A functional common polymorphism in a Sp1 recognition site of the epidermal growth factor receptor gene promoter.
A functional common polymorphism in a Sp1 recognition site of the epidermal growth factor receptor gene promoter.
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DOI：
10.1158/0008-5472.46.65.1
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发表时间：
2005-01
期刊：
影响因子：
11.2
通讯作者：
Wanqing Liu;F. Innocenti;Michael H. Wu;A. Desai;M. Dolan;E. Cook;M. Ratain
中科院分区：
文献类型：
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作者：
Wanqing Liu;F. Innocenti;Michael H. Wu;A. Desai;M. Dolan;E. Cook;M. Ratain
表皮生长因子受体（EGFR）在细胞生长和发育中发挥着重要作用。它在人类中的调节是复杂的且不完全清楚。本研究在EGFR基因5'调控区发现了12个新的多态性，在必需启动子区发现了2个常见的单核苷酸多态性（-216G/T和-191C/A），其中一个位于Sp1识别位点（-216）。人类癌症和原代细胞系中的瞬时转染显示两种最常见的单倍型（-216G-191C 和 -216T-191C）之间显着不同的启动子活性。在-216位用T替换G使启动子活性增加30%。 Sp1 缺陷细胞系（Schneider 细胞系 2）中的瞬时转染测定显示 EGFR 启动子活性对 Sp1 的强烈依赖性，并证实了上述多态性的作用。电泳迁移率变动分析还显示，与 G 等位基因相比，核蛋白或纯 Sp1 蛋白与 T 等位基因的结合效率显着更高。然后，我们研究了具有-216G/T杂合基因型但具有-191C/A C/C纯合基因型的成纤维细胞系中EGFR转录的等位基因不平衡。携带T-C单倍型的mRNA表达量明显强于携带G-C单倍型的mRNA（P < 0.02）。因此，我们成功地证明了 EGFR 启动子中常见的多态性与体内外启动子活性和基因表达的改变有关。我们的研究结果对癌症病因学和治疗具有重要意义，也可能与其他常见疾病的遗传易感性有关。
The epidermal growth factor receptor (EGFR) plays a prominent role in cell growth and development. Its regulation in humans is complex and incompletely understood. In this study, 12 new polymorphisms were discovered in the 5'-regulatory region of EGFR gene and 2 common single nucleotide polymorphisms (-216G/T and -191C/A) were found in the essential promoter area, one of which is located in a Sp1 recognition site (-216). Transient transfection in human cancer and primary cell lines showed significantly different promoter activity between the two most common haplotypes (-216G-191C and -216T-191C). The replacement of G by T at position -216 increases the promoter activity by 30%. A transient transfection assay in the Sp1-deficient cell line (Schneider cell line 2) showed a strong dependence of EGFR promoter activity on Sp1 and confirmed the effect of the aforementioned polymorphisms. Electrophoretic mobility shift assay also showed a significantly higher binding efficiency of nuclear protein or pure Sp1 protein to the T allele compared with the G allele. We then investigated the allelic imbalance of EGFR transcription in fibroblast cell lines with heterozygous genotype at -216G/T but C/C homozygous genotype at -191C/A. The expression of mRNA carrying T-C haplotype was significantly stronger compared with that of G-C haplotype (P < 0.02). Thus, we successfully showed that a common polymorphism in the EGFR promoter was associated with altered promoter activity and gene expression both in vitro and in vivo. Our findings have implications for cancer etiology and therapy and may also be relevant to the inherited susceptibility of other common diseases.