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关于DNA甲基化在肿瘤中的作用的研究 ,大多集中在研究已知的抑癌基因启动子区的异常高甲基化。而一些未知的参与肿瘤发生的基因也可能受甲基化调控 ,寻找这些与肿瘤相关的基因 ,对深入了解肿瘤发生的机制具有重要意义。利用甲基化敏感性随机引物PCR(Methylation SensitiveArbitrarilyPrimedPCR ,MS AP PCR) ,检查了肺癌组织中基因组范围内CpG岛高甲基化情况 ,分离到 8个高甲基化片段 (hypermethylatedDNAfragment,HMDF)。通过克隆、测序和Blast、NewCpGseek软件分析 ,发现所有的片段均为典型的CpG岛 ,有 4个片段与人 2、7、9、10号染色体上的同源性为 99%～ 10 0 % ,但只有 1个是已知的基因。进一步利用NeuralNetworkPromoterPrediction、TSSG和TSSW等软件对其余 7个片段可能的生物学意义进行了分析 ,结果有 4个片段是候选的启动子区 ,提示它们可能源于新基因。所获得的高甲基化片段可能是中国人肺癌发生过程中特有的表遗传学改变。
Much of the work on the role of DNA methylation in tumors has focused on the abnormal hypermethylation of the known tumor suppressor gene promoter regions. However, some unknown genes involved in tumorigenesis may also be regulated by methylation. Looking for these tumor-related genes is of great significance for understanding the mechanism of tumorigenesis. Genome-wide CpG island hypermethylation in lung cancer tissues was examined using methylation-sensitive random primers PCR (MSAP PCR). Eight hypermethylated DNA fragments (HMDFs) were isolated. Through cloning, sequencing and Blast, NewCpGseek software analysis, all the fragments were found to be typical CpG islands, with 4 fragments of 99% ~ 100% homology with chromosomes 2, 7, 9 and 10, But only one is a known gene. Furthermore, the possible biological significance of the remaining seven fragments was analyzed by using software such as NeuralNetPromoterPrediction, TSSG and TSSW. As a result, four fragments were candidate promoter regions, suggesting that they may be derived from new genes. The obtained hypermethylated fragment may be a characteristic epigenetic change in Chinese lung cancer.