High-throughput capture of ectopic chromosomal sequence

DNA double-strand breaks (DSBs) are a prominent source of genetic instability/variability frequently associating genome rearrangements with the capture of ectopic chromosomal sequences (ECSs) at junctions. Homologous recombination (HR) is considered in textbooks as an error-free DSB repair mechanism that protects against genome instability. Contradicting this dogma, we show that silencing the central HR players RAD51 or BRCA2 suppresses the sequence homology-independent capture of ECS at the junctions of distant DSBs, especially in 53BP1-depleted cells. We confirmed the requirement of RAD51 for ECS capture at a genome-wide level through high-throughput genome translocation sequencing. Overall design: We performed HTGTS on human fibroblasts CG92 cell line contained the CD4-3200 bp (pSHD-CD4) end-joining reporter and CMV6 primer was used as bait to capture ectopic chromosomal sequences. The captured of ectopic chromosomal sequences (ECSs) at junctions were analyzed and compared among no treatment, si53BP1, siRAD51, si53BP1&siRAD51 cells.