title: Recombinant aryl hydrocarbon receptors for bioassay of aryl hydrocarbon receptor ligands in transgenic tobacco plants.
abstract: Dioxin residues widely contaminate soil and agricultural products at low concentrations and may accumulate in organisms at the top of food chains owing to their physicochemical properties. In this study, we have developed novel, dioxin-inducible, reporter gene expression systems regulated by recombinant aryl hydrocarbon receptors (AhRs). The recombinant AhRs, referred to as XDVs, consist of the DNA-binding domain of the bacterial repressor protein LexA, a 90-kDa heat shock protein- and ligand-binding regulatory domain from mouse AhR, and the transactivation domain of herpes simplex virus regulatory protein VP16. Transgenic tobacco plants carrying XDVs absorb various AhR ligands, including 3-methylcholanthrene, beta-naphthoflavone and indigo from solid medium and vermiculite, and show dose- and time-dependent expression of the beta-glucuronidase reporter gene. The results clearly suggest that XDVs are functional transcription factors that respond to AhR ligands, and that the XDV-mediated reporter gene expression system is applicable to bioassays for dioxin residues in the environment.
authors.affiliation: Graduate School of Science and Technology, Kobe University, Rokkodai-cho 1-1, Nada-ku, Kobe 657-8501, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Kodama
authors.forename: Kumiko
authors.initials: K
authors.lastname: Okada
authors.forename: Keiko
authors.initials: K
authors.lastname: Akimoto
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Inui
authors.forename: Hideo
authors.initials: H
authors.lastname: Ohkawa
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D004147:Dioxins / Q000378:metabolism; D015870:Gene Expression; D017930:Genes, Reporter; D007203:Indigo Carmine; D007211:Indoles / Q000378:metabolism; D008024:Ligands; D008748:Methylcholanthrene / Q000378:metabolism; D051379:Mice; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D018336:Receptors, Aryl Hydrocarbon / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D019324:beta-Naphthoflavone / Q000378:metabolism; D000099160:LexA Repressor Protein
chemical_list: D001426:Bacterial Proteins; D004147:Dioxins; D007203:Indigo Carmine; D007211:Indoles; D008024:Ligands; D008748:Methylcholanthrene; D018336:Receptors, Aryl Hydrocarbon; D011994:Recombinant Proteins; D012697:Serine Endopeptidases; D014157:Transcription Factors; D019324:beta-Naphthoflavone; D000099160:LexA Repressor Protein