The Sp family of transcription factors in the regulation of the human and mouse MUC2 gene promoters.
The Sp family of transcription factors in the regulation of the human and mouse MUC2 gene promoters.
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发表时间：
2001
期刊：
影响因子：
11.2
通讯作者：
Fauzia Aslam;L. Palumbo;L. Augenlicht;A. Velcich
中科院分区：
文献类型：
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作者：
Fauzia Aslam;L. Palumbo;L. Augenlicht;A. Velcich
粘蛋白基因表达的调节是结肠癌发展的早期阶段和后期肿瘤进展的重要组成部分。我们实验室和其他人之前的工作表明转录因子 Sp 家族可能在人类 MUC2 基因的调节中发挥重要作用。为了确定这是否是一个必需元素，我们将工作扩展到小鼠 Muc2 (mMuc2) 基因 5' 侧翼区域 3.5 kb 的克隆和分析。小鼠和人类MUC2启动子区域之间的比较分析发现，小鼠和人类基因之间存在很强的序列同源性，包括富含GC的盒的存在，其位置和组成在小鼠和人类基因中得以维持。我们证明这些 GC 盒是 Sp 家族转录因子的结合位点，并且具有重要的功能，因为 Sp1/Sp3 结合抑制剂光神霉素可阻断 HT29 细胞中的 MUC2 基因表达。此外，通过凝胶位移分析和定点诱变的结合，我们已经确定了各个GC盒及其结合因子对小鼠Muc2启动子调节的相对贡献，这在小鼠和人类基因中似乎是不同的。最后，我们通过过表达 Sp1 和 Sp3 证明，两个物种中 MUC2 基因的近端启动子区域之间的功能差异并非归因于该区域结合转录因子 Sp 家族成员的能力差异，而是归因于小鼠和人类近端启动子中各个 GC 盒的不同解剖结构。
Modulation of mucin gene expression is an important component both in the early steps of colon cancer development and in later tumor progression. Previous work from our laboratory and others has suggested that the Sp family of transcription factors may play an important role in the regulation of the human MUC2 gene. To determine whether this was an essential element, we extended our work to the cloning and analysis of 3.5 kb of the 5'-flanking region of the mouse Muc2 (mMuc2) gene. Comparative analysis between the mouse and human MUC2 promoter regions has identified a strong sequence homology between the mouse and human genes, including the presence of GC-rich boxes, the location and composition of which are maintained in the mouse and human genes. We show that these GC boxes are binding sites for Sp-family transcription factors and are functionally important since mithramycin, an inhibitor of Sp1/Sp3 binding, blocks MUC2 gene expression in HT29 cells. Furthermore, by a combination of gel shift analysis and site-directed mutagenesis, we have identified the relative contribution of individual GC boxes, and of the factors they bind, to the regulation of the mouse Muc2 promoter, which appears to be different in the mouse and human genes. Finally, we demonstrate by overexpressing Sp1 and Sp3 that the functional difference between the proximal promoter region of the MUC2 gene in the two species is not attributable to differential ability of this region to bind members of the Sp family of transcription factors, but rather to the different anatomy of the individual GC boxes in the mouse and human proximal promoters.