detecting-ligand-binding-domain-dimerization-activity-estrogen

Detecting the Ligand-binding Domain Dimerization Activity of Estrogen Receptor Alpha Using the Mammalian Two-Hybrid Assay

Estrogen receptor alpha (ER&#945;) is an estrogenic ligand-dependent transcription regulator. The sequence of ER&#945; protein is highly conserved among ...

National Institutes of Health (NIH)

Estrogen receptor α (ERα) is a major transducer of estrogen-mediated physiological signals. ERα is a member of the nuclear receptor superfamily, which encompasses ligand-dependent transcription factors. The C terminus of nuclear receptors, termed the F domain, is the least homologous region among the members of this family. The ERα F domain possesses 45 amino acids; however, its function remains unclear. We noticed that the homology of the F domains between mouse and human ERαs is remarkably lower (75.6% similarity) than that between the entire proteins (94.7% similarity). To assess the functionality of the ERα F domains, here we generated chimeric ERα expression constructs with mouse-human-exchanged F domains. Using cell-based  assays, we analyzed the transcriptional coactivator interaction and ligand-binding domain dimerization activities of these mouse-human F domain-swapped ERαs. We found that the transcriptional activity of the mouse WT ERα is more potent than that of the human WT ERα in the human hepatoma cell line HepG2. 4-Hydroxytamoxifen (4OHT)-mediated transcriptional activity of mouse-human F domain-swapped ERαs was the inverse of the WT ERα activities but not estradiol-mediated transcriptional activities. Further experiments with constructs containing deletion or point mutations of a predicted β-strand region within the F domain suggested that this region governs the species-specific 4OHT-mediated transcriptional activity of ERα. We conclude that the ERα F domain has a species-specific function in 4OHT-mediated receptor transactivation and that mouse-human F domain-swapped ERα mutants enable key insights into ERα F domain structure and function.

The F domain of estrogen receptor α is involved in species-specific, tamoxifen-mediated transactivation.

Studies using the estrogen receptor alpha (ERα) knock-out (αERKO) mice have demonstrated that ERα plays a crucial role in various estrogen-mediated metabolic regulations. ERα is a ligand dependent transcription regulator and its activity is regulated by estrogenic compounds. ERα consists of two transcriptional activation domains, AF-1 and AF-2. The activities of these domains are regulated through different mechanisms; however, the specific physiological role in metabolic regulation by these domains is still unclear.

Article	Year
The F domain of estrogen receptor α is involved in species-specific, tamoxifen-mediated transactivation. The Journal of biological chemistry\| PubMed ID: 29632071	2018
N-terminal transactivation function, AF-1, of estrogen receptor alpha controls obesity through enhancement of energy expenditure. Molecular metabolism\| PubMed ID: 30287090	2018

Yukitomo Arao

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