G-Quadruplex Structures at the Promoter of HOXC10 Regulate its Expression
G-Quadruplex Structures at the Promoter of HOXC10 Regulate its Expression
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HOXC10启动子处的G-四链体结构调节其表达
DOI：
10.1016/j.bbagrm.2018.09.004
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Sui GC
中科院分区：
文献类型：
--
作者：
Zhang X;Zhao B;Yan T;Hao A;Gao Y;Li D;Sui GC
HOXC 10是同源异型盒基因家族的成员之一，在哺乳动物细胞分化和胚胎发育中起重要作用。越来越多的证据也表明HOXC 10在肿瘤发生中的调节作用，但HOXC 10基因表达的调节相对研究不足。在这份报告中，我们发现HOXC 10启动子在其负链中含有多个G-片段，并且具有形成G-四链体结构的高潜力。在圆二色性研究中，基于HOXC 10转录起始位点上游241-297个碱基对的G-富集区域合成的寡核苷酸在特定波长下表现出G-四链体结构特征的摩尔椭圆率。通过非变性聚丙烯酰胺凝胶电泳、凝胶迁移试验、免疫染色和复制终止试验对这些寡核苷酸进行分析，发现在钾和锂离子存在下形成多种类型的G-四链体结构。在报告基因检测中，G-束的突变或缺失可能会对HOXC 10启动子下游的Gaussia荧光素酶的表达产生差异性影响。此外，CHD 7，一种具有DNA解旋酶活性的染色质重塑蛋白，可以与HOXC 10启动子结合，并可能解开G-四链体结构以增强其基因表达。
As a member of the homeobox gene family, HOXC10 plays an important role in cell differentiation and embryonic development of mammals. Increasing evidence also suggests a regulatory role of HOXC10 in oncogenesis, but the regulation of HOXC10 gene expression is relatively understudied. In this report, we revealed that the HOXC10 promoter contains multiple G-tracts in its negative strand and has high potential of forming G-quadruplex structures. In circular dichroism studies, synthesized oligonucleotides based on the G-rich region of 241–297 base pairs upstream of the HOXC10 transcription start site showed molar ellipticity at specific wavelengths characteristic of G-quadruplex structures. Analyses of these oligonucleotides by native polyacrylamide gel electrophoresis, gel-shift assay, immunostaining and replication stop assay revealed formation of multiple types of G-quadruplex structures in presence of potassium and lithium ions. In reporter assays, mutations or deletion of the G-tracts could differentially impact the expression of Gaussia luciferase downstream of the HOXC10 promoter. Additionally, CHD7, a chromatin remodeling protein with DNA helicase activity, could associate with the HOXC10 promoter and likely unwind the G-quadruplex structures to enhance its gene expression.