AAV DJ/8-Cre

In the past decade, adeno-associated virus (AAV) has transformed from a gene transfer vector to a clinically viable therapeutic candidate. Discovered as a contaminant in adenoviral preparations in the mid-1960s, AAV initially failed to attract much clinical attention due to its complete lack of pathogenicity. AAV is helper-dependent, meaning that its replication depends on the presence of a helper virus, such as adenovirus or herpes simplex virus. A member of the genus Dependovirus in the family Parvoviridae, AAV has a T = 1 icosahedral capsid with a diameter of approximately 25 nm. The 4.7 kb single-stranded DNA genome contains two open reading frames: Rep and Cap. Rep encodes four alternatively spliced ​​proteins required for viral genome packaging and replication, while Cap encodes the capsid structural proteins VP1, VP2, and VP3 and the assembly activation protein (AAP).

The AAV genome is flanked by inverted terminal repeats (ITRs), which are essential for packaging, replication, and integration into the host genome. The ITRs are the only essential cis-acting elements in the AAV genome that enable different transgenes to integrate between the ITRs, which can then be packaged into the AAV capsid to generate recombinant AAV vectors (rAAV). Recombinant AAV can be generated by transfecting a plasmid containing the ITR-flanked transgene, the AAV capsid gene, and necessary accessory genes, followed by harvesting the transfected cells and purifying the virus. The use of rAAV for gene therapy has rapidly evolved over the past decade. During this time, rAAV technology has been significantly improved with the goal of increasing gene transfer efficiency, altering tropism, and/or reducing antigenicity.