Adhesion and junction molecules in embryonic and adult lens cell differentiation.

The expression of the neural cell adhesion molecule NCAM and its polysialic acid (PSA) moiety was documented during embryonic development and adult differentiation of chicken lens cells. In both the embryo and adult, NCAM is predominantly found in the epithelium and the zone of young elongating cells of the annular pad. NCAM abundance drops markedly in the cortical fibers and is further reduced in the lens nucleus. Epithelial cell NCAM is more highly poly-sialylated in the adult than in the embryonic lens. Three isoforms of NCAM at 180, 140, and 120 kDa were detected in the lens and predominantly associated with the unit membrane-enriched plasma membranes of fiber cells. The distribution of NCAM relative to MP26 and the adherence junction-associated glycoprotein N-cadherin suggests that NCAM could influence the formation of fiber cell gap junctions and adherence junctions.