Structure and expression of the Ah receptor repressor gene
Structure and expression of the Ah receptor repressor gene
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DOI：
10.1074/jbc.m011497200
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发表时间：
2001-08-31
影响因子：
4.8
通讯作者：
Fujii-Kuriyama, Y
中科院分区：
文献类型：
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作者：
Baba, T;Mimura, J;Fujii-Kuriyama, Y
芳烃受体（AhR）阻遏物（AhRR）基因已从小鼠基因组文库中分离并表征。该基因由11个外显子组成，全长约60对。荧光原位杂交分析表明，AhRR基因位于小鼠染色体13 C2，大鼠染色体1p11.2和人类染色体5p15.3。AhRR基因有一个TATA少启动子和几个转录起始位点。此外，在AhRR基因的5 '-上游区域中已经鉴定了推定的调控DNA序列，例如异生素反应元件（XRE）、GC盒和NF-κ B结合位点。瞬时转染HeLa细胞的报告基因，含有缺失和点突变的AhRR启动子的分析表明，所有三个XRE介导的诱导表达的AhRR基因的3-甲基胆蒽治疗，此外，GC盒序列是不可缺少的高水平的诱导表达和组成型表达。此外，通过使用凝胶迁移率变动测定，我们能够显示AhR/Arnt异二聚体以非常低的亲和力结合XRE，这是由于XRE核心序列外的三个不同的核苷酸。我们还发现Sp1和Sp3可以与GC盒结合。最后，瞬时转染分析和凝胶迁移率变动测定都表明，当细胞暴露于12-O-十四烷酰基佛波醇-13-乙酸酯时，AhRR基因被与NF-kappaB位点结合的p65/p50异二聚体上调，并且这种诱导表达通过12-O-十四烷酰基佛波醇-13-乙酸酯和3-甲基胆蒽的共同处理进一步增强。
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-kappaB-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 nucleotides 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-kappaB site when the cells has been exposed to 12-O-tetradecanoylphorbol-13-acetate, and this inducible expression was further enhanced by cotreatment of 12-O-tetradecanoylphorbol-13-acetate and 3-methylcholanthrene.