Meet Adeno-Associated Virus, also known as AAV!
I have spent most of my scientific career working with AAV and have grown quite fond.
AAV (part of the parvoviridae family) is a small (25nm in diameter), non-enveloped, virus carrying single-stranded DNA. The capsid is made of 60 protein subunits (known as VP1, VP2, and VP3) arranged as an icosahedron. At the point where 5 subunits come together (5-fold axis) the virus forms a pore through which it is believed the genome enters. At the point where 3 subunits come together (3-fold axis) the virus extends spike protrusions, fundamental for cell binding and antibody recognition.
This virus, because of it’s small size, has a relatively simple genome (4.7kb) and is widely used as a gene therapy vector. Key portions of the viral genome that allow the virus to replicate are replaced with genetic material that acts therapeutically.
AAV cannot replicate entirely on its own – it needs either Adenovirus or HSV to make more of itself. Because of this, it is non-pathogenic in humans (does not cause illness).
There are currently two FDA approved AAV-based gene therapies – one for spinal muscular atrophy (SMA) and the other for a specific form of retinal dystrophy.
Posted on Instagram on February 20, 2021.