Transcriptional activation of the MUC2 gene by p53
Transcriptional activation of the MUC2 gene by p53
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DOI：
10.1074/jbc.m207986200
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发表时间：
2002-12-13
影响因子：
4.8
通讯作者：
Tsuchida, S
中科院分区：
文献类型：
--
作者：
Ookawa, K;Kudo, T;Tsuchida, S
MUC 2是在上皮表面和肠腔之间提供保护屏障的粘蛋白的主要组分之一。我们研究了p53和p21（Sdi 1/Waf 1/Cip 1）在人结肠癌细胞系DLD-1中MUC 2基因表达的可能改变，建立了四环素可调控启动子控制外源性p53和p21的亚克隆。表情MUC 2 mRNA对p53的反应比对p21的反应更显著。出乎意料的是，MUC 2表达也诱导人骨肉瘤细胞，U-2 OS和Saos-2，外源性p53。我们接下来进行了报告基因测定以测试p53对MUC 2基因表达的直接调节。MUC 2启动子区的缺失和突变表明，它含有两个由p53反式激活的位点。此外，电泳迁移率变动分析表明，p53结合这些元素。我们分析了MUC 2在其他细胞类型中的表达，这些细胞在暴露于各种形式的应激后具有功能性p53。在MCF 7乳腺癌和A427肺癌细胞中，MUC 2表达随着放线菌素D、UVC和X射线引起的内源性p53水平沿着增加，但在携带突变的p53的RERF-LC-MS肺癌细胞中没有。这些结果表明，p53在许多细胞类型中直接激活MUC 2基因。
MUC2 is one of the major components of mucins that provide a protective barrier between epithelial surfaces and the gut lumen. We investigated possible alterations of MUC2 gene expression by p53 and p21(Sdi1/Waf1/Cip1) in a human colon cancer cell line, DLD-1, establishing subclones in which a tetracycline-regulatable promoter controls exogenous p53 and p21. expression. MUC2 mRNA more significantly increased in response to p53 than to p21. Unexpectedly, MUC2 expression was also induced in human osteosarcoma cells, U-2OS and Saos-2, by exogenous p53. We next performed a reporter assay to test the direct regulation of MUC2 gene expression by p53. Deletion and mutagenesis of the MUC2 promoter region showed that it contains two sites for transactivation by p53. Furthermore, an electrophoretic mobility shift assay indicated that p53 binds to those elements. We analyzed MUC2 expression in other cell types possessing a functional p53 after exposure to various forms of stress. In MCF7 breast cancer and A427 lung cancer cells, MUC2 expression was increased along with the endogenous p53 level by actinomycin D, UVC, and x-ray, but not in RERF-LC-MS lung cancer cells carrying a mutated p53. These results suggest that p53 directly activates the MUC2 gene in many cell types.