Chicken embryo lens cultures mimic differentiation in the lens

Embryonic chicken lenses, which had been disrupted by trypsin, were grown in culture. These cultures mimic lens development as it occurred in vivo, forming lens-like structures known as lentoids. Using a variety of techniques including electron microscopic analysis, autoradiography, immunofluorescence, and polyacrylamide gel electrophoresis, it was shown that the lentoid cells had many characteristics in common with the differentiated cells of the intact lens, the elongated fiber cells. These characteristics included a shut off of DNA synthesis, a loss of cell organelles, an increase in cell volume, an increase in δ-crystallin protein, and the development of extensive intercellular junctions. The cultures began as a simple epithelial monolayer but then underwent extensive morphogenesis as they differentiated. This morphogenesis involved three distinctive morphological types which appeared in sequence as an epithelial monolayer of polygonal shaped cells with pavement packing, elongated cells oriented end to end, and the multilayered, multicellular lentoids. These distinct morphological stages of differentiation in culture mimic morphogenesis as it occurs in the lens.