Validation of a new yeast-based reporter assay consisting of human estrogen receptors alpha/beta and coactivator SRC-1: application for detection of estrogenic activity in environmental samples.
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, ERalpha or ERbeta. These strains contain a reporter plasmid carrying an estrogen responsive element (ERE) upstream of the beta-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, 17beta-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 ERalpha and ERbeta are 5.31 x 10(-10) and 5.85 x 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 ERalpha and ERbeta assays. These yeast strains are useful and convenient for detecting and comparing the estrogenic ligand activities of environmental samples in response to ERalpha and ERbeta.
Chu
Wai-Ling
WL
Environmental Genetics Laboratory, Frontier Science Innovation Center and Graduate School of Science, Osaka Prefecture University, 1-2 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8570 Japan.
Shiizaki
Kazuhiro
K
Kawanishi
Masanobu
M
Kondo
Mami
M
Yagi
Takashi
T
D001681:Biological Assay; D004305:Dose-Response Relationship, Drug; D004784:Environmental Monitoring; D047628:Estrogen Receptor alpha / Q000378:metabolism*; D047629:Estrogen Receptor beta / Q000378:metabolism*; D004967:Estrogens / Q000032:analysis / Q000494:pharmacology*; D017930:Genes, Reporter; D051548:Histone Acetyltransferases / Q000378:metabolism*; D008024:Ligands; D056920:Nuclear Receptor Coactivator 1; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic / Q000187:drug effects; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000494:pharmacology*
D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D004967:Estrogens; D008024:Ligands; D014157:Transcription Factors; D014874:Water Pollutants, Chemical; D051548:Histone Acetyltransferases; C538859:NCOA1 protein, human; D056920:Nuclear Receptor Coactivator 1