Early induction of the neural crest in Xenopus

R. MAYOR; S. VILLANUEVA; M. AYBAR; A. GLAVIC; G. ACUÑA; C. TRÍBULO; S. M. HONORÉ; F. BASTIDAS; E. RODRIGUEZ

Marriott Copley Place, Boston, MA, USA.

Congreso; Society for Developmental Biology, 62nd annual meeting; 2003

Society for Developmental Biology

The neural crest segregates from the dorsal portion of the neural tube and migrates through the embryo to generate a highly pluripotent cell population, able to generate a variety of cell types. The cellular and molecular mechanisms that control neural crest induction and differentiation are only now beginning to be unraveled. We will present data that support a model of neural crest induction in three steps. We have characterized the first step of neural crest induction as the specification of the entire border of the neural plate as anterior neural fold. This step depends on a gradient concentration of BMP. In the second step additional signals such as Wnts, FGF, and retinoic acid transform the most posterior region of the anterior neural fold into prospective neural crest cells. This transformation corresponds to the posteriorizing signals that works on the neural plate. In this second step the Notch/Delta signaling plays an important role on the specification of the borders of the neural crest territory. The third step, that takes place once the neural tube is closed, requires higher values of BMP, as an inhibition on BMP activity at this step leads to a decreasing in the expression of the neural crest markers. The combination of all these signals at different steps leads to the activation of specific genes in the neural crest cells. We have shown that some of these genes work in the specification of the neural crest (such as Snail), while others work as survival factors (such as Slug, Sox10). A final model where all these extracellular signals and transcription factors are considered will be discussed.