Figure 2.

Schematic illustration of a gene knockout using CRISPR/Cas9 gene editing. (A) Two gRNAs were designed on the coding start region and 3′ untranslated region (UTR), respectively, of gene of interest (GOI) to cut out about 9 kb. The light blue rectangles and green rectangles show coding sequences and UTRs, respectively. The screening primers are located outside of the gRNAs. (B) PCR is performed on DNA isolated from individual clones of cells subject to gene editing. The extension time is purposefully brief, so that the 9-kb WT allele cannot be amplified. Different sizes of deleted alleles are detected, because each clone has different deletion lengths near the DSB.