrowheads) at 3 dpf. (C) Analogous mouse omphalomesenteric vessels (vitelline veins) of the yolk sac of an E12.5 mouse embryo are indicated by white arrowheads. (D–I′) Single images taken from a time-lapse series highlight steps in the genesis of the SIVP. Images are shown for the left side of the embryo (D–E). At around 28 hpf, few cells start sprouting from the vein (white arrows). (F) At 29 hpf, the sprouts start elongating on the yolk ball (white arrows). (G–I) From 31 to 34.5 hpf, the SIVP continues to grow ventrally. (D′–I′ Enlargements of embryos in D–I. (J–L) Schematics corresponding to specific time-lapse images (D′, F′, H′) that clarify the origin of SIVP vessels. (M–N) 3D images of the developing SIVP show sprouts emanating from the vein (yellow arrowheads). Scale bars represent 100 µm.