AAV5-CAG-GCaMP6m

AAV is a non-enveloped, single-stranded DNA virus belonging to the Parvoviridae family. The 4.7 kb genome contains two major open reading frames, Rep and Cap. Rep encodes four regulatory proteins (Rep78, Rep68, Rep52, and Rep40) that play important roles in viral DNA replication and encapsidation. Cap encodes three capsid proteins (VP1, VP2, and VP3) and the assembly activation protein (AAP) that promotes capsid formation. The genome is flanked by inverted terminal repeats (ITRs) containing Rep recognition sequences that are important for AAV DNA replication and packaging. As a dependoparvovirus, AAV requires the aid of another virus to propagate in tissue culture. Adenovirus and herpes simplex virus have traditionally been used as AAV helper viruses. AAV vectors are recombinant variants of the wild-type (wt) AAV virus in which the native coding and noncoding regions have been replaced by expression cassettes no larger than 4.7 kb. The vector genetic construct retains the flanking ITRs, the only cis-acting elements required for replication and packaging of AAV DNA. With these modifications, rAAV becomes a replication-defective entity that can only infect cells and deliver DNA into the nucleus. Vector production in culture requires the provision of the Rep and Cap genes in separate constructs. AAV genetic elements can be rearranged in multiple constructs and then delivered to host cells by plasmid transfection or viral infection. Helper virus activities are also required for efficient vector production. They are provided by co-infection with a helper virus stock or by transfection with a plasmid containing the "helper" genes.