Fig. 4.

The efficiency of gene deletion is increased dramatically using optimized sgRNAs. a The CCR5 gene deletion. b sgRNA pairs targeting CCR5 with the original or optimized structures were co-transfected into TZM-bl cells with a Cas9-expressing plasmid. The gene deletion efficiency was determined by amplifying the CCR5 gene fragment. Note that the truncated fragments of CCR5, with a smaller size than wild-type CCR5, are a consequence of gene deletion using paired sgRNAs. The numbers below each lane indicate the percentage deletion