Cell adhesion molecules during Xenopus myogenesis.

Muscle development is characterized by several cell-recognition events such as the fusion of primary and secondary myoblasts and synaptogenesis. Cell surface adhesion receptors are probably playing an important role in determining the correct evolution of these processes. In this paper we examine the expression of three cell adhesion molecules, N-CAM, N-cadherin and EP-cadherin, during Xenopus larval muscle development. Their differential distribution suggests a specific role for each of these molecules during myogenesis. N-CAM might control the fusion of primary myoblasts as its expression is particularly high in these cells and decreases sharply in myotubes. EP-cadherin is present both in differentiated myotubes and myoblasts and could be involved in secondary myoblast fusion. While N-cadherin appears only much later during muscle differentiation.