Figure 5

XDab2 mediates the induction of VEGF by activin-like signaling. (A) RT-PCR analysis revealing that XDab2 MO (40 ng), but not Co MO, inhibits the induction of VEGF gene by CA hALK4 RNA (2 ng) in animal cap tissues. +RT and -RT; control RT-PCR on the whole embryo RNA in the presence or absence of reverse transcriptase. AC, uninjected animal cap cells. Four-cell stage embryos were injected into the animal pole region with a combination of the indicated reagents, and then animal caps isolated at late blastula stages were cultured to stage 20 and subsequently subjected to RT-PCR analysis. (B-E) VEGF gene expression could be reduced by Dab2 depletion but not by its overexpression. (D) XDab2 RNA (2 ng)-injected embryo. (E) hDab2 RNA (2 ng)-injected embryo. (F) The inhibition of activin-like signaling by injection of DN hALK4 (1 ng) decreased VEGF gene expression. (G) The table summarizing the results of Fig. 5B-F. (H-J) The angiogenic defects caused by XDab2 knockdown can be rescued by coexpression of VEGF. Arrows and arrowheads indicate the normal and inhibited ISV, respectively. The amount of injected reagents: 30 ng, Co Mo; 30 ng, XDab2 MO; 1 ng, VEGF mRNA. (K) The graph showing the results of Fig. 5H-J.