Figure 3

DNAse I digestion of the CNS87 and EMSA assays. A) DNAse I footprinting analysis of the CNS87 in the absence (-) or presence (+) of PC Cl3 protein extract. A sequence ladder of the CNS87 fragment (G+A) was used as size marker. The regions protected are indicated by lines and named FT-1 to FT-6; B) EMSA assays were performed to determine the cell-type specificity of the proteins binding to the CNS87. Protein extract from PC Cl3 (thyroid) and HeLa (non-thyroid) cells were used with a set of probes derived from the FT sequences; C) Bacterially-purified TTF-1 (bTTF1) was used in EMSA assays in comparison with PC Cl3 total protein extract. Oligo C was used as control. The retarded pattern is maintained in EMSA assays with FT-1 and FT-6 probes demonstrating that TTF-1 is binding to both probes.