Restriction of neural crest cell fate in the trunk of the embryonic zebrafish.

To learn when cell fate differences first arise in the zebrafish trunk neural crest, individual premigratory crest cells were labeled intracellularly with fluorescent vital dyes, followed in living embryos and complete lineages recorded. Although some of the earliest cells to migrate produced derivatives of multiple phenotypes, most zebrafish trunk neural crest cells appear to be lineage-restricted, generating type-restricted precursors that produce single kinds of derivatives. Further, cells that produce derivatives of multiple phenotypes appear to do so by first generating type-restricted precursors. Among the various types of derivatives, sensory and sympathetic cells arise only from early migrating crest cells. Some type-restricted precursors display cell-type-specific characteristics while still migrating. Taken together, these observations suggest that some trunk neural crest cells are specified before reaching their final locations.