Figure 6.

GAG-hed blocks AP1 binding. AP1 DNA binding was performed using electrophoretic mobility shift assays (EMSA) with oligonucleotides containing the HPV18 AP1 binding sequence and the SV40 SP1 bona fide site. Oligomers were end labelled with [α-³²P] dATP or [α-³²P] dCTP. Nuclear extracts obtained from HeLa cells were exposed to GAG-hed at indicated concentrations for 10 min before labelled probe addition (Panels B and D). On panel A and C, complex specificity is denoted by competition assays with a 100 fold excess of indicated oligonucleotide competitor. In panel E and F, AP1 and SP1 binding respectively, was tested with the same nuclear protein extract obtained from HeLa cells treated in vivo with 5 mg/ml of GAG-hed and harvested 48 h post-treatment. Control indicates untreated cells.