AAV2-hSyn-mCherry

The wild-type viral genome of the canonical adeno-associated virus (AAV) serotype 2 is a ssDNA genome of approximately 4,700 nt containing multiple genes with overlapping reading frames. The ends of the genome are surrounded by 145 nucleotide (nt) inverted terminal repeat (ITR) sequences that are predicted to fold on themselves to form a hairpin structure. The Cap gene produces the capsid VP proteins and also contains the reading frame for AAP which helps in assembly of the capsid.

The AAV2 Rep gene produces four proteins named after their approximate weights: Rep78, Rep68, Rep50, and Rep42. The smaller Rep 50 and 42 can act as motor proteins to package the nascent genome into preformed capsids. The larger Rep 78 and 68 have endonuclease and ATP-dependent helicase functions that are required for genome replication. These large Reps can initiate genome replication by binding to the Rep binding element (RBE) in the ITR A region. This initial binding helps unwind the DNA strands and form the nicked stem, which is cleaved by Rep at the dinucleotide TT terminal resolution site (trs). In addition, the large Rep protein also contacts the RBE' region at the end of the C-loop. The ITRs play a fundamental role in the AAV life cycle by containing the origin of replication, packaging signals, and the ability to confer persistence to the AAV genome after infection.