Repair of alkylation DNA damage

修复烷基化DNA损伤

• 批准号: 09044350
• 负责人: SEKIGUCHI Mutsuo
• 金额: $ 1.22万
• 依托单位: Fukuoka Dental College
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 无数据
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09044350/
• 关键词: alkylating agent; modified base; monoclonal antibody; gene-defective mouse; DNA repair; repair methyltransferase; gene targeting; O^6-methylguanine

Gene targeting was used to obtain mice defective in the MGMT gene, encoding O^6 -methylguanine-DNA methyltransferase. These MGMT^+ mice were most sensitive to the alkylating carcinogen, methylnitrosourea (MNU) ; when varied doses of MNU were administered to 6-week-old mice and survivals at the 30th day were determined, LD_<50S> of MGMT^+ and MGMT^<+/+> mice were 20 and 240 mg/kg of body weight, respectively.MGMT^<+/-> mice were as resistant as MGMT^<+/+> mice, but some difference in survival time was noted when the two genotypes of mice were exposed to a relatively high dose of MNU.A large number of thymic lymphomas, as well as lung adenomas, occurred in MGMT^<-/-> mice exposed to MNU at a dose of 2.5 mg/kg of body weight. In case of exposure to the same dose of drub, no or few tumors occureed in the MGMT^<+/+> and MGMT^<+/-> mice. It appears that the DNA repair methyltransferase protein protected these mice from MNU-induced tumorigenesis.To pursue the fate ot O^6-methylguanin produced in the DNA of mouse tissues, we used monoclonal antibodies raised by the Rajewsky's group of University of Essen. This antibody preparation specifically recognizes O^6-ethylguanine as well as O^6-methylguanin. For the collaborative work, H.Hayakawa and K.Sakumi of Kyushu University visited the Essen laboratory and T.Schweer of Essen visited here in Fukuoka. We have established appropriate doses of MNU to be given to MGMT^<+/+> and MGMT^<-/-> mice and also conditions and procedures to follow changes in amounts of methylated bases in mouse tissues. A preliminary result indicates that MGMT^<-/-> mice retain a significant level of alkylated bases in DNA whereas MGMT^<+/+> mice lose these bases rather quickly.

基因靶向被用来获得MGMT基因缺陷的小鼠，该基因编码O^6 -甲基鸟嘌呤-DNA甲基转移酶。这些MGMT^+小鼠对烷化剂甲基亚硝基脲（MNU）最敏感;当对6周龄小鼠给予不同剂量的MNU并测定第30天的存活率时，<50S>MGMT^+和MGMT^&lt;+/+&gt;小鼠的LD_分别为20和240 mg/kg体重。MGMT^&lt;+/-&gt;小鼠与MGMT^&lt;+/+&gt;小鼠一样具有抗性，MNU剂量为2.5 mg/kg时，MGMT^-/-&gt;小鼠出现大量胸腺淋巴瘤和肺腺瘤。MGMT^&lt;+/+&gt;和MGMT^&lt;+/-&gt;小鼠在相同剂量的药物作用下，无肿瘤发生或很少发生肿瘤。为了研究小鼠组织DNA中产生的O^6-甲基鸟嘌呤的命运，我们使用了由埃森大学的Raidersky小组提出的单克隆抗体。该抗体制剂特异性识别O^6-乙基鸟嘌呤以及O^6-甲基鸟嘌呤。九州大学的H.Hayakawa和K.Sakumi访问了埃森实验室，埃森的T.Schweer访问了福冈。我们已经确定了给予MGMT^&lt;+/+&gt;和MGMT^&lt;-/-&gt;小鼠的MNU的适当剂量，以及跟踪小鼠组织中甲基化碱基量变化的条件和程序。初步结果表明，MGMT^&lt;-/-&gt;小鼠在DNA中保留了显著水平的烷基化碱基，而MGMT^&lt;+/+&gt;小鼠相当快地失去了这些碱基。

项目成果

Y.Tominaga, T.Tsuzuki, A.Shiraishi, H.Kawate and M.Sekiguchi: "Alkylation-induced apoptosis of embryonic stem cells in which the gene for DNA repair methyltransferase had been disrupted by gene targeting" Carcinogenesis. 18. 889-896 (1997)

Y.Tominaga、T.Tsuzuki、A.Shiraishi、H.Kawate 和 M.Sekiguchi：“烷基化诱导的胚胎干细胞凋亡，其中 DNA 修复甲基转移酶基因已被基因靶向破坏”致癌作用。

M.Sekiguchi et al.: "Roles of DNA repair methyltransferase in mutagenesis and enreinogenesis" Jpn.J.Human Genet.42. 389-399 (1997)

M.Sekiguchi 等人：“DNA 修复甲基转移酶在诱变和 enreinogenesis 中的作用”Jpn.J.Human Genet.42。

Y.Tominaga et al.: "Alkylntion-induced npoptonin of ES celln in which the gone for DNA repair methy ltransferase had been disrupted by gone targeting" Carcinogenesis. 18. 889-896 (1997)

Y.Tominaga 等人：“烷基化诱导的 ES 细胞 npoptonin，其中用于 DNA 修复的甲基转移酶已被靶向性破坏”致癌作用。

T.Iwakumn et al.: "High ineidence of nitrosamine-induced tumorigenesis in mico lacking DNA repair methyltransferase" Carcinogenesis. 18. 1631-1635 (1997)

T.Iwakumn 等人：“在缺乏 DNA 修复甲基转移酶的小鼠中亚硝胺诱导的肿瘤发生具有很高的发生率”致癌作用。

M.Sekiguchi and K.Sakumi: "Roles of DNA repair methyltransferase in mutagenesis and carcinogenesis" Japan.J.Human Genet. 42. 389-399 (1997)

M.Sekiguchi 和 K.Sakumi：“DNA 修复甲基转移酶在突变和癌变中的作用”Japan.J.Human Genet。