Authors used 2×106 PGP1 iPS cells which were resuspended in P3 reagent with 1µg Cas9 plasmid, 1µg gRNA and/or 1µg DNA donor plasmid, and nucleofected. Cells were subsequently plated on an mTeSR1-coated plate in mTeSR1 medium supplemented with ROCK inhibitor for the first 24h. For K562s, 2×106 cells were resuspended in SF reagent with 1µg Cas9 plasmid, 1µg gRNA and/or 1µg DNA donor plasmid, and nucleofected. The DNA donors used for endogenous AAVS1 targeting were either a dsDNA donor or a 90mer oligonucleotide. Cells were harvested 3 days after nucleofection and the genomic DNA of ~1 X 106 cells was extracted and analyzed to estimate NHEJ efficiencies.
Bacteria and archaea have evolved adaptive immune defenses, termed clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) systems, that use short RNA to direct degradation of foreign nucleic acids. Here, we engineer the type II bacterial CRISPR system to function with custom guide RNA (gRNA) in human cells. For the endogenous AAVS1 locus, we obtained targeting rates of 10 to 25% in 293T cells, 13 to 8% in K562 cells, and 2 to 4% in induced pluripotent stem cells. We show that this process relies on CRISPR components; is sequence-specific; and, upon simultaneous introduction of multiple gRNAs, can effect multiplex editing of target loci. We also compute a genome-wide resource of ~190 K unique gRNAs targeting ~40.5% of human exons. Our results establish an RNA-guided editing tool for facile, robust, and multiplexable human genome engineering.