Expression of a recombinant dystrophin in mdx mice using adenovirus vector

Genetic deficiencies may be compensated by delivery of the appropriate gene to the affected tissue(s) by somatic gene transfer. In this study, recombinant adenoviruses (defective for replication) carrying a cDNA coding for a truncated dystrophin or 'minidystrophin' (Ad.dys), associated to adenoviruses carrying a beta-galactosidase reporter gene (Ad.beta gal), were administered locally to evaluate the biochemical correction of the genetic defect in mdx mice mutants. Both genes were placed under the control of muscle specific regulatory elements. Two weeks after a single intramuscular injection of Ad.dys, injected muscles showed a significant increase in the percentage of dystrophin positive fibres when compared to muscles either untreated or injected with Ad.beta gal only. Intramuscular injection of the adenoviral expression vectors elicited a local deleterious effect on muscle morphology, rarefaction of myofibres at the site of injection, calcifications and fibrosis were much more marked in comparison to control muscles injected with vehicle. beta-galactosidase was exclusively expressed within myofibres in a segmental fashion. Regional co-localization of beta-galactosidase and dystrophin expression gives further support to the demonstration of adenoviral induced expression of the recombinant genes.