Specification of zebrafish neural crest.

Analysis of neural crest cells in wild-type zebrafish and in isolated mutants has complemented studies in other organisms and has led to a greater understanding of the processes of cell fate and regional specification. Analysis of pigment cell development suggests that neural crest cell fate specification results from a combination of intrinsic cues such as differential expression of transcription factors and external factors such as the Wnts. Whether this model can be generalized to accommodate other neural crest cell fates remains an active area of research. Regional specification of neural crest appears to be coordinated by similar combinations of internal factors such as the hox genes, and extrinsic cues such as retinoic acid and endothelins. There is still a wealth of zebrafish mutations whose molecular bases remain unknown, and it is likely that the revelation of the underlying genes will both broaden and alter our understanding of specification within the neural crest.