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目的脑胶质母细胞瘤(glioblastoma,GBM)中存在广泛的基因组低甲基化,本研究检查了DNA甲基化转移酶3B(DNA methyltransferase 3B,DMNT3B)是否在这种肿瘤中的表达和突变情况,以期寻找肿瘤基因组低甲基化发生的原因。方法用RNA抽提试剂盒从25例人脑胶质母细胞瘤组织中提取总RNA,用反转录聚合酶链反应方法扩增DNMT3B的cDNA,然后测序,所得序列经DNASTAR软件与NCBI发表的正常序列进行比对。结果从25例脑胶质母细胞瘤样本中的成功扩增了全长DNMT3B cDNA,测序分析结果显示DNMT3B基因在该肿瘤样本中差异性存在多种剪接变异体,以DNMT3B-V1、DNMT3B-V3、DNMT3B-V7为主。没有发现改变氨基酸序列的点突变。结论 DNMT3B基因在脑胶质母细胞瘤中没有点突变,但存在多种剪接变异体(以DNMT3B-V3、DNMT3B-V7为主),其是否为脑胶质母细胞瘤的广泛基因组低甲基化的原因尚有待进一步研究。
There is a wide range of genomic hypomethylation in glioblastoma (GBM). This study examined whether DNA methyltransferase 3B (DMNT3B) is expressed and mutated in this tumor In order to find the cause of tumor hypomethylation. Methods Total RNA was extracted from 25 human glioblastoma tissues by RNA extraction kit. The cDNA of DNMT3B was amplified by reverse transcription-polymerase chain reaction (RT-PCR), and sequenced. The DNA sequence was obtained by DNASTAR software and published by NCBI Normal sequence alignment. Results The full-length DNMT3B cDNA was amplified successfully from 25 samples of glioblastoma. The results of sequencing showed that DNMT3B gene had many different splice variants in this sample. DNMT3B-V1, DNMT3B-V3 , DNMT3B-V7-based. No point mutation was found to change the amino acid sequence. Conclusion DNMT3B gene has no point mutation in glioblastoma, but there are many kinds of splice variants (mainly DNMT3B-V3 and DNMT3B-V7), which are the low genomic methyl groups of glioblastoma The reason for the change remains to be further studied.