title: Ability of structurally diverse natural products and synthetic chemicals to induce gene expression mediated by estrogen receptors from various species.
abstract: The ability of 14 structurally diverse estrogenic compounds to induce reporter gene expression mediated by estrogen receptors (ERs) from different species was examined. MCF-7 cells were transiently transfected with a Gal4-regulated luciferase reporter gene (17m5-G-Luc) and Gal4-ER chimeric receptors containing the D, E and F domains of the human alpha (Gal4-hERalphadef), mouse alpha (Gal4-mERalphadef), mouse beta (Gal4-mERbetadef), chicken (Gal4-cERalphadef), green anole (Gal4-aERalphadef), Xenopus (Gal4-xERdef) or rainbow trout alpha ERs (Gal4-rtERalphadef). The efficacy of 17beta-estradiol (E2) in inducing reporter gene expression was similar among the different constructs overall, with EC(50) values ranging from 0.05 to 0.7nM. However, Gal4-rtERalphadef had an EC(50) value at 37 degrees C of 28nM, though at 20 degrees C an EC(50) value of 1nM was observed. Despite a similar response to E2 treatment among the ERs, many differences were observed in the magnitude of the response to other structurally diverse chemicals. For example, coumestrol induced Gal4-mERbetadef- and Gal4-aERdef-mediated reporter gene expression 164- and 8-fold greater, respectively, than mediated with the other Gal4-ERs. As well, in contrast to results with other Gal4-ERs, alpha-zearalenol consistently induced Gal4-rtERalphadef-mediated reporter gene activity at lower concentrations than did E2. Overall, the results demonstrate that selected estrogenic compounds exhibit a differential ability to induce reporter gene activity mediated by ERs from different vertebrate species. These data also highlight the importance of incubation temperature when examining rtERalpha-mediated activity.
authors.affiliation: Department of Biochemistry and Molecular Biology, Institute for Environmental Toxicology and National Food Safety and Toxicology Center, Michigan State University, East Lansing, MI 48824, USA.
authors.forename: J B
authors.initials: JB
authors.lastname: Matthews
authors.forename: K C
authors.initials: KC
authors.lastname: Fertuck
authors.forename: T
authors.initials: T
authors.lastname: Celius
authors.forename: Y-W
authors.initials: YW
authors.lastname: Huang
authors.forename: C J
authors.initials: CJ
authors.lastname: Fong
authors.forename: T R
authors.initials: TR
authors.lastname: Zacharewski
mesh_terms: D000818:Animals; D004268:DNA-Binding Proteins; D004958:Estradiol / Q000737:chemistry / Q000378:metabolism*; D004965:Estrogen Antagonists / Q000378:metabolism*; D020847:Estrogen Receptor Modulators / Q000378:metabolism*; D004968:Estrogens, Non-Steroidal / Q000494:pharmacology*; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006801:Humans; D015394:Molecular Structure; D051958:Nuclear Receptor Coactivator 2; D011960:Receptors, Estrogen / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D013223:Statistics as Topic; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured
chemical_list: D004268:DNA-Binding Proteins; D004965:Estrogen Antagonists; D020847:Estrogen Receptor Modulators; D004968:Estrogens, Non-Steroidal; C052130:GAL4 protein, S cerevisiae; D051958:Nuclear Receptor Coactivator 2; D011960:Receptors, Estrogen; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D004958:Estradiol