Fig. 6.

HDR and NHEJ efficiency evaluation by traffic light reporter (TLR) assay. a Diagram depicting the work principle of TLR system. b FCM detection of HDR and NHEJ events after either LION- or plasmid-TLR gRNA transfection in HEK293 TLR cells. A TLR HDR donor vector was co-transfected in each group. Two versions of Cas9 were evaluated (the original wild-type SpCas9 and the recombinant SpCas9–RecA) in both LION and plasmid groups. SpCas9 without gRNA was used as negative control group. c FCM quantification of GFP-positive cells (n = 3) and d RFP-positive cells as percentage in LION and plasmid groups (n = 3). e GFP- and RFP-positive cells ratio in the two groups (n = 3). Asterisk (*) indicates a p value less than 0.05 and (**) less than 0.01