Clonal analysis of the avian neural crest: migration and maturation of mixed neural crest clones injected into host chicken embryos.

Quail neural crest cells were grown in vitro at clonal density for 7 to 10 days. Mixed neural crest colonies and clones (containing both pigmented and unpigmented cells) were implanted into the trunk region of 2 1/2-day-old host chicken embryos by a previously described injection technique (Bronner and Cohen '79). Here we describe the migratory behavior and subsequent phenotypic expression of the injected cells. Unpigmented cells and pigmented cells both migrated along the ventral neural crest pathway; there were, however, some differences in migratory behavior between the two cell types. After 3 days in vivo, unpigmented quail neural crest cells contributed to the sympathetic ganglion, adrenal medulla, and/or aortic plexus in the host. Many of the unpigmented cells became catecholamine-containing neuroblasts. Unpigmented cells were never observed in the gonads or the gut, but localized only in regions normally populated by trunk neural crest precursors to neurons and supportive cells. Melanocytes derived from the same precursor, however, were often found in the gonads or gut, in addition to normal neural crest locations in the trunk. These results demonstrate that quail neural crest cells grown in tissue culture for 7 days or more retain the ability to migrate and contribute to normal neural crest structures when placed in the embryonic environment. Under the conditions described, a single neural crest cell gave rise to daughter cells expressing the melanotic phenotype (detected in tissue culture) and adrenergic phenotypes (detected after injection in vivo). This demonstrates that at least some single cells of the premigratory crest in the trunk region are pluripotent.