XB-ART-47925Wiley Interdiscip Rev Dev Biol March 1, 2013; 2 (2): 247-59.
Signaling and transcriptional regulation in neural crest specification and migration: lessons from xenopus embryos.
The neural crest is a population of highly migratory and multipotent cells, which arises from the border of the neural plate in vertebrate embryos. In the last few years, the molecular actors of neural crest early development have been intensively studied, notably by using the frog embryo, as a prime model for the analysis of the earliest embryonic inductions. In addition, tremendous progress has been made in understanding the molecular and cellular basis of Xenopus cranial neural crest migration, by combining in vitro and in vivo analysis. In this review, we examine how the action of previously known neural crest-inducing signals [bone morphogenetic protein (BMP), wingless-int (Wnt), fibroblast growth factor (FGF)] is controlled by newly discovered modulators during early neural plate border patterning and neural crest specification. This regulation controls the induction of key transcription factors that cooperate to pattern the premigratory neural crest progenitors. These data are discussed in the perspective of the gene regulatory network that controls neural and neural crest patterning. We then address recent findings on noncanonical Wnt signaling regulation, cell polarization, and collective cell migration which highlight how cranial neural crest cells populate their target tissue, the branchial arches, in vivo. More than ever, the neural crest stands as a powerful and attractive model to decipher complex vertebrate regulatory circuits in vivo.
PubMed ID: 24009035
Article link: Wiley Interdiscip Rev Dev Biol
Species referenced: Xenopus laevis
Genes referenced: acta4 adam33 bmp4 cdc42 cdh11 cxcr4 efnb2 foxd3 gbx2.1 hes4 kremen1 lrig3 meis3 msx1 myc nrarp otx2 pax3 pax7 plxna1 ptk7 rac1 rho rhoj rhou sdc4 snai2 snw1 sox10 stat3.1 tfap2a twist1 wnt1 wnt11b wnt3a wnt7b zic1
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|F I G U R E 1 | Main steps of neural crest development in Xenopus embryos. The steps of neural crest formation are described during gastrulation, neurulation, and organogenesis. For each step, a characteristic marker expression pattern is shown. Pax3, dorsal view of a stage 14 Xenopus laevis embryo; snail2, dorsal view of a stage 18 neurula; sox10, dorsal view of a stage 22 tailbud embryo; melanocytes, one of the neural crest derivatives, side view of a tadpole. All dorsal views are shown with the anterior to the front.|
|F I G U R E 2 | Initial ectoderm patterning is followed by multiple interactions that progressively define the neural crest and trigger its migration. (a) Scheme of ectoderm regionalization at the end of gastrulation. (b) Main signals and transcription factors implicated in neural border induction (during gastrulation), neural border stabilization (end of gastrulation, early neurulation); neural crest proliferation and specification (neurulation). Main characteristics of neural crest migration, as defined in Xenopus cranial neural crest, during organogenesis. See text for details. The control of EMT by neural crest specifiers and neural crest differentiation are not detailed in this review.|
|F I G U R E 3 | Cranial neural crest migration and cartilage differentiation in Xenopus embryos. (a) Cranial neural crest cells migrate anteriorly in the embryos, forming three main streams of migration: the mandibular (MA), hyoid (HY), and branchial streams (BR). Scheme drawn after sox10 expression in a stage 22 embryo. (b) Cells from these streams differentiate into head skeleton elements: Meckel’s cartilage (ME), ceratohyal cartilage (CE), branchial cartilage (BR), basihyal cartilage (BA). Scheme drawn after an alcian blue-stained preparation of the cranial and ventral cartilage from a stage 45 embryo.|