Estrogen Receptor-Mediated Transcription in Vitro
Abstract
Estrogen receptor (ER) is a ligand-activated transcription activator. To elucidate the mechanism of ER-mediated transcription in detail, we studied transcriptional activity of the ER in vitro. We demonstrated ER-mediated transcription in a cell-free transcription system is ligand- dependent. Antiestrogens ICI 164,384, ICI 182,780 and 4-hydroxytamoifen significantly inhibited transcriptional activity of the ER. Estradiol overcame the inhibitory effect of the anti estrogens and induced ER-mediated transcription. Under the condition used for transcription assays, ICI164,384 and ICI182,780 inhibited ER-ERE complex formation which might contribute to the inhibitory effect of these antiestrogens on ER-mediated transcription. hydroxytamoxifen changed the mobility of ER-ERE complex in the gel mobility shift assay, suggesting a conformational change of the complex. Steroid receptor coactivator 1 (SRC- 1) significantly augmented ER-mediated-transcription in vitro. The hormone binding domain (HBD) of the ER that binds to estrogen receptor associated proteins (ERAPs) in a ligand- dependent manner inhibited ER-mediated transcription in vitro. In contrast, the truncated ER HBD (ERdelta534) lacking of 535 to 595 amino acids of the ER which binds to estradiol but does not associate with ERAPs did not affect ER-mediated effect in this study, suggesting that ERAPs are required for the full transactivation activity of the ER.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1998
- Accession Number
- ADA384349
Entities
People
- Hong Liu
Organizations
- Northwestern University