C17orf53 defines a novel pathway involved in inter-strand crosslink repair

ATR kinase is a master regulator of genome maintenance and participates in DNA replication and various DNA repair pathways. In a genome-wide screening for ATR-dependent fitness genes, we identified a previously uncharacterized gene, C17orf53, whose loss led to hypersensitivity to ATR inhibition. C17orf53 is conserved in vertebrate and is required for efficient cell proliferation. Loss of C17orf53 slowed down DNA replication and led to pronounced ICL repair defect. Further genetic analyses revealed that C17orf53 functions downstream in ICL repair pathway, probably by affecting the loading of repair factors such as RAD54. In addition, we showed that C17orf53 is a ssDNA- and RPA-binding protein, both of which are important for its functions in the cell. Taken together, C17orf53 is a novel component involved in ICL repair pathway.