ANALYSIS OF DYSTROPHIN IN FAST-TWITCH AND SLOW-TWITCH SKELETAL-MUSCLES FROM MDX AND DY2J MICE AT DIFFERENT AGES

Muscles from mdx, control, and dy2J/dy2J mice at different ages were analyzed for dystrophin in an attempt to relate the chronology of the protein expression with the final phenotypes in regenerated, normal, and dystrophic muscle, respectively. Immunostaining and gold staining of electrophoresis gels were carried out in the investigation. At 5, 25, and 219 days of age, control muscles exhibited dystrophin bands in both the fast‐twitch extensor digitorum longus (EDL) and the slow‐twitch soleus (SOL) muscles. Muscles from the mdx mice at comparable age (8,28, and 217 days)never exhibited bands for dystropin, although titin, nesbulin, myosin, and other protein bands were present at intensities comparable to those in control muscles. The dystrophin band was present in both the EDL and SOL from dy2J/dy2J dystrophic mice. As indicated by the present study, the dystrophin dificiency from mdx tissue is not transient. This suggests that dystrophin is not necessary for the success of mdx muscle regeneration. Copyright © 1990 John Wiley & Sons, Inc.