The neural crest (NC) is a population of migratory cells that originates at the edge of the neural plate and differentiates into many cell types,including neurons and pigment cells. NC induction in Xenopus depends on signalling through the canonical Wnt and FGF signalling pathways - but do these two pathways interact during NC induction or function independently? On , Jean-Pierre Saint-Jeannet and co-workers report that Fgf8a induces the NC indirectly by activating Wnt8. The researchers show that NC induction by Fgf8a requires active canonical Wnt signalling, whereas Wnt8 can induce NC independently of Fgf8a. Moreover, they demonstrate that Fgf8a is a potent inducer of Wnt8 in both explant culture and whole embryos, and is required for the expression of Wnt8 adjacent to the NC-forming region. These findings solve the riddle of the link between Wnt and FGF signalling by showing that they are part of the same NC induction cascade and that their interaction is required for proper NC specification.
