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Validation of a new yeast‐based reporter assay consisting of human estrogen receptors α/β and coactivator SRC‐1: Application for detection of estrogenic activity in environmental samples
Author(s) -
Chu WaiLing,
Shiizaki Kazuhiro,
Kawanishi Masanobu,
Kondo Mami,
Yagi Takashi
Publication year - 2009
Publication title -
environmental toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.813
H-Index - 77
eISSN - 1522-7278
pISSN - 1520-4081
DOI - 10.1002/tox.20473
Subject(s) - phytoestrogens , coactivator , reporter gene , estrogen receptor , nuclear receptor coactivator 1 , endocrine disruptor , yeast , estrogen , diethylstilbestrol , biology , saccharomyces cerevisiae , nuclear receptor , receptor , estrogen receptor alpha , chemistry , hormone , endocrine system , biochemistry , endocrinology , gene , transcription factor , gene expression , genetics , cancer , breast cancer
Endocrine disruptors are exogenous substances that act like hormones in the endocrine system and disrupt the physiologic function of endogenous hormones. In the present study, we established reporter yeast strains ( Saccharomyces cerevisiae ) expressing human estrogen receptors, ERα or ERβ. These strains contain a reporter plasmid carrying an estrogen responsive element (ERE) upstream of the β‐galactosidase gene, and a plasmid expressing a steroid receptor coactivator, SRC‐1e. Using these reporter strains, we demonstrated dose‐dependent estrogenic activities of different categories of ligands, a natural hormone, 17β‐estradiol (E2); a synthetic drug, diethylstilbestrol (DES); phytoestrogens, genistein, daizein and emodin; and an environmental endocrine disrupter, bisphenol A. EC 50 values of E2 for ERα and ERβ are 5.31 × 10 −10 and 5.85 × 10 −10 M, respectively. We also demonstrated that these yeasts were applicable for measuring estrogenic activities of environmental water samples. Most downstream sites of a river showed similar activity in both ERα and ERβ assays. These yeast strains are useful and convenient for detecting and comparing the estrogenic ligand activities of environmental samples in response to ERα and ERβ. © 2009 Wiley Periodicals, Inc. Environ Toxicol, 2009.