Promotions & Discounts

  • Free 2 x 100ul aliquots of Virovek's AAV control vectors for all new customers! More

  • Special offer for all academic and non-profit organizations on Virovek's custom-made AAV vectors. More

  • Background

     

    What Is AAV

    Adeno-associated viruses (AAVs), from the parvovirus family, are small viruses (22 nm) that are replication-defective, non-enveloped, and with a genome of single stranded DNA.

    AAVs are non-pathogenic, as 80-90% of humans are sero-positive with AAV2. In contrast to adenoviruses, most people treated with AAV will not build an immune response to remove the virus and the cells that have been successfully transduced by it. Gene therapy vectors using AAV can infect both dividing and non-dividing cells and persist in an extrachromosomal state without integrating into the genome of the host cell.

     

    AAV Genome

    The AAV genome is built of single-stranded DNA, either positive- or negative-sensed. The total genome size that is able to be packaged is about 4.7 to 4.9 kilobase long. The genome comprises 145 nucleotide-long inverted terminal repeats (ITRs) at both ends of the DNA strand and two open reading frames (ORFs): rep and cap. The former is composed of four overlapping genes encoding Rep proteins required for the AAV life cycle, and the latter contains overlapping nucleotide sequences of capsids proteins, VP1, VP2, and VP3, which interact together to form a capsid of an icosahedral symmetry.

     

    Recombinant AAV

    The characteristics of AAVs have allowed the scientific community to establish methods for the production of recombinant AAV (rAAV) vectors. The only sequences required in cis next to the therapeutic gene (or gene of interest) are the ITRs. The structural (cap) and packaging (rep) genes can be delivered in trans. rAAVs are now widely used in both basic science research (single gene studies) and disease treatments (gene therapy).

     

    AAV Serotypes

    As many as 11 naturally-occurring AAV serotypes have been discovered (with many pseudotypes being generated by several different research groups). All of the known serotypes can infect cells from multiple diverse tissue types. Tissue specificity is determined by the capsid serotype, where serotype 2 (AAV2) has been the most extensively examined so far.

    The following is the table of AAV serotypes available through Virovek and their tissue specificity in vivo:

    AAV Serotype
    x → recommendable for use
    CNS/Eye Heart Liver Lung Skeletal Muscle
    AAV1 x x x x
    AAV2 x
    AAV5 x x
    AAV6 x x x x
    AAV8 x x x
    AAV9 x x x x x

    In general, serotype 2 transduces cells most effectively in vitro compared to the in vitro transudction efficacy of the other serotypes. All other serotypes transduce cells more effectively in vivo.