Single nucleotide polymorphism analysis and functional characterization of the human Ah receptor (AhR) gene promoter.
The aryl hydrocarbon receptor (AhR) mediates biological and toxicological actions of e.g., halogenated aromatic hydrocarbons such as 2,3,7,8-tetrachlorodibenzo-p-dioxin. Although much is known about the biochemical and molecular mechanisms of AhR action, little is known about the control of the expression of the AhR gene itself. Therefore, we aimed at the identification and characterization of regions important for constitutive AhR gene expression. First, we screened 2.6 kb of the 5(')-flanking region of the AhR gene in 91 healthy Caucasian volunteers for naturally occurring genetic variants. Seven variants were detected. However, they do not seem to influence AhR gene expression in lymphocytes. Using a 2.7 kb AhR promoter luciferase reporter gene construct and various deletion constructs, a putative regulatory region was identified and characterized further by electrophoretic mobility shift assays and site-directed mutagenesis. These investigations were confirmed by cotransfection experiments in Drosophila SL2 cells. The obtained results prove an involvement of Sp1 in AhR gene regulation.
Racky
Judith
J
Food Chemistry and Environmental Toxicology, Technical University of Kaiserslautern, Erwin-Schroedinger-Strasse, D-67663 Kaiserslautern, Germany.
Schmitz
Hans-Joachim
HJ
Kauffmann
Hans-Martin
HM
Schrenk
Dieter
D
D024506:5' Flanking Region / Q000235:genetics; D000818:Animals; D002460:Cell Line; D045744:Cell Line, Tumor; D015331:Cohort Studies; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster; D005260:Female; D017353:Gene Deletion; D015870:Gene Expression; D017930:Genes, Reporter / Q000235:genetics; D005838:Genotype; D006801:Humans; D008156:Luciferases / Q000378:metabolism; D008297:Male; D016297:Mutagenesis, Site-Directed; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic / Q000235:genetics / Q000502:physiology*; D012333:RNA, Messenger / Q000096:biosynthesis; D018336:Receptors, Aryl Hydrocarbon / Q000235:genetics* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics; D014162:Transfection
D017362:Cyclic AMP Response Element-Binding Protein; D012333:RNA, Messenger; D018336:Receptors, Aryl Hydrocarbon; D011994:Recombinant Proteins; D008156:Luciferases