Developmental regulation of a cadherin during the differentiation of skeletal myoblasts.

Cadherins are a family of integral membrane glycoproteins which mediate calcium-dependent intercellular adhesion in vertebrate species. Here we present evidence that fusion-competent rat L6 myoblasts express a cadherin (Mr 127 kDa). The levels of this cadherin were found to be developmentally regulated. Maximal levels were expressed prior to fusion. The increase in cadherin levels observed during differentiation was prevented by the differentiation inhibitor, 5-bromo-2'-deoxyuridine. L6 myoblasts grown in the presence of anti-cadherin antibodies exhibited an altered morphology in comparison to control cultures, coupled with decreased myoblast fusion. These data indicate that the developmental regulation of cadherin is part of the program of terminal differentiation of skeletal myoblasts, and that cadherins are involved in the process of myoblast fusion.