FIG. 4.

Enhancement of the transcriptional activity of the ERα-ERβ heterodimer by cotransfection of H-Ras^V12. Cos-1 cells were transfected with 50 ng each of ERα and ERβ_GR or the serine-to-alanine mutants as indicated. The cells were treated with a control (0.1% ethanol) or 10 nM E₂ or also cotransfected with 100 ng of a dominant active form of Ras, H-Ras^V12, in the presence of E₂. Results are expressed as the response over basal levels in the absence of a ligand. A schematic representation of the effect of Ras on the transcriptional activity of each heterodimer complex is displayed on the right of the graph. Symbols are the same as in Fig. 3.