(A) Electrophoretic mobility shift assays were performed using HepG2 nuclear extracts with four different probes. Probe 1, lanes 1–4; probe 2 (1752A), lanes 5–8; probe 3, lanes 9–12; probe 4 (1752G), lanes 13–16. Each set of probes contains increasing concentrations (0.0 μg, 0.05 μg, 0.10 μg, and 0.15 μg) of non-specific competitor DNA [poly-(dI)-poly-(dC)], respectively.
(B) 40 μg of nuclear protein extracts obtained from HepG2 cells was allowed to bind onto 5 mg Dynabeads M-280 streptavidin-biotin-oligonucleotides in the presence of 2:1 (w/w) ratio of non-specific competitor DNA poly (dI–dC). 1-D isoelectric focusing was followed by 2-D vertical separation on SDS-PAGE (10%). The estimated molecular weight of the specific protein spots detected by silver staining (arrow) is indicated.