Characterization of activated NF-κB in HepG2 cells. (a) The activation of NF-κB by TNF-α in HepG2 cells was studied using EMSA. The nuclear extract was prepared after 1-hour treatment with TNF-α. (b) Characterization of NF-κB complex by supershift analysis. The antibodies specific to NF-κB subunits were used in EMSA. mut, mutated; oligo, oligonucleotide.