Fig. 4. HSF1–HSE complexes in the hepatocytes of Trematomus bernacchii, visualized via electrophoretic mobility shift assay (EMSA). A competition assay was run to determine HSE probe specificity. 25 µg of homogenized hepatocyte preparation was incubated with 15 pmol of ³²P-labeled HSE probe for 20 min at 0°C and then separated on a 5% non-denaturing polyacrylamide gel. Gels were dried and exposed to a phosphoscreen. HSF1–HSE complexes were visualized on a phosphoimager. Lane 1: hepatocyte sample and radiolabeled HSE probe only. Lane 2: identical to lane 1 except for the addition of a 200 mol l^–1 excess of an unlabeled non-competitor DNA probe (AP2 from Promega). Lane 3: identical to lane 1 except for addition of a 200 mol l^–1 excess of unlabeled HSE probe.