The effect of VEGF on blood vessels and blood cells during Xenopus development

Abstract

Vascular endothelial growth factor (VEGF) is known to play an essential role in vascular development. We have overexpressed VEGF 122 or VEGF 170, which are equivalent to mouse VEGF 120 and VEGF 164, in developing Xenopus embryos. Overexpression of VEGF 170 but not VEGF 122 demonstrated an absence of expression of hematopoietic markers α-globin and GATA-1 but only in the posterior portion of the blood island. Interestingly, strong signals of endothelial markers, msr, fli-1, and tie-2, were detectable in those regions, instead of hematopoietic markers. These results suggested both that injection of VEGF 170 resulted in disturbance of vasculogenesis in the posterior portion of the blood island, with excessive production of endothelial cells at the expense of blood cells, and that the anterior and posterior portions of the VBI may have distinct characteristics.