THE EXPRESSION OF B-CADHERIN DURING EMBRYONIC CHICK DEVELOPMENT

Cadherins compose a family of calcium-dependent cell adhesion molecules that are involved in the segregation of differentiating tissues during development. Each cadherin has a unique spatial and temporal pattern of expression. As has been observed for other cadherins, B-cadherin, when expressed in mouse L929 fibroblasts, confers upon them a calcium-dependent cell aggregation activity. A monoclonal antibody to B-cadherin was isolated and used to determine the pattern of expression of B-cadherin in the developing chick embryo. Antibody staining and in situ hybridization reveal that B-cadherin protein and mRNA are found in diverse epithelia derived from each of the three primary germ layers, where their expression is strikingly regulated during differentiation. In some instances, the regional distribution of B-cadherin within a tissue reflects the distinct functional regions of the tissue. Patterns of staining are similar to, but distinct from, those seen with anti-LCAM antibodies. Although there are many examples where B-cadherin and LCAM are coexpressed, there are also distinctive regional differences. © 1994 by Academic Press, Inc.