Study on repair mechanism of DMA double-strand breaks induced by ionizing radiation using a gene targeting technique

基因打靶技术研究电离辐射诱导的DMA双链断裂修复机制

• 批准号: 14580560
• 负责人: TAUCHI Hiroshi
• 金额: $ 2.3万
• 依托单位: IBARAKI UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14580560/
• 关键词: DNA repair; Homologous recombination; Ionizing radiation; Genome instability-; Gene targeting

DNA double-strand break (DSB), which is often induced by ionizing radiation, is the most serious damage in genome. There are at least two pathways which can repair DSBs : non-homologous end joining (NHEJ} and homologous recombination (HR). Nbs1 is the underlying gene for Nijmegen breakage syndrome, and is reported to be a regulator of the both biochemical activity and localization of Rad50/Mre11 complex. We established an Nbs1 knockout cell line by using the chicken DT4o cells in order to investigate the role of the Rad50/Mre11/Nbs1 complex in DSB repair pathway in vertebrate cells. The disruption of Nbs1 reduces gene conversion and sister chromatid exchanges, similar to other HR-deficient mutants, in contrast to their almost normal NHEJ efficiency. A site-specific DSB repair assay using SCneo reporter showed a remarkable reduction of HR events following DSB generation in Nbs1-disrupted cells. The rare recombinants observed in the Nbs1-disrupted cells were frequently found to have aberrant structures, which are possibly arise from an unusual crossover events, suggesting that the Nbs1 complex might be required to process recombination intermediates

DNA双链断裂（DSB）是基因组中最严重的损伤，通常由电离辐射引起。至少有两种途径可以修复dsb：非同源末端连接（NHEJ）和同源重组（HR）。Nbs1是奈亨断裂综合征的潜在基因，据报道是Rad50/Mre11复合物生化活性和定位的调节因子。为了研究Rad50/Mre11/Nbs1复合物在脊椎动物细胞DSB修复通路中的作用，我们利用鸡dt40细胞建立了Nbs1敲除细胞系。与几乎正常的NHEJ效率相反，Nbs1的破坏减少了基因转换和姐妹染色单体交换，类似于其他hr缺陷突变体。使用SCneo报告基因的位点特异性DSB修复实验显示，在nbs1破坏的细胞中产生DSB后，HR事件显著减少。在Nbs1破坏的细胞中观察到的罕见重组体经常被发现具有异常的结构，这可能是由不寻常的交叉事件引起的，这表明Nbs1复合体可能需要处理重组中间体

项目成果

Tauchi, H., et al.: "Nijmegen breakage syndrome gene, NBS1, and molecular links to factors for genome stability"Oncogene. 21. 8967-8680 (2002)

Tauchi, H. 等人：“奈梅亨断裂综合征基因、NBS1 以及与基因组稳定性因素的分子联系”癌基因。

Tauchi, H.: "Nijmegen breakage syndrome gene, NBS1, and molecular links to factors for genome stability"Oncogene. 21. 8967-8980 (2002)

Tauchi, H.：“奈梅亨断裂综合征基因、NBS1 以及与基因组稳定性因素的分子联系”癌基因。

Hama, S.: "p16 gene transfer increases cell killing with abnormal nucleation after ionizing radiation in glioma cells"British Journal of cancer. 89. 1802-1811 (2003)

Hama, S.：“p16 基因转移增加了神经胶质瘤细胞电离辐射后异常成核的细胞杀伤作用”《英国癌症杂志》。

Hama, S. 他: "p16 gene transfer increases cell killing with abnormal nucleation after ionizing radiation in glioma cells"British Journal of Cancer. 89. 1802-1811 (2003)

Hama, S. 等人：“p16 基因转移增加了神经胶质瘤细胞中电离辐射后异常成核的细胞杀伤”英国癌症杂志 89. 1802-1811 (2003)。

Tauchi H.: "Nbs1 is essential for DNA repair by homologous recombination in higher vertebrate cells"Nature. 420 No.6911. 93-98 (2002)

Tauchi H.：“Nbs1 对于高等脊椎动物细胞中通过同源重组进行 DNA 修复至关重要”。