RABBIT BRAIN AND MUSCLE ISOFORMS CONTAINING THE CARBOXY-TERMINAL DOMAIN OF 427 KDA SKELETAL-MUSCLE DYSTROPHIN EXHIBIT SIMILAR BIOCHEMICAL-PROPERTIES

The membrane cytoskeletal component dystrophin, which is the protein p roduct of the human Duchenne muscular dystrophy gene, exists in manifo ld isoforms. Using immunoblot analysis with an antibody to the carboxy -terminal domain of the 427 kDa skeletal muscle dystrophin, we investi gated the membrane cytoskeletal properties of dystrophin isoforms from rabbit skeletal muscle, heart and brain. All isoforms identified, inc luding the abundant brain isoform Dp116 which lacks the amino-terminal actin-binding domain of 427 kDa dystrophin, exhibited similar biochem ical properties, i.e. insolubility in non-ionic detergent but extracti on from the membrane with alkaline solutions. In muscle, beta-dystrogl ycan was found to be more tightly associated with dystrophin than alph a-sarcoglycan. These findings agree with the proposed structure of ide ntified muscle and brain dystrophin isoforms and are also consistent w ith the current model of the dystrophin-glycoprotein complex. (C) 1997 Elsevier Science Ireland Ltd.