AAV Capsid Libraries

The various serotypes and variants of AAV that have been described can transduce a wide array of cells. Yet, the limited diversity of natural AAV serotypes restricts the application of AAV gene therapy vectors to certain target tissues and associated diseases. To enable cell- or tissue-directed gene expression, many artificially generated AAV variants have been established, often isolated from large pools of mutated capsids.

Methods to make AAV libraries

Over the past few years, several methods have been developed to select AAV vectors. Among the most popular approaches to select AAV variants with improved properties is directed evolution using libraries of AAV variants with diverse AAV capsids. High complexity AAV libraries can be created by a number of methods, e.g. by inserting degenerate peptides into hypervariable surface loops, via the use of error-prone PCR to introduce point mutations into the AAV capsid or through so-called capsid shuffling.

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Random mutagenesis
Error PCR.png
DNA shuffling
DNA shuffling.png
Random Peptide display
RP.png
Semi-random loop replacement
Semi-loop2.png