title: Development of yeast reporter assays for the enhanced detection of environmental ligands of thyroid hormone receptors α and β from Xenopus tropicalis.
abstract: Thyroid hormones (THs) are involved in the regulation of metabolic homeostasis during the development and differentiation of vertebrates, particularly amphibian metamorphosis, which is entirely controlled by internal TH levels. Some artificial chemicals have been shown to exhibit TH-disrupting activities. In order to detect TH disruptors for amphibians, we herein developed a reporter assay using yeast strains expressing the thyroid hormone receptors (TRs) α and β together with the transcriptional coactivator SRC-1, all of which were derived from the frog Xenopus tropicalis (XT). These yeast strains responded to endogenous THs (T2, T3, and T4) in a dose-dependent manner. They detected the TR ligand activities of some artificial chemicals suspected to exhibit TH-disrupting activities, as well as TR ligand activity in river water collected downstream of sewage plant discharges, which may have originated from human excrement. Moreover, the responses of XT TR strains to these endogenous and artificial ligands were stronger than those of yeast strains for human TRα and β assays, which had previously been established in our laboratory. These results indicate that the yeast reporter assay system for XT TRα and β is valuable for assessing TR ligand activities in environmental samples that may be particularly potent in amphibians.
authors.affiliation: Department of Biology, Graduate School of Science, Osaka Prefecture University, Naka-ku, Sakai, Osaka 599-8570, Japan.
authors.forename: Satoko
authors.initials: S
authors.lastname: Matsui
authors.affiliation: Department of Biology, Graduate School of Science, Osaka Prefecture University, Naka-ku, Sakai, Osaka 599-8570, Japan.
authors.forename: Sayoko
authors.initials: S
authors.lastname: Ito-Harashima
authors.affiliation: Department of Biology, Graduate School of Science, Osaka Prefecture University, Naka-ku, Sakai, Osaka 599-8570, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Sugimoto
authors.affiliation: Department of Biology, Graduate School of Science, Osaka Prefecture University, Naka-ku, Sakai, Osaka 599-8570, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Takada
authors.affiliation: Department of Biology, Graduate School of Science, Osaka Prefecture University, Naka-ku, Sakai, Osaka 599-8570, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Shiizaki
authors.affiliation: Department of Biology, Graduate School of Science, Osaka Prefecture University, Naka-ku, Sakai, Osaka 599-8570, Japan.
authors.forename: Masanobu
authors.initials: M
authors.lastname: Kawanishi
authors.affiliation: Department of Biology, Graduate School of Science, Osaka Prefecture University, Naka-ku, Sakai, Osaka 599-8570, Japan; Department of Life Science, Dongguk University, Jung-gu, Seoul 100-715, Republic of Korea. Electronic address: yagi-t@riast.osakafu-u.ac.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yagi
mesh_terms: D000818:Animals; D018076:DNA, Complementary / Q000235:genetics; D005243:Feces / Q000737:chemistry; D017930:Genes, Reporter; D006801:Humans; D008024:Ligands; D056920:Nuclear Receptor Coactivator 1 / Q000235:genetics / Q000378:metabolism; D010957:Plasmids; D045483:Rivers / Q000737:chemistry; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D037021:Thyroid Hormone Receptors alpha / Q000235:genetics / Q000378:metabolism; D037042:Thyroid Hormone Receptors beta / Q000235:genetics / Q000378:metabolism; D013963:Thyroid Hormones / Q000378:metabolism; D014556:Urine / Q000737:chemistry; D014981:Xenopus / Q000235:genetics*
chemical_list: D018076:DNA, Complementary; D008024:Ligands; D037021:Thyroid Hormone Receptors alpha; D037042:Thyroid Hormone Receptors beta; D013963:Thyroid Hormones; D056920:Nuclear Receptor Coactivator 1
keywords: Amphibian metamorphosis; Endocrine-disrupting substance; Thyroid hormone; Water pollutant; Yeast reporter assay