Neural induction in Xenopus.

Although induction of neural tissue in vertebrates has been recognized since the experiments of Spemann and Mangold seventy years ago, only recently has the phenomenon been put onto a molecular footing. Three molecules, noggin, follistatin and fibroblast growth factor, have been shown to have neuralizing activity in various assays. These assays for neural induction and the molecular mechanisms for the action of neural inducers are reviewed here.