It is generally assumed that in amphibian embryos neural crest cells migrate dorsally, where they form the mesenchyme of the dorsal fin, laterally (between somites and epidermis), where they give rise to pigment cells, and ventromedially (between somites and neural tube), where they form the elements of the peripheral nervous system. While there is agreement about the crest migratory routes in ...

Teeth were lost in birds 70-80 million years ago. Current thinking holds that it is the avian cranial neural crest-derived mesenchyme that has lost odontogenic capacity, whereas the oral epithelium retains the signaling properties required to induce odontogenesis. To investigate the odontogenic capacity of ectomesenchyme, we have used neural tube transplantations from mice to chick embryos to r...

The timing and pattern of cranial neural crest cell emergence and migration in the Mexican axolotl, Ambystoma mexicanum, are assessed using scanning electron microscopy (SEM). Cranial neural crest cells emerge and begin to migrate at the time of neural fold closure and soon form three distinct streams. The most anterior (mandibular) stream emerges first, at the level of the mesencephalon. Cells...

The neural crest is a transient embryonic structure whose cells migrate extensively before giving rise to a variety of differentiated cell types. Both intrinsic cell lineage information and environmental cues are thought to play a role in determining the fate of these cells. Early in development, these cells can be divided into distinct populations based on their axial level of origin. Cranial ...

In the developing vertebrate nervous system, both neural crest and sensory neurons form at the boundary between non-neural ectoderm and the neural plate. From an in situ hybridization based expression analysis screen, we have identified a novel zebrafish mutation, narrowminded (nrd), which reduces the number of early neural crest cells and eliminates Rohon-Beard (RB) sensory neurons. Mosaic ana...

The neural crest is a uniquely vertebrate cell type that gives rise to much of the craniofacial skeleton, pigment cells and peripheral nervous system, yet its specification and diversification during embryogenesis are poorly understood. Zebrafish homozygous for the lockjaw (low) mutation show defects in all of these derivatives and we show that low (allelic with montblanc) encodes a zebrafish t...

We have determined the pathways taken by the trunk neural crest of quail and examined the parameters that control these patterns of dispersion. Using antibodies that recognize migratory neural crest cells (HNK-1), we have found that the crest cells take three primary pathways: (1) between the ectoderm and somites, (2) within the intersomitic space and (3) through the anterior somite along the b...

The neural crest is a migratory population of cells that produces many diverse structures within the embryo. Trunk neural crest cells give rise to such structures as the dorsal root ganglia (DRG) and sympathetic ganglia (SG), which form in a metameric pattern along the anterior-posterior axis of the embryo. While static analyses have provided invaluable information concerning the development of...