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Use of a Bacterial Gene Expression System for Mutation Repairing (umu system) to evaluate Damage in DNA Molecules Resulting from Exposure to an Extra Low Frequency Magnetic Field

使用细菌基因表达系统进行突变修复（umu 系统）来评估因暴露于超低频磁场而导致的 DNA 分子损伤

基本信息

批准号：
10837015
负责人：
HAGA Akira
金额：
$ 2.05万
依托单位：
Tohoku Gakuin University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

Though there are many affirmative or negative reports on affect vicious of extremely low frequency magnetic field (ELFMF) exposure to human body, especially on the effect to oncogenesis, its conclusion has not been reached yet. Cells, which constitute the human body, suffer damage of DNA, and mutation is caused by mutagenic substances or phenomena. It is well known that mutation becomes a direct cause of cancer-developing, and there is a close relation between the oncogenesis of cells and molecular damage of DNA.In a meantime, genetic engineering has been developed remarkably, the experimental technique in DNA analysis has generally been adopted to the many fields of sciences. Therefore the gene level research of the import of the ELFMF exposure to the living cell can also be dove using molecular biological technique. When DNA of bacteria is damaged by some causes, SOS repairing genetic systems, for instance umu operon and recA genes, which intend to restore the damage, are expressed. In this study, the possibility of applying expression system of a SOS regulon by umu assay method, which clarifies the impact of a magnetic field exposure for gene mutation by a damage in DNA molecule, was examined. We exposed bacterium Salmonella typhimurium TA153(pSK1002) (a derivative strain whose pathogenicity was deleted) to ELFMF, and the intensity of the expression of an enzymatic activity of β-galactosidase which is the product of lacZ gene located downstream of the umu SOS gene operon, was examined by umu assay method with a non-exposure control. The experimental results showed that the umu assay could be effectively applied to the evaluation of damage in DNA molecules by exposure to an ELFMF.However, no significant differences were observed in the umu gene expression intensity under experimental condition.

尽管极低频磁场（ELFMF）暴露对人体的恶性影响，特别是对肿瘤发生的影响有很多肯定或否定的报道，但尚未得出结论。构成人体的细胞受到DNA损伤，突变是由诱变物质或现象引起的。众所周知，突变是癌症发生的直接原因，细胞的癌变与DNA的分子损伤有着密切的关系。与此同时，基因工程得到了长足的发展，DNA分析的实验技术已普遍应用于许多科学领域。因此，还可以使用分子生物学技术来进行ELFMF暴露对活细胞的影响的基因水平研究。当细菌的DNA因某种原因受损时，会表达SOS修复遗传系统，例如umu操纵子和recA基因，其目的是恢复损伤。在这项研究中，探讨了通过umu测定方法应用SOS调节子表达系统的可能性，该方法阐明了磁场暴露对DNA分子损伤造成的基因突变的影响。我们将鼠伤寒沙门氏菌TA153（pSK1002）（致病性被删除的衍生菌株）暴露于ELFMF，并通过umu测定方法和非暴露对照检查位于umu SOS基因操纵子下游的lacZ基因产物β-半乳糖苷酶的酶活性的表达强度。实验结果表明，umu检测可以有效地应用于评估ELFMF对DNA分子的损伤。但实验条件下umu基因表达强度没有观察到显着差异。