Genetic manipulation of stem cells

Genetic engineering for dividing and proliferating cells, such as iPS and mesenchymal stem cells, must avoid insertional carcinogenesis. A strategy utilizing the integration machinery of a non-pathogenic adeno-associated virus (AAV) that achieves site-specific insertion of its genome into the AAVS1 locus on chromosome 19 minimizes the risk of insertional mutagenesis. The AAVS1 site is also reportedly one of the safe harbors for transgene insertion. Any DNA linked with the inverted terminal repeat (ITR) or the p5 promoter sequence with co-expression of AAV Rep protein is easily targeted to the AAVS1 site. Large DNA sequences exceeding 100 kb can be inserted at this site. The author introduces the principle of this method and the recent applications for iPS and other cells.