Comparative EMSA analyses of nuclear extracts from H4IIEC3 cells and adult rat liver, brain, lung and dedifferentiated H5 cells, for binding to DNA sequences from –81 to –61 of the rat carboxylase gene 5′-flanking region. Panel A shows cold competitor WT or mutant oligonucleotides (E, F, G, H, I, J) were added in 100-fold molar excess, as indicated above each lane, in EMSAs with adult rat liver nuclear extract. (–) indicates no added competitor. H4IIEC3 nuclear extract without competitor is shown in the left lane, as indicated. The arrow indicates the position of the upper complex referred to in “Results” and “Discussion.” Panel B shows radiolabeled wild-type double-stranded oligonucleotide containing the 12-bp core sequence was used in EMSA analysis with 5 μg total nuclear protein in each sample. The source of nuclear extract is indicated above each lane. The arrow indicates the position of the specific upper complex referred to in “Results” and “Discussion.” Free indicates no added nuclear protein.