A HOMOLOG OF DYSTROPHIN IS EXPRESSED AT THE NEUROMUSCULAR-JUNCTIONS OF NORMAL INDIVIDUALS AND DMD PATIENTS, AND OF NORMAL AND MDX MICE - IMMUNOLOGICAL EVIDENCE

Polyclonal and monoclonal antibodies, which recognize different regions and epitopes of the dystrophin molecule, bind to a protein of M(r) 400 000 which is present in extracts of mdx muscle from regions which contain neuromuscular junctions (NMJ) and is absent from those which do not. This NMJ-associated homologue of dystrophin has at least 2 epitopes which are different to the usual Xp21 form of dystrophin expressed along the sarcolemma of muscle fibres in normal muscles. This protein is also expressed at the NMJ of a DMD patient who lacks the first 52 exons on the Xp21 dystrophin gene and it must therefore be translated from a different gene transcript.