title: Resolving time and space constraints during neural crest formation and delamination.
abstract: A striking feature of neural crest development in vertebrates is that all the specification, delamination, migration, and differentiation steps occur consecutively in distinct areas of the embryo and at different timings of development. The significance and consequences of this partition into clearly separated events are not fully understood yet, but it ought to be related to the necessity of controlling precisely and independently each step, given the wide array of cell types and tissues derived from the neural crest and the long duration of their development spanning almost the entire embryonic life. In this chapter, using the examples of early neural crest induction and delamination, we discuss how time and space constraints influence their development and describe the molecular and cellular responses that are employed by cells to adapt. In the first example, we analyze how cell sorting and cell movements cooperate to allow nascent neural crest cells, which are initially mingled with other neurectodermal progenitors after induction, to segregate from the neural tube and ectoderm populations and settle at the apex of the neural tube prior to migration. In the second example, we examine how cadherins drive the entire process of neural crest segregation from the rest of the neurectoderm by their dual role in mediating first cell sorting and cohesion during specification and later in promoting their delamination. In the third example, we describe how the expression and activity of the transcription factors known to drive epithelium-to-mesenchyme transition (EMT) are regulated timely and spatially by the cellular machinery so that they can alternatively and successively regulate neural crest specification and delamination. In the last example, we briefly tackle the problem of how factors triggering EMT may elicit different cell responses in neural tube and neural crest progenitors.
authors: Laboratoire de Biologie du Développement, Université Pierre et Marie Curie-Paris 6, Paris, France; CNRS, Laboratoire de Biologie du Développement, Paris, France. Electronic address: jean-loup.duband@upmc.fr.
authors: Jean-Loup
authors: JL
authors: Duband
authors: Laboratoire de Biologie du Développement, Université Pierre et Marie Curie-Paris 6, Paris, France; CNRS, Laboratoire de Biologie du Développement, Paris, France.
authors: Alwyn
authors: A
authors: Dady
authors: Laboratoire Matière et Systèmes Complexes, CNRS et Université Denis-Diderot-Paris 7, Paris, France.
authors: Vincent
authors: V
authors: Fleury
mesh_terms: D000818:Animals; D015820:Cadherins / Q000378:metabolism*; D002465:Cell Movement / Q000502:physiology*; D004627:Embryonic Induction / Q000502:physiology*; D058750:Epithelial-Mesenchymal Transition / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental / Q000235:genetics / Q000502:physiology*; D006801:Humans; D009432:Neural Crest / Q000196:embryology*; D013997:Time Factors; D014714:Vertebrates / Q000196:embryology*
chemical_list: D015820:Cadherins
keywords: Cadherins; Core EMT regulatory factors; Delamination; Epithelium-to-mesenchyme transition; Induction; Migration; Neural crest; Sorting