(A) EMSA cold competition assay. 20-fold of unlabeled c-jun element DNA including wild type (WT, 5’- CCGTGAGCCTCCGCGGG -3’, annealed to its complement) and mutant (MUT, 5’-TCTGGGCCCGCGACGTGCAACGGGATGAGGT-3’ annealed with its complement) is added to EMSA reaction with radiolabeled WT duplex oigonucleotide for cold competition assay. NP, no protein; NC, no cold DNA; C, specific complex; U, non-specific complex. (B) EMSA antibody supershift assay. 40 ng of Ku80 antibody (Ku80) or control IgG (IgG) is incubated with HEK293 nuclear extract before EMSA reaction with radiolabeled WT duplex oigonucleotide for antibody supershift assay. NP, no protein; S, supershift band; C, specific complex; U, non-specific complex.