GFP Adeno-Associated Virus ( DMD6 )

Adeno-associated viruses (AAVs) are 20 to 25 nm single-stranded DNA (ssDNA) viruses belonging to the Parvoviridae family. Their genome consists of two genes, rep and cap, flanked by two 145 bp inverted terminal repeats (ITRs) and packaged into a T = 1 icosahedral capsid. The capsid consists of 60 protein subunits arranged in a precise stoichiometric manner. The cap gene encodes the VP1, 2, and 3 C-terminal overlapping proteins that form the viral capsid, while the rep gene encodes four multifunctional proteins involved in essential tasks of viral replication, such as DNA binding, site-specific endonuclease activity, and helicase activity. Due to its favorable toxicity and immunogenicity profiles, its ability to mediate stable and long-term expression of therapeutic transgenes, and its ability to efficiently transduce both dividing and non-dividing cells, AAV has emerged as an effective gene transfer vector system for gene therapy of inherited and acquired diseases. However, AAV is still hampered by low efficiency of delivery to disease-relevant organs and cell types. Native AAV capsids can be modified to generate vectors with significantly improved in vivo tropism. An effective engineering strategy is to generate libraries of different capsid variants through peptide insertion and subject these libraries to multiple rounds of in vivo selection to identify capsids with desired properties, such as central nervous system (CNS)-wide transduction, brain endothelial targeting, retrograde transduction in the CNS, transduction of human hepatocytes in xenograft systems, photoreceptor transduction, and muscle transduction.