DYSTROPHIN AND DYSTROPHIN-RELATED PROTEIN EXPRESSION IN TORPEDO-MARMORATA ELECTRIC ORGAN

The presence of different dystrophin-related protein forms was investi gated in electric organ as compared to cardiac, white or red skeletal muscles from Torpedo marmorata. Two strategies were followed. First, w e used specific C-terminal dystrophin and dystrophin-related protein m onoclonal antibodies which we characterized in the present study. 400 kDa protein bands were detected in the tissues mentioned above with bo th specific types of antibodies. Second, we produced monoclonal antibo dies raised against a dystrophin-enriched preparation from T. marmorat a electric organ. Western blot and immunofluorescence analyses showed the tissue specificity of T marmorata antibodies and allowed us to cla ssify them as types I, II and III. Vessel walls and neuromuscular junc tions were labeled with T marmorata type II and III antibodies in huma n muscles (skeletal and smooth). Both approaches demonstrated that the T marmorata electric organ contained different proteins related with dystrophin: a dystrophin form, a dystrophin-related protein form and a dystrophin-related protein isoform, homologous to the dystrophin-rela ted protein present in muscle vessel walls and at the neuromuscular ju nctions of human tissues. The presence of dystrophin and dystrophin-re lated protein is finally discussed relative to their functions and org an specificities.