DEVELOPMENTAL-CHANGES IN GLYCOCONJUGATE COMPOSITION DURING CHICK LENSMORPHOGENESIS

The following lectins: Con A, WGA, sWGA, PNA, RCA and UEA were used to study developmental changes in the expression of glycoconjugates duri ng chicken lens morphogenesis. Con A, WGA, sWGA binding epitopes were observed in the lens placode and vesicle. Once the fiber mass was form ed, the glycoconjugates were mainly found at the epithelial-fiber-cell junction, on epithelial cell membranes but only weakly on fiber-cell membranes. The PNA reaction was restricted to the apical surface of ce lls of the lens placode and vesicle and to the epithelial-liber juncti on throughout the rest of lens development. The RCA reaction was mainl y localized to the apical plasma membrane and moderately at the latera l plasma membrane of cells of the lens placode and vesicle and maintai ned this staining pattern in the lens epithelial cell during the progr essive development of lens. UEA binding was initially localized along the posterior elongating cells of the lens vesicle, and then expressed in both epithelial and fiber cells. Subsequently UEA binding was rest ricted to the epithelium and central fiber mass. The extensive distrib ution of glycoconjugates on the surface of the invaginating placode ce lls suggests a role during invagination and subsequent detachment of t he placode from the surface ectoderm. The capsule was labelled by Con A, WGA, sWGA, RCA and PNA but not by UEA. The posterior capsule was mo re intensely reactive with Con A, RCA and PNA than the anterior capsul e. (C) 1996 Academic Press Limited