Structure and Expression of the Ah Receptor Repressor Gene

Takashi Baba, Junsei Mimura, Katarina Gradin, Asato Kuroiwa, Takafumi Watanabe, Yoichi Matsuda, Johji Inazawa, Kazuhiro Sogawa, Yoshiaki Fujii-Kuriyama

Research output: Contribution to journalArticlepeer-review

133 Citations (Scopus)

Abstract

The aryl hydrocarbon receptor (AhR) repressor (AhRR) gene has been isolated and characterized from a mouse genomic library. The gene is distributed as 11 exons in a total length of about 60 kilobase pairs. Fluorescence in situ hybridization analysis has shown that the AhRR gene is located at mouse chromosome 13C2, at rat chromosome 1p11.2, and at human chromosome 5p15.3. The AhRR gene has a TATA-less promoter and several transcription start sites. In addition, putative regulatory DNA sequences such as xenobiotic responsive element (XRE), GC box, and NF-κB-binding sites have been identified in the 5′-upstream region of the AhRR gene. Transient transfection analyses of HeLa cells with reporter genes that contain deletions and point mutations in the AhRR promoter revealed that all three XREs mediated the inducible expression of the AhRR gene by 3-methylcholanthrene treatment, and furthermore, GC box sequences were indispensable for a high level of inducible expression and for constitutive expression. Moreover, by using gel mobility shift assays we were able to show that the AhR/Arnt heterodimer binds to the XREs with very low affinity, which is due to three varied nncleotides outside the XRE core sequence. We have also shown that Sp1 and Sp3 can bind to the GC boxes. Finally, both transient transfection analysis and gel mobility shift assay revealed that the AhRR gene is up-regulated by a p65/p50 heterodimer that binds to the NF-κB site when the cells has been exposed to 12-O-tetradecanoylphorbol-13-acetate, and this inducible expression was further enhanced by co-treatment of 12-O-tetradecanoylphorbol-13-acetate and 3-methylcholanthrene.

Original languageEnglish
Pages (from-to)33101-33110
Number of pages10
JournalJournal of Biological Chemistry
Volume276
Issue number35
DOIs
Publication statusPublished - Aug 31 2001
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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