Localization of keratin in the cells of the cornea in aphakia and normal mouse embryos

Abnormal lens morphogenesis in the aphakia mutant in the mouse often results in a club-shaped elongated 'lens' that remains attached to the surface epithelium by a persistent connecting stalk, which is partially solid and partially cystic. Usually, the cells are continuous with the surface epithelium of the cornea and also with the cuboidal cells lining the corneal inner surface. Immunofluorescence with keratin antiserum not only gave positive reactions with the corneal epithelial cells, but also with many cells of the lens stalk, including its cysts, and with islands of cells on the inside of the cornea. These keratin-containing 'endothelial' cells may be the product of metaplasia of the endothelium into epithelium-like cells. Alternatively, they may also be the result of abnormal migration of epithelial cells into the eye or of abnormal differentiation of neural crest cells.