Recombinant AAV structures. A. In wild-type AAV, the rep region encodes products required for AAV DNA replication. The lip and cap regions encode the virion capsid proteins. The internal terminal repeats (ITR) are required in cis for AAV packaging and integration into host DNA. B. AAV-β2AR/EGFP represents the complete recombinant vector with tandem β2AR and EGFP cassettes driven by separate CMV promoters.