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XB-ART-45533
Dev Biol May 1, 2012; 365 (1): 196-207.

Early neural crest induction requires an initial inhibition of Wnt signals.



Abstract
Neural crest (NC) induction is a long process that continues through gastrula and neurula stages. In order to reveal additional stages of NC induction we performed a series of explants where different known inducing tissues were taken along with the prospective NC. Interestingly the dorso-lateral marginal zone (DLMZ) is only able to promote the expression of a subset of neural plate border (NPB) makers without the presence of specific NC markers. We then analysed the temporal requirement for BMP and Wnt signals for the NPB genes Hairy2a and Dlx5, compared to the expression of neural plate (NP) and NC genes. Although the NP is sensitive to BMP levels at early gastrula stages, Hairy2a/Dlx5 expression is unaffected. Later, the NP becomes insensitive to BMP levels at late gastrulation when NC markers require an inhibition. The NP requires an inhibition of Wnt signals prior to gastrulation, but becomes insensitive during early gastrula stages when Hairy2a/Dlx5 requires an inhibition of Wnt signalling. An increase in Wnt signalling is then important for the switch from NPB to NC at late gastrula stages. In addition to revealing an additional distinct signalling event in NC induction, this work emphasizes the importance of integrating both timing and levels of signalling activity during the patterning of complex tissues such as the vertebrate ectoderm.

PubMed ID: 22394485
PMC ID: PMC3657187
Article link: Dev Biol
Grant support: [+]

Species referenced: Xenopus
Genes referenced: bmp4 dkk1 dlx5 hes4 msx1 nog npb pax3 snai1 snai2 sox2 sox3 zic3

Phenotypes: Xla Wt + Hsa.BMP4 (fig.4.d) [+]

Article Images: [+] show captions
References [+] :
Aybar, Snail precedes slug in the genetic cascade required for the specification and migration of the Xenopus neural crest. 2002, Pubmed, Xenbase