Syn-FLEX-NES-jRGECO1a AAV (Serotype 8)

Adeno-associated virus (AAV) is a ssDNA, non-enveloped, small (~26 nm in diameter), T = 1 virus of the genus Dependoparvovirus in the family Parvoviridae. Dependoparvovirus has been isolated from a variety of mammals, including humans, non-human primates, cattle, goats, pigs, sea lions, foxes, rodents, and bats. In addition, members of this genus have also been found in birds and reptiles. The structures of many AAV serotypes, variants, and isolated capsids have been determined by X-ray crystallography and/or cryo-electron microscopy (cryo-EM). All AAV capsid structures exhibit common features such as a channel at the 5-fold axis, protrusions around the 3-fold axis, and depressions around the 2-fold axis and 5-fold channel. The capsid is composed of three overlapping structural viral proteins (VPs), the minor proteins VP1 (~80 kDa) and VP2 (~65 kDa), and the major protein VP3 (~60 kDa). A total of 60 VPs are contained in the capsid in a ratio of approximately 1:1:10. The amino acid sequence of VP3 is identical to the two minor capsid proteins, while VP2 has an N-terminal region shared with VP1 (the VP1/2 common region). The VP1/2 common region contains nuclear localization motifs that have been shown to play an important role in localizing incoming capsids to the nucleus following infection of cells with AAV. In addition, VP1 contains a unique N-terminal sequence, called the VP1 unique region (VP1u), which contains a phospholipase A2 domain that is required for endosome escape during cellular trafficking via the intralysosomal pathway. The N-termini of VP1 and VP2 are thought to be located inside the capsid and are externalized after structural rearrangements following endosomal acidification during cellular trafficking.