Developmental Changes in Glycoconjugate Composition During Chick Lens Morphogenesis

Abstract

The following lectins: Con A, WGA, sWGA, PNA, RCA and UEA were used to study developmental changes in the expression of glycoconjugates during chicken lens morphogenesis. Con A, WGA, sWGA binding epitopes were observed in the lens placode and vesicle. Once the fiber mass was formed, 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 cells of the lens placode and vesicle and to the epithelial–fiber junction throughout the rest of lens development. The RCA reaction was mainly localized to the apical plasma membrane and moderately at the lateral plasma membrane of cells of the lens placode and vesicle and maintained this staining pattern in the lens epithelial cell during the progressive 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 restricted to the epithelium and central fiber mass. The extensive distribution of glycoconjugates on the surface of the invaginating placode cells suggests a role during invagination and subsequent detachment of the 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 more intensely reactive with Con A, RCA and PNA than the anterior capsule.