Figure 4.

POLQ mutation signature accumulates in the absence of NHEJ in proximal EJ. (A) HPRT locus was targeted by CRISPR/Cas9. The cells expressing OFP, a co-expression marker, were isolated and the products of proximal EJ were characterized by target site amplification and high-throughput sequencing (NGS). The percentage of all proximal end-joining products with no mutation (B) and a POLQ mutation signature (deletion overlapping with 3–6 bp MH at the proximal end-joining site) (C). Unpaired t-tests were performed for statistic comparison. Parental DR-U2OS and POLQ^−/− clones (F10 and G6) are infected with shControl (shC), shDNA-PKcs or sh53BP1.