The GR usually binds DNA as a homodimer; however, it has been demonstrated that monomers can bind to ‘half-sites’ and modulate transactivation when they are either close to the TATA element or can cooperate synergistically with other transcription factors (Strahle et al. 1988). The GRE #1 site we identified is 47 bp 5′ to the TATA element, and perhaps another cryptic GRE is present within this region that we have not yet identified. Another site for GR binding might explain the repression observed with dexamethasone treatment as well as the reduction of the protein:DNA complex observed in the EMSA if GR binding would modulate the occupancy of other regulators of SEPP1 expression.
