IN-VIVO MUSCLE GENE-TRANSFER OF FULL-LENGTH DYSTROPHIN WITH AN ADENOVIRAL VECTOR THAT LACKS ALL VIRAL GENES

Duchenne muscular dystrophy (DMD) is an important target for gene tran sfer because of the disease's high frequency and devastating course. T o date, adenoviral vector-mediated gene transfer for DMD has been unav ailable because (1) adenoviral vectors were unable to accommodate the full-length dystrophin cDNA (14 kb); and (2) adenoviral vectors induce d inflammatory reactions in the gene transfer recipient. We addressed both problems with a novel adenoviral vector that contains no viral ge nes and encodes 28.2 kb of foreign DNA including both the full-length dystrophin cDNA with the muscle creatine kinase promoter for transcrip tional control and a lacZ marker gene. This report presents the in viv o expression of dystrophin and beta-galactosidase from this vector in skeletal muscle of the mdx mouse, a mutant mouse that lacks dystrophin . Somatic delivery of the vector by intramuscular injection in 6-day-o ld mice resulted in the expression of full-length, recombinant dystrop hin at the muscle membrane. Dystrophin-associated proteins were restor ed in muscle fibers expressing recombinant dystrophin. Mdx muscle inje cted with our vector showed a decrease in the proportion of fibers wit h nuclei located centrally; centrally placed nuclei in muscle fibers a re characteristic of cycles of degeneration and regeneration suffered by dystrophin-deficient muscle tissue. These results are strong eviden ce that adenoviral vector-mediated full-length dystrophin delivery pro vides substantial somatic function.