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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.

关于极低频磁场（ELFMF）对人体的毒性作用，特别是对肿瘤发生的影响，已有许多肯定或否定的报道，但尚未得出结论。构成人体的细胞遭受DNA的损伤，突变是由诱变物质或现象引起的。众所周知，突变是肿瘤发生的直接原因，细胞的癌变与DNA的分子损伤有着密切的关系，同时，基因工程的发展也取得了显著的成绩，DNA分析的实验技术已被广泛应用于各个科学领域。因此，也可以利用分子生物学技术对ELFMF导入活细胞进行基因水平的研究。当细菌的DNA被某些原因损伤时，SOS修复遗传系统，例如umu操纵子和recA基因，其意图是恢复损伤，被表达。在这项研究中，SOS调节子的表达系统的umu测定方法，阐明了磁场暴露的影响，基因突变的DNA分子的损伤，应用的可能性进行了检查。我们将细菌鼠伤寒沙门氏菌TA 153（pSK 1002）（一种致病性缺失的衍生菌株）暴露于ELFMF，并通过umu测定方法与非暴露对照检查β-半乳糖苷酶酶活性的表达强度，β-半乳糖苷酶是位于umu SOS基因操纵子下游的lacZ基因的产物。实验结果表明，umu检测法可以有效地用于评价ELFMF对DNA分子的损伤，但在实验条件下，umu基因表达强度无显著差异。