RAD51 promotes the knock-in efficiency of CRISPR/Cas9. (A) Knock-in process of DsRed cassette. sgRNA targeting the terminal region of exon 6 of the GAPDH gene cuts that locus, allowing genomic integration of the DsRed cassette through HDR. (B) Cartoon for DsRed-expressing cells by CRISPR/Cas9-mediated knock-in system. (C) Representative images showing DsRed expression in CRISPR/Cas9 system (GFP) through the knock-in process. Due to the exogenous promoter of the DsRed cassette, the expression of DsRed was shown in normal condition. (D) Histogram describes the cell number according to the amount of DsRed intensity in each condition. (E) Quantitative analysis of FL2-H implying DsRed fluorescence measured in (D). Error bars indicate the mean ± SD (n = 3). Statistical significance, *P < 0.05, **P < 0.01, ***P < 0.001. (F) Proposed working mechanism of RAD51-mediated CRISPR/Cas9 system.
