Fig. 6. Blocking vessel formation leads to muscle fusion. (A-D) Dorsal views of wings from E8 chick embryos, which have undergone ink injection before fixation in order to visualize vessel organization. PBS bead implantation at E6 does not modify vessel assembly (B) as compared with the non-grafted left wing (A). sFLT1 bead implantation locally inhibits vessel formation (D) compared with the control left wing (C). (E-H) Transverse sections of sFLT1-treated right wings (F,H) and control left wings (E,G) were hybridized with the MyoD probe in order to visualize muscle organization. (G,H) High magnification of E,F, respectively. The EMU and EDC, two dorsal muscles, are cleaved in control wings, whereas they are fused in sFLT1-treated wings. EMU, extensor metacarpi ulnans; EDC, extensor, digitorum communis; u, ulna; r, radius.