Development of molecular bio-dosimeiry and monitor mice for the detection of radiation dose exposed by tritium water

1）辐射敏感的Rev 1转基因小鼠的建立我们鉴定了小鼠和人的Rev 1基因，它是UmuC/DinB/XPV基因家族的成员，在自发突变中起重要作用。小鼠Rev 1蛋白的生化分析显示，小鼠Rev 1蛋白具有与人REV 1蛋白一样的脱氧胞苷酰转移酶活性。辐射诱导小鼠胚胎成纤维细胞表达Revl。在此基础上，我们尝试建立Rev 1转基因小鼠，以建立辐射超敏小鼠模型。我们将携带mRevl的MT-1质粒导入C57 BL小鼠。我们已经有36只携带mRevl的老鼠。2）氚水分子生物剂量学系统的建立在辐射损伤DNA双链修复机制中，Historic H2 AX、Ku 70、Ku 80和Tip 60被认为起着重要作用。我们观察到照射后H2 AX被磷酸化（γ-H2 AX）并形成灶。为了将焦点形成用于DNA双链断裂的剂量测定，我们纯化了组成型H2 AX复合物，并通过MS/MS光谱分析鉴定了其新组分。我们制备了抗这些成分的抗体，并进行了免疫组织化学分析，以检测DNA双链断裂处的病灶。此外，我们发现NBS 1在辐射后定位于γ-H2 AX灶。病灶数与DNA双链断裂的关系正在研究中。

We tried to develop bio-dosimetry system of tritium water at the level from whole body to molecule.1) Development of Revl transgenic mice which are sensitive to radiation exposureWe characterized mouse and human Revl gene which was a member of the UmuC/DinB/XPV gene family, played important roles in spontaneous mutations. Biochemical analysis of the mouse Revl protein revealed that the mouse Revl protein possessed a deoxycytidyl transferase activity as human REV1 protein. The expression of mouse Revl in embryonic fibroblasts was induced by radiation exposure. Based on these knowledge, we try to establish Revl transgenic mouse to develop the hypersensitive mouse model to radiation exposure. We introduced MT-1 plasmid carrying mRevl down stream the metallotuionein promoter into C57BLmice. We already got 36 mice carrying mRevl. We will check the expression of mRevl.2) Development of molecular bio-dosimetry system for tritium waterIn repair machinery of DNA double trand break by radiation, Historic H2AX, Ku70, Ku80 and Tip60 are thought to play an important role. We observed that H2AX was phosphorylated (γ-H2AX) and formed foci after irradiation. In order to use the foci formation for the dosimetry of DNAdouble strand breaks, we purify the constitutive H2AX complex and identify its new components by MS/MS spectrometric analysis. We prepared antibody against these components and performed the immunohistochemical analysis to detect the foci at DNAdouble strand breaks. Furthermore, we found that NBS1 localized toγ-H2AX foci after radiation exposure. Relationship between numbers of foci and DNAdouble strand breaks is under investigation.