Syn-FLEX-GCaMP6m AAV (Serotype 8)

AAVs are small viruses (25 nanometers) of the genus Dependovirus in the family Parvoviridae, which indicates that they are dependent on a helper virus for efficient infection. These viruses have a non-enveloped capsid and store their genetic material in the form of single-stranded DNA. AAVs rely on helper viruses (such as adenovirus and herpes simplex virus) for replication and can infect both dividing and non-dividing cells. These properties make them potential agents for gene therapy of post-mitotic cells such as neurons. The 4.7 kb genome of AAV consists of ORFs containing the rep gene encoding proteins involved in viral replication, the cap gene encoding structural proteins required for capsid formation, and the aap gene required for the final assembly of capsid proteins. These ORFs are interlaced with two ITRs, which are cis-acting elements required for viral replication and packaging. Depending on the presence or absence of a helper virus, these viruses undergo either a lytic or lysogenic cycle, respectively. In the lytic cycle, the virus replicates its genome with the help of the host DNA polymerase and then produces virions. For the lysogenic cycle, the virus integrates into the host genome in a site-specific manner and requires helper virus rescue to return to the lytic state. For gene therapy, recombinant AAV vectors are constructed by replacing the ORF with the gene of choice and retaining the ITR. The helper functions required to maintain the lytic cycle are provided by co-transfection of plasmids containing the genes that confer these requirements.