Fig. 2From: Ligase IV inhibitor SCR7 enhances gene editing directed by CRISPR–Cas9 and ssODN in human cancer cellsEffect of ssODN homology length on insertion efficiency at the AAVS1 locus. K562 cells were nucleofected with 4 μg of pCS2-Cas9-IRES-GFP-polyA-gRNA (AAVS1) co-expression vector and 0.3 nmol of ssODN donors with different lengths. Cells were harvested 2-day post nucleofection, and the GFP-positive cells were sorted. Genomic DNA was isolated and 100 ng DNA was used for PCR amplification with a P2P4 primer pair (a), or P2P4 and F1R1 primer pairs (b). The numbers on the top of the gel images represent the homology length in nucleotides of a ssODN donor. A 20-mer donor has two 10-base homology arms. Each ssODN contains an EcoRI site between the homology arms. The DNA sequence of each ssODN is shown in Supplementary Table 1. M: DNA Marker. NC: PCR control; CON1: normal cells; CON2: cells transfected with pCS2-Cas9-IRES-GFP-polyA-gRNA (AAVS1) co-expression vector only; CON3: cells transfected with ssODN donor (80 nucleotides) only; 20–80: cells transfected with pCS2-Cas9-IRES-GFP-polyA-gRNA (AAVS1) co-expression vector plus various lengths of ssODNA donors. Arrows indicate the predicted amplified fragmentsBack to article page