An essential receptor for adeno-associated virus infection

An adeno-associated virus (AAV) receptor protein essential for AAV2 entry into cells is identified; AAV receptor binds directly to the virus, and its ablation renders a diverse range of mammalian cell types and mice resistant to infection by AAV of multiple serotypes. A receptor for adeno-associated virus infection The recent revival of interest in gene therapy has been fueled by the availability of safer and more effective viral gene delivery methods, most notably adeno-associated virus (AAV) vectors. Jan Carette and colleagues now identify a protein that is essential for AAV entry into cells, subsequent to cell attachment. This protein, which they call AAVR, rapidly traffics from the plasma membrane to the trans -Golgi network. The authors show that the virus directly binds to AAVR and that genetic ablation of AAVR renders a diverse range of mammalian cell types and mice resistant to AAV infection. Adeno-associated virus (AAV) vectors are currently the leading candidates for virus-based gene therapies because of their broad tissue tropism, non-pathogenic nature and low immunogenicity 1 . They have been successfully used in clinical trials to treat hereditary diseases such as haemophilia B (ref. 2 ), and have been approved for treatment of lipoprotein lipase deficiency in Europe 3 . Considerable efforts have been made to engineer AAV variants with novel and biomedically valuable cell tropisms to allow efficacious systemic administration 1 , 4 , yet basic aspects of AAV cellular entry are still poorly understood. In particular, the protein receptor(s) required for AAV entry after cell attachment remains unknown. Here we use an unbiased genetic screen to identify proteins essential for AAV serotype 2 (AAV2) infection in a haploid human cell line. The most significantly enriched gene of the screen encodes a previously uncharacterized type I transmembrane protein, KIAA0319L (denoted hereafter as AAV receptor (AAVR)). We characterize AAVR as a protein capable of rapid endocytosis from the plasma membrane and trafficking to the trans -Golgi network. We show that AAVR directly binds to AAV2 particles, and that anti-AAVR antibodies efficiently block AAV2 infection. Moreover, genetic ablation of AAVR renders a wide range of mammalian cell types highly resistant to AAV2 infection. Notably, AAVR serves as a critical host factor for all tested AAV serotypes. The importance of AAVR for in vivo gene delivery is further highlighted by the robust resistance of Aavr −/− (