Sequence specific binding of Ets-1 to the mouse cytokeratin EndoA gene enhancer.

Expression of the mouse cytokeratin EndoA gene is regulated by an enhancer that is located 1 kilobases (kb) 3' downstream from the gene. The EndoA enhancer consists of six direct repeats with homology to the PEA3 motif in the polyoma virus enhancer core. The PEA3 motif binds to the proto-oncogene Ets product. In this report we show that GST-c-Ets-1 fusion protein binds specifically to the EndoA enhancer unit sequence by gel shift analysis. Footprinting showed that the Ets-1 binding site consisted of 20 bases in each repeat. Ets-1 also moderately activated the EndoA enhancer. These results demonstrate that Ets-1 binds in a sequence specific fashion to the mouse EndoA enhancer and suggest that c-Ets-1 or other related Ets family genes function in regulating EndoA gene expression.