Adeno‐associated Viruses


Adeno‐associated viruses are small, nonenveloped, single‐stranded viruses of the genus Dependovirus, family Parvoviridae. They are so named because their propagation depends upon the coinfection by an unrelated virus for essential helper functions.

Keywords: parvoviridae; AAV; episomal persistence; recombinant viral vector; vector production; gene therapy; rep proteins; hairpin transfer replication; site‐specific integration

Figure 1.

Electron microscopy of (a) adeno‐associated virus 2 (AAV2) and (b) its helper virus, adenovirus 2. Note the few empty AAV particles that lack viral DNA genome and are imaged like a ring.

Figure 2.

The genome structure and gene products of adeno‐associated virus 2 (AAV2). ITR, inverted terminal repeat.

Figure 3.

The latent and productive life cycles of adeno‐associated virus (AAV). Ad, adenovirus.

Figure 4.

The terminal transfer model of linear adeno‐associated virus (AAV) DNA replication. The 3′ termini are indicated by an arrowhead, and newly synthesized DNA by dotted lines.

Figure 5.

Adeno‐associated virus (AAV) vector production by the helper virus‐free, triple‐plasmid transfection method, where no adenovirus is used nor can it be generated. Three of the five essential adenovirus (Ad) helper genes are provided by the helper plasmid (VA RNA, E2 and E4), while the other two genes (E1A and E1B) are provided by the host 293 cells. ITR, inverted terminal repeat.

Figure 6.

Efficient and long‐term gene transfer into mature muscle after direct injection of an adeno‐associated virus (AAV) vector that contains a β‐galactosidase gene from Escherichia coli. Transverse thin section of the vector‐injected mouse muscle showed blue‐coloured muscle cells across the entire area after X‐gal staining, which turned the β‐galactosidase‐positive cells blue. Magnification 40×.



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Further Reading

Berns KI and Giraud C (1996) Biology of adeno‐associated virus. Current Topics in Microbiology and Immunology 218: 1–23.

Muzyczka N (1992) Use of adeno‐associated virus as a general transduction vector for mammalian cells. Current Topics in Microbiology and Immunology 158: 97–129.

Samulski RJ, Sally M and Muzyczka N (1999) Adeno‐associated viral vectors. In: Friedmann T (ed.) Development of Human Gene Therapy, pp. 131–172. Cold Spring Harbor: Cold Spring Harbor Laboratory Press.

Tijssen P (ed.) (1990) Handbook of Parvoviruses. Boca Raton, FL: CRC Press.

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Xiao, Xiao(Jun 2001) Adeno‐associated Viruses. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1038/npg.els.0000408]