Figure 6

Lysophosphatidic acid (LPA)-mediated activation of Rho signaling inhibits neural crest (NC) delamination in explants and in ovo. (A,B) Treatment of explanted neural primordia with LPA enables flatterning of the epithelioid sheet but virtually inhibits generation of mesenchymal (M) NC (B) when compared to controls (A). (C,D) Y27632 alone promotes vigorous cell delamination (C) and reverts LPA-induced inhibition (D). (E,F,G) Application of control gel (E, left, and F) or of LPA mixed with pluronic gel (E, right and G) dorsal to neural tubes (NTs) in ovo was preceded by unilateral electroporation of green fluorescent protein (GFP)-DNA. (E) Dorsal view of two living embryos. (F,G) Transverse sections. Note emigration of labeled NC cells in (E, left panel) and F (arrows) and lack of emigrating cells in (E, right panel) and (G). (H) Application of LPA mixed with pluronic gel dorsal to NTs reduces NC delamination in ovo opposite both epithelial (ES) and dissociating somites (DS) (*p < 0.05, **p < 0.01). Ctl, control gel. Bar: 70 μM (A-D); 25 μM (F,G).