FIG. 2.

Altered response element specificity of ER DNA-binding mutants. (A) Amino acid sequence of the first zinc finger module of the mouse ERβ DBD. Arrows indicate the positions of the three amino acids that were changed to create the mutant ERβ_GR, which has the ability to recognize the half-site sequence AGAACA but can no longer bind to the half-site core motif AGGTCA. (B) Sequence of hormone response elements used in this study. White and black arrows illustrate consensus ERE and GRE half-sites, respectively. (C) Cos-1 cells were cotransfected with the vERE₁TKLuc reporter construct and either the wild-type ER (ERα and ERβ) or the GRE-specific ER (ERβ_GR and HE82) expression plasmids. Cells were treated with a control (0.1% ethanol) or 10 nM E₂ in the absence or presence of 100 nM of the pure antiestrogen EM-652. (D) Transfection conditions are identical to those for panel C except that the cells were cotransfected with the GRE₃TKLuc reporter construct. (E) Cos-1 cells were cotransfected with E/GRE₂TKLuc and wild-type or GRE-specific ERs separately or in combination as indicated.