Abstract
Ah receptor (AhR) is a ligand-activated transcription factor that mediates pleiotropic effects of environmental pollutants such as 2,3, 7,8-tetrachlorodibenzo-p-dioxin on host animals. In addition to induction of drug-metabolizing enzymes, the liganded AhR complex was found to activate gene expression of a factor designated AhR repressor (AhRR), which inhibits AhR function by competing with AhR for dimerizing with Arnt and binding to the XRE sequence. Thus, AhR and AhRR form a regulatory circuit in the xenobiotic signal transduction pathway and provide a novel mechanism of regulation of AhR function that may determine tissue-specific sensitivity to environmental pollutants.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Aryl Hydrocarbon Receptor Nuclear Translocator
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Basic Helix-Loop-Helix Transcription Factors
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Cloning, Molecular
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DNA-Binding Proteins*
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Dimerization
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Gene Expression Regulation / genetics*
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Helix-Loop-Helix Motifs / genetics
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Mice
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Molecular Sequence Data
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Polychlorinated Dibenzodioxins / metabolism
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Promoter Regions, Genetic / genetics
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Protein Binding / genetics
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Receptors, Aryl Hydrocarbon / metabolism*
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Recombinant Fusion Proteins / genetics
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Repressor Proteins / chemistry
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Repressor Proteins / genetics*
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Sequence Analysis, DNA
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Sequence Homology, Amino Acid
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Transcription Factors / genetics
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Transcription Factors / metabolism
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Transcriptional Activation / genetics
Substances
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Ahrr protein, mouse
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Arnt protein, mouse
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Basic Helix-Loop-Helix Transcription Factors
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DNA-Binding Proteins
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Polychlorinated Dibenzodioxins
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Receptors, Aryl Hydrocarbon
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Recombinant Fusion Proteins
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Repressor Proteins
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Transcription Factors
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Aryl Hydrocarbon Receptor Nuclear Translocator