(Upper) EMSA with the 27h probe and increasing concentrations of HeLa nuclear extracts. The radiolabelled probe (10 nM) was incubated in 50 mM HEPES buffer pH 7.2, containing 0.1 M KCl, 1 mM MgCl2 and 5% sucrose, in the presence of ds26 and dT26 (0.5 µg/µl each) and various concentrations of HNE for 15 min on ice and run at 4°C on an 8% polyacrylamide gel (see Materials and Methods). Lane 1, no protein; lanes 2–10, increasing concentrations of HNE (1.7, 4.25, 8.5, 17, 42.5, 85, 170, 425 and 850 ng/µl). (Lower) Quantification of the radioactivity in the different bands divided by the total radioactivity in the lane. Closed circle, free probe; closed diamond, band D; open circle, band K; open diamond, band C.