Transcription of human zinc finger ZNF268 gene requires an intragenic promoter element
Transcription of human zinc finger ZNF268 gene requires an intragenic promoter element
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人锌指 ZNF268 基因的转录需要基因内启动子元件
DOI：
10.1074/jbc.m602753200
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发表时间：
2006-08-25
影响因子：
4.8
通讯作者：
Li, Wen-Xin
中科院分区：
文献类型：
--
作者：
Guo, Ming-Xiong;Wang, Di;Li, Wen-Xin
人ZNF 268基因是一个典型的Kruppel相关盒/C2 H2锌指基因，其同源基因仅在高等哺乳动物中发现，在低等哺乳动物如小鼠中尚未发现。其表达谱表明其在早期人类胚胎发育过程中的血细胞分化和白血病的发病机制中起作用。为了进一步了解控制ZNF 268基因表达的分子机制，并为进一步的白血病遗传学研究提供必要的工具，我们通过逆转录-PCR和引物延伸分析绘制了人ZNF 268 mRNA的5 '端。我们克隆了ZNF 268基因启动子的5 '侧翼基因组DNA，并在几种不同的人和小鼠组织培养细胞系中分析了其功能。有趣的是，我们的研究表明，ZNF 268基因缺乏一个典型的真核启动子，存在于转录起始位点的上游，并指导基础水平的转录。相反，功能性启动子需要位于基因的第一外显子内的必需元件。缺失和突变分析揭示了启动子功能在该元件内需要cAMP反应元件结合蛋白（CREB）结合位点。凝胶迁移率变化和染色质免疫沉淀试验证实，CREB-2结合的网站在体外和体内。此外，CREB-2的过表达增强了启动子活性。这些结果表明，人类ZNF 268基因启动子是非典型的，需要位于第一个外显子内的基因内元件介导CREB对其活性的影响。
Human ZNF268 gene is a typical Kruppel-associated box/C2H2 zinc finger gene whose homolog has been found only in higher mammals and not in lower mammals such as mouse. Its expression profiles have suggested that it plays a role in the differentiation of blood cells during early human embryonic development and the pathogenesis of leukemia. To gain additional insight into the molecular mechanisms controlling the expression of the ZNF268 gene and to provide the necessary tools for further genetic studies of leukemia, we have mapped the 5'-end of the human ZNF268 mRNA by reverse transcription-PCR and primer extension assays. We then cloned the 5'-flanking genomic-DNA-containing the putative ZNF268 gene promoter and analyzed its function in several different human and mouse tissue culture cell lines. Interestingly, our studies show that the ZNF268 gene lacks a typical eukaryotic promoter that is present upstream of the transcription start site and directs a basal level of transcription. Instead, the functional promoter requires an essential element that is located within the first exon of the gene. Deletion and mutational analysis reveals the requirement for a cAMP response-element-binding protein (CREB)-binding site within this element for promoter function. Gel mobility shift and chromatin immunoprecipitation assays confirm that CREB-2 binds to the site in vitro and in vivo. Furthermore, overexpression of CREB-2 enhances the promoter activity. These results demonstrate that the human ZNF268 gene promoter is atypical and requires an intragenic element located within the first exon that mediates the effect of CREB for its activity.