CELE_Y48G1BL.2

Protein ATM-1

CELE_R07E5.8, R07E5.8

cku-80 encodes an ortholog of human XRCC5 (Ku80; OMIM:194364, antigen of systemic lupus erythematosus); CKU-80 is required for resistance to ionizing radiation (IR) in somatic tissues (such as motor neurons, vulva, uterus, or somatic gonad) and in endoreduplicating intestinal cells, but not in the germline (e.g., in dog-1-induced lesions); CKU-80 is required for growth on high NaCl, probably because excess NaCl induces extensive chromosome breakage; CKU-80 is also required for survival of dauer larvae subjected to IR, and resistance of developing embryos to methyl methane sulfonate; CKU-80 binds CKU-70 in yeast two-hybrid assays, and requires HIM-10 for fully effective DNA repair in somatic cells; by orthology, CKU-80 is expected to function (as a heterodimer with CKU-70) in nonhomologous end-joining of double-stranded breaks in DNA; although CKU-80 is not strongly required in the germline, its absence enhances the hypersensitivity of rad-51(RNAi) germlines to ionizing radiation; mutant cku-80 late-stage embryos or dauer larvae are hypersensitive to radiation-induced DNA damage in somatic cells; after irradiation, cku-80 mutants tend to display various postembryonic phenotypes (such as slow growth, uncoordinated locomotion, impaired egg-laying, or vulval defects) that are enhanced by him-10 mutations, and that are thought to reflect missegregation of fragmented chromosomes; in two-hybrid assays, CKU-80 binds (in addition to CKU-70) DAF-21, CAH-3, and F59A2.5.