Fig. 4

Specificities of high-fidelity Cas9 variants in combination with HH-X₂₀ sgRNA. The HH-X₂₀ sgRNA expression plasmid was co-transfected with the plasmid encoding Cas9-WT or a Cas9 variant into HeLa cells. Indel frequencies at on- and off-target sites were measured by targeted deep sequencing. PAM sequences are shown in blue. Mismatched bases are shown in red. The specificity ratio indicates the fold difference between the ratio of on-target indel frequencies to off-target indel frequencies obtained using Cas9 variants and that obtained using Cas9-WT. Error bars, s.e.m. of three biological replicates. Indel frequencies significantly above those of the mock transfected sample are shown by asterisks (* P < 0.05, ** P < 0.01)