PNA-positive glycoconjugates are negatively correlated with the access of neural crest cells to the gut in chicken embryos.

Neural crest cells give rise to many derivatives, including the neurons and glia of the peripheral nervous system, adrenomedulary cells, and melanocytes, and migrate through precise pathways that differ according to their axial level and/or state of specification. The migratory routes taken by neural crest cells are reported to be regulated by extracellular matrix molecules. We examined the possible influence of glycoconjugates on the establishment of barriers to neural crest access to ventral regions leading to the gut, by labeling stage-16-28 white Leghorn (WL) and Silky (SK) embryos with peanut agglutinin (PNA) at vagal, thoracic, and sacral levels. We observed a transitory expression of glycoconjugates that correlate with a barrier to the entrance of neural crest cells into the gut at the thoracic level, which is not present at vagal and sacral levels. In later stages, neural crest cells of melanocytic lineage were observed entering the gut in embryos of the SK chicken, a mutant with an altered pattern of pigmentation. The ventral regions occupied by melanoblasts in SK embryos were free of PNA labeling, while in WL embryos, in which PNA-positive molecules are strongly expressed, melanoblasts were restricted to peripheral regions. We suggest that PNA-binding glycoconjugates are good molecular marker for barriers that control the access of neural crest cells to the gut.