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Role of the two activating domains of the oestrogen receptor in the cell‐type and promoter‐context dependent agonistic activity of the anti‐oestrogen 4‐hydroxytamoxifen.
Author(s) -
Berry M.,
Metzger D.,
Chambon P.
Publication year - 1990
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1990.tb07469.x
Subject(s) - biology , agonist , context (archaeology) , receptor , transfection , reporter gene , antagonist , agonistic behaviour , partial agonist , hela , endocrinology , microbiology and biotechnology , medicine , gene , cell culture , gene expression , genetics , paleontology , psychology , psychiatry , aggression
Various oestrogen responsive reporter genes and vectors expressing truncated or chimeric human oestrogen receptors (hER) containing either of the two independent hER transcriptional activation functions (TAF‐1 and TAF‐2) have been transfected into HeLa cells, chicken embryo fibroblast (CEF) or yeast cells to investigate the agonistic activity of the anti‐oestrogen 4‐hydroxytamoxifen (OHT). We demonstrate that the agonistic effect of OHT on the whole hER is due to the cell‐type and promoter‐context dependent activity of TAF‐1. In similar experiments, we show that the anti‐oestrogen, ICI 164,384, does not exhibit any oestrogenic activity and, therefore, acts always as a pure antagonist, even though it does not inhibit the activity of the isolated TAF‐1. We also confirm that the wild type human oestrogen receptor has no ligand independent transcriptional activity. The implications of our results for the variable antagonist/agonist activity of anti‐oestrogens in vivo are discussed.