(PhysOrg.com) -- Gene therapy is medicine?s rising star with adeno-associated virus (AAV) vectors ? nonpathogenic parvoviruses ? among the most promising supporting actors, due largely to their capability to integrate into transcriptionally silent genomic regions (areas that do not, via RNA polymerases, make a messenger RNA copy of DNA-stored genetic information). That being said, there?s been a downside in assembling AAV vectors into adenoviral (Ad) viral backbones, which are used extensively in genetic research and therapy: They rely on replication (Rep) proteins ? in this study, the Rep 78/68 polypeptide ? which limit viral amplification methodologies.