Fig. 4.

Distinct domains of ERα are required for recruitment and transcription activation through AP-1. (A) Multiple domains of ERα are necessary for efficient ERE- and AP-1-dependent transcription. (Left) Schematic representation of the ERα mutants used in these studies. Templates containing two EREs or two AP-1 sites upstream of the adenovirus E4 promoter were assembled into chromatin and transcribed in the presence of wild-type or mutant ERα± E₂ (and Ral, for the AP-1 template). The results of transcription assays are summarized (Right), with “+” indicating 100% activity and “-” indicating <5% of transcriptional activity of wild-type ERα. (B) The DBD of ERα is required for recruitment by native DNA-bound Fos/Jun heterodimers to an immobilized DNA template containing AP1 sites. Bound ERα was detected by Western blotting using an antibody to ERα (or to FLAG, for the ERαΔAB experiment).