Adeno-Associated Virus-Mediated Delivery of CRISPR-Cas Systems for Genome Engineering in Mammalian Cells

The CRISPR-Cas9 system has emerged as a highly versatile platform for introducing targeted genome modifications into mammalian cells and model organisms. However, fully capitalizing on the therapeutic potential for this system requires its safe and efficient delivery into relevant cell types. Adeno-associated virus (AAV) vectors are a clinically promising class of engineered gene-delivery vehicles capable of safely infecting a broad range of dividing and nondividing cell types, while also serving as a highly effective donor template for homology-directed repair. Together, CRISPR-Cas9 and AAV technologies have the potential to accelerate both basic research and clinical applications of genome engineering. Here, we present a step-by-step protocol for AAV-mediated delivery of CRISPR-Cas systems into mammalian cells. Procedures are given for the preparation of high-titer virus capable of achieving a diverse range of genetic modifications, including gene knockout and integration.