The carboxy-terminal F domain of the human estrogen receptor: Role in the transcriptional activity of the receptor and the effectiveness of antiestrogens as estrogen antagonists

Monica M. Montano, Volkmar Müller, Angela Trobaugh, Benita S. Katzenellenbogen

Research output: Contribution to journalArticle

Abstract

Of the steroid hormone receptor family members, the estrogen receptor (ER) is notable in containing a sizable (42-amino acid) C-terminal region, denoted domain F. This F region differs from its adjacent hormone-binding domain, domain E, in that it is not well conserved among different vertebrate ER species, and its role in the biological activity of the ER is not well defined. We report an important role for the F domain of the ER in modulating the magnitude of gene transcription by estrogen and antiestrogen, and in determining the effectiveness of antiestrogens in suppressing estrogen-stimulated gene transcription. Using transient transfections, we have examined, in several cell types, the transcriptional activity of the full-length wild type human ER and ER lacking the carboxy-terminal F domain (Δ F ER, containing amino acids 1-554) or ER altered in the F domain by point mutations. In some cells, namely Chinese hamster ovary (CHO) cells and MDA-MB-231 human breast cancer cells expressing wild type ER or Δ F ER, estradiol (E2) stimulates equally transcription of several estrogen-responsive promoter-reporter gene constructs [estrogen ca-18119 element, (ERE)2-TATA-CAT, (ERE)2-pS2-CAT, (ERE)2-progesterone receptordistal-CAT]; however, the antiestrogens trans-hydroxytamoxifen and ICI 164,384, which stimulate transcription of some of these reporter constructs with the wild type ER, were unable to stimulate transcription with Δ F ER. In addition, these antiestrogens were more effective antagonists of E2-stimulated transcription by Δ F ER than by wild type ER. By contrast, in HeLa human cervical cancer cells and 3T3 mouse fibroblast cells, the Δ F ER exposed to E2 is much less effective than wild type ER in stimulating transcription, and antiestrogens were less potent in suppressing E2-stimulated transcription by the Δ F ER. These differences in response of the Δ F and wild type ER to estrogen or antiestrogen do not appear to be due to a change in receptor expression level, binding affinity for ligands, or binding to estrogen response element DNA. Our data support the supposition that the conformation of the receptor-ligand complex is different with estrogen vs. antiestrogen and with wild type vs. Δ F ER, such that its potential for interaction with protein cofactors or transcription factors is different and is markedly influenced by cell context. Thus, the F domain of the ER has a specific modulatory function that affects the agonist/antagonist effectiveness of antiestrogens and the transcriptional activity of the liganded ER in cells.

Original languageEnglish (US)
Pages (from-to)814-825
Number of pages12
JournalMolecular Endocrinology
Volume9
Issue number7
DOIs
StatePublished - Jul 1 1995

ASJC Scopus subject areas

  • Molecular Biology
  • Endocrinology

Fingerprint Dive into the research topics of 'The carboxy-terminal F domain of the human estrogen receptor: Role in the transcriptional activity of the receptor and the effectiveness of antiestrogens as estrogen antagonists'. Together they form a unique fingerprint.

  • Cite this