Hemidesmosome formation by embryonic chick corneal epithelium in vitro.

This study was undertaken in order to determine whether 15-day embryonic chick corneal epithelial cells can form hemidesmosomes when cultured on a variety of substrata. It was found that hemidesmosomes were formed on gelatin films, hydrated collagen gels, lens capsule, scraped corneal stroma, matrix produced by corneal endothelial cells and untreated tissue culture plastic. Hemidesmosomes were found after 5 days in cultures produced from either dissociated epithelial cells or whole epithelial explants. Hemidesmosomes occurred both singly and in groups and their morphology varied between well-defined structures with attachment plaques, sub-basal dense plates and connections to intracellular filamentous networks, and more rudimentary forms. The presence of extracellular material was often associated with the hemidesmosomes, although it was also possible to find hemidesmosomes where this material was absent. This work suggests that, in the embryonic chick cornea, extracellular structures such as anchoring filaments and anchoring fibres often associated with mature hemidesmosomes are not essential for hemidesmosome formation.