Neural Crest Cell Migration and Derivatives

The neural crest is a transient, migratory cell population that arises at the border of the neural plate and delaminates from the dorsal neural folds as the tube closes. Often described as a fourth germ layer because of its remarkable range of fates, neural crest cells migrate along defined pathways to build much of the peripheral and autonomic nervous system as well as pigment cells and many craniofacial structures.

Definition

Neural crest cell migration and derivatives describes the formation of neural crest cells at the neural plate border, their delamination from the dorsal neural tube via an epithelial-to-mesenchymal transition, their migration along defined pathways, and the diverse neuronal, glial, pigment, and craniofacial cell types they generate.

Scope

The entry covers neural crest induction at the neural plate border, the epithelial-to-mesenchymal transition and delamination that release the cells, their migration along distinct routes, and the axial-level-dependent derivatives they form. It is an educational reference to developmental anatomy, not clinical guidance.

Key concepts

• Neural plate border specification
• Epithelial-to-mesenchymal transition
• Delamination and migration pathways
• Cranial, vagal, trunk, and sacral neural crest
• Neural crest gene regulatory network
• Dorsal root and autonomic ganglia
• Melanocytes and craniofacial mesenchyme
• Collective cell migration

Mechanisms

Signals at the boundary between neural and non-neural ectoderm induce a neural plate border identity, and a hierarchy of border and neural crest specifier genes assembles a gene regulatory network that confers neural crest identity. As the neural folds fuse, prospective crest cells undergo an epithelial-to-mesenchymal transition, losing apical adhesion and delaminating from the dorsal tube. They then migrate along defined pathways, in part as coordinated collectives, with their routes and final fates depending on the axial level of origin. Cranial crest contributes craniofacial bone, cartilage, and connective tissue along with cranial ganglia; vagal and sacral crest colonize the gut to form the enteric nervous system; and trunk crest forms dorsal root and sympathetic ganglia, Schwann cells, and melanocytes.

Clinical relevance

Because the neural crest contributes to so many tissues, disturbances of its development are associated with a heterogeneous group of conditions affecting craniofacial, cardiac, pigment, and enteric structures, sometimes grouped under the term neurocristopathies. This entry describes the underlying developmental biology for reference and education and is not a basis for individual diagnosis or treatment.

History

The neural crest was first described in the nineteenth century, and twentieth-century experimental embryology, notably quail-chick chimera fate mapping, established the breadth of its derivatives and the dependence of fate on axial level. More recent molecular work reconstructed the gene regulatory network that specifies neural crest identity, as synthesised in modern reviews.

Debates

How multipotent are individual neural crest cells?

Whether premigratory and migrating neural crest cells are broadly multipotent or largely fate-restricted has been debated, with lineage-tracing and clonal studies offering evidence on both sides and refining the picture over time.

Key figures

• Nicole Le Douarin
• Marianne Bronner
• Roberto Mayor

Seminal works

• mayor-2013
• simoes-costa-2015
• betancur-2010

Frequently asked questions

Why is the neural crest sometimes called a fourth germ layer?

Because it gives rise to an unusually wide range of cell types spanning derivatives normally attributed to different germ layers, including peripheral neurons and glia, pigment cells, and craniofacial bone and cartilage.

Do all neural crest cells make the same structures?

No. Fate depends largely on the axial level of origin; cranial crest forms craniofacial structures and cranial ganglia, vagal and sacral crest form the enteric nervous system, and trunk crest forms dorsal root and sympathetic ganglia, Schwann cells, and melanocytes.