A role for intronic sequences on expression of thyroid hormone receptor alpha gene.
A role for intronic sequences on expression of thyroid hormone receptor alpha gene.
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内含子序列对甲状腺激素受体α基因表达的作用。
DOI：
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发表时间：
1994
影响因子：
4.8
通讯作者：
V. Nikodem
中科院分区：
文献类型：
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作者：
J. Lazar;B. Desvergne;E. C. Zimmerman;D. Zimmer;M. Magnuson;V. Nikodem
我们克隆了大鼠甲状腺激素受体α（THR）基因，并对其组织进行了表征。通过RNA引物延伸分析绘制了多个转录起始位点。大鼠THR α基因的启动子不含TATA或CAAT盒。用NIH 3 T3和NG 108 -15细胞对THR α基因5 ′区的缺失分析和转染试验表明，从-137到+205（+205位于第一内含子）的序列是该基因有效表达所必需的。该区域包含两个正作用元件，位于转录主要起始点上游的序列-137至-60和位于第一内含子中的AGG序列的三个拷贝。相反，第一内含子中的两个八聚体结合基序作为负调控元件发挥作用。凝胶迁移率变动分析表明，富含嘌呤的序列和八聚体结合基序结合NIH 3 T3和NG 108 -15细胞中存在的蛋白质，瞬时转染分析中的受体。THR α和β的基因组序列比较揭示了这两个基因中存在富含嘌呤的轨道，而八聚体结合基序仅在α基因中发现。这些结果可能解释了THR α和β基因表达的差异调节。
We have cloned and characterized the organization of the rat thyroid hormone receptor alpha (THR) gene. Multiple transcription start sites were mapped by RNA primer extension analyses. The promoter of the rat THR alpha gene does not contain a TATA or CAAT box. Deletion analyses of the 5' region of THR alpha gene and transfection assays, using NIH3T3 and NG108-15 cells, revealed that the sequences from -137 to +205 (+205 resides in the first intron) are necessary for efficient expression of this gene. This region contains two positively acting elements, the sequence -137 to -60 upstream from the major start of transcription and three copies of an AGG sequence located in the first intron. In contrast, two octamer-binding motifs in the first intron function as the negative regulatory elements. Gel mobility shift assays showed that the purine-rich sequence and the octamer-binding motifs bind to a protein(s) present in NIH3T3 and NG108-15 cells, the recipients in transient transfection assays. Genomic sequence comparison of THR alpha and beta revealed the presence of the purine-rich track in both genes, while the octamer-binding motifs were found only in the alpha gene. These results might explain the differential regulation of THR alpha and beta gene expression previously noted.