AAV gP120-CAG-GFP

Adeno-associated virus (AAV) is a single-stranded DNA virus of the Parvoviridae family that has become an ideal candidate for gene therapy due to its lack of pathogenicity and relatively stable expression of therapeutic genes. The transformative potential of AAV is further supported by its multiple serotypes [AAV1-rh10]. Each AAV serotype has a unique capsid sequence that determines their interaction with host cells. The AAV capsid is icosahedral and consists of 60 subunits. The three viral capsid proteins VP1, VP2, and VP3 are present in a 1:1:10 ratio, while the assembly activation protein (AAP) facilitates the assembly of the viral capsid. These viral proteins share a common C-terminal region but are generated by alternative splicing of the right open reading frame (ORF) of the AAV genome. The differences in structural protein sequence homology between different AAV serotypes confer unique binding affinities to various host cell surface receptors. Several other regions of the viral capsid are known to have evolved to manipulate host cell processes for successful infection. The N-terminus of VP1 contains a conserved phospholipase A2 (PLA2) domain that plays an important role in the endosomal escape of the virus. In addition, it has been reported that there are multiple nuclear localization signals (NLS) at the N-termini of capsid VP1 and VP2 that can be recognized by the cellular trafficking machinery to promote nuclear transport. In addition, sequence differences within the VP3 region are known to be one of the reasons for the differences in tissue tropism of AAV vectors.