Fig. 8. Xdsh-D2 inhibits convergent extension in heterochronic neural plate grafts. (A) Neural plate grafts were prepared by removing the neural ectoderm of stage 11.5 embryos and grafting in animal caps from injected embryos. (B) Grafted GFP expressing animal caps are induced to become neural tissue (Mariani et al., 2001; Ribisi et al., 2000), are integrated into the host embryo, and undergo normal neural morphogenesis as shown by the convergent extension of the posterior portion of a GFP-expressing graft (b'). (C) Dorsal view of embryos with GFP-expressing grafts develop normally and close their neural tubes; GFP expression (c') demonstrates the extent of convergent extension of the graft (n=9 recombinates from three experiments). White arrows indicate the anterior and posterior limits of the GFP-expressing graft. (D,E) Dorsal view of embryos with Xdsh-D2-expressing grafts that fail to close their neural tubes (red arrowheads); GFP fluorescence of the Xdsh-D2 construct (d',e') indicates that the grafts fail to converge and extend (n=14 recombinates from three experiments). (F) Unmanipulated embryos at stage 30 are straight and elongated. (G) Embryos with GFP-expressing grafts are also elongated and straight, although they do display a very subtle dorsal flexure as a result of grafting. (H) Embryos with Xdsh-D2 grafts are elongated but develop with a pronounced dorsal flexure.
