内源性逆转录病毒基因Np9在人白血病细胞中的转录调控机制研究

项目名称： 内源性逆转录病毒基因Np9在人白血病细胞中的转录调控机制研究

项目编号： No.81500115

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 医药、卫生

项目作者： 陈婷

作者单位： 浙江大学

项目金额： 18万元

中文摘要： HERV-K(人内源性逆转录病毒K)Np9基因在肿瘤细胞中呈特异性转录激活。新近，申请人所在团队在国际上率先证明Np9基因在白血病细胞中呈高转录激活状态。其编码的蛋白在56%的白血病患者中高表达，而在正常人样本中几乎不表达，并且该基因的激活能显著促进白血病细胞的增殖。然而，Np9基因在白血病细胞中是如何被转录激活迄今仍未明确。已知HERV-K前病毒5'LTR（长末端重复序列）被认为含有增强和起始转录的有效元件，并且在黑色素瘤细胞中，启动子通过去甲基化后被激活转录。申请人已从白血病细胞K562中获得Np9前病毒5'LTR，并用去甲基化试剂5-Aza-dC处理细胞，发现Np9的转录水平得到显著上调。因此，申请人拟在此基础上寻找白血病细胞中Np9启动子核心区域、鉴定关键转录因子、分析转录因子结合位点甲基化程度及揭示甲基化对启动子活性的影响，为探索白血病病毒病因学提供全新思路。

中文关键词： 白血病；人内源性逆转录病毒K；Np9；转录调控；去甲基化

英文摘要： The viral Np9 transcript, encoded by HERV-K type 1, has been shown to be exclusively present in tumor cells. Recently, we identified that the native Np9 protein was highly expressed in 56% of leukemia patients but rarely detected in normal blood cells. Moreover, the expression of Np9 significantly promoted the growth of human myeloid and lymphoblastic leukemia cells. However, the mechanism for activation of Np9 transcription in leukemia has hitherto vaguely understood. It was reported that the 5'LTR of HERV-K proviruse contained the promoter and enhancing elements. Besides, an early study noted the CpG methylation directly regulated transcriptional activity of HERV-K in melanoma cells. We recently obtained the sequences of HERV-K Np9 5'LTR from K562 cells which had high content of Np9 protein. Furthermore, we used demethylating agent 5-Aza-dC to treat K562 cells and found strong increase of Np9 mRNA by Real-time PCR. Based on these previous studies, we sought to indentify the core region of Np9 promoter, the specific transcription factors and reveal that how methylation regulate the binding of transcription factors on promoter, which shall provide new ideas for the correlation between HERV-K Np9 and leukemia pathogenesis.

英文关键词： Leukemia;HERV-K;Np9;transcriptional regulation;demethylation