ERCC6L2 suppresses chromosome translocation

ERCC6L2 is a recently characterized component in DNA damage repair. To investigate its function in chromosome translocation, we conducted a study using K562 and HEK293T cell lines. We introduced twinned DNA double-strand breaks (DSBs) or genome-wide DSBs into these cell lines via nucleofection and transfection, respectively. Subsequently, we employed high-throughput genome translocation sequencing (HTGTS) to capture the translocation events (i.e., ligation between "prey(s)" and "bait") and the rejoining events (i.e., direct repair within the "bait" locus) under different conditions, including with or without ERCC6L2 deletion. We quantified the number of translocation events by normalizing them to the number of rejoining events, denoted as TL. Interestingly, ERCC6L2 deletion led to an increase in TL, indicating a higher frequency of translocations. We induced DNA double-strand breaks (DSBs) using CRISPR-Cas9 technology in various cell lines, including K562-derived cell lines (K562 and K562-ERCC6L2-/-) and the HEK293T-derived cell lines (HEK293T-iCas9 and HEK293T-iCas9-ERCC6L2-/-). To capture translocation events, we utilized one of the DSB sites, RAG1L as a bait, which allowed us to detect its ligation with the remaining DSB site(s) using high-throughput genome translocation sequencing (HTGTS).