Department of Technical Support and Development, Fundamental Technology Center, National Institute of Radiological Sciences.
J Radiat Res. 2011;52(4):433-40. doi: 10.1269/jrr.10097.
African green monkey kidney cells, CV-1, were irradiated with Carbon ions (LET: 735 keV/µm Argon ions (LET: 3,000 keV/µm) to visualize ion tracks through the cell nucleus by labeling the 3'-OH termini result of DNA strand breaks. The 3'-OH termini of DNA were labeled with BrdU-triphosphate catalyzed by TdT. This method of TUNEL (TdT-mediated dUTP Nick End labeling) is based on the specific binding of TdT to 3'-OH termini of DNA. Subsequent immuno-fluorescent staining with the primary monoclonal antibody against BrdU, followed by a secondary antibody of Alexa Fluor 488, was performed to visualize the BrdU labeled DNA termini. Images of the cell nuclei were acquired by confocal laser microscopy. When cell monolayers were irradiated perpendicularly with argon ions, induced DSBs in cell nuclei were identifiable as fluorescent spots. In another irradiation setup, when cells were irradiated at a small angle with incident argon ions, DNA strand breaks were detected as fluorescent stripes across the cell nucleus. These results demonstrate the induction of 3'-OH termini at sites of DNA strand breaks along Argon ion tracks.
用碳离子（线性能量传递：735keV/μm）和氩离子（线性能量传递：3000keV/μm）辐照非洲绿猴肾细胞（CV-1），通过标记 DNA 链断裂的 3'-OH 末端，可视化离子在细胞核中的轨迹。TUNEL（末端转移酶介导的 dUTP 缺口末端标记）法用 TdT 催化 BrdU-三磷酸进行 3'-OH 末端的标记。这种 TdT 介导的 dUTP 缺口末端标记法基于 TdT 与 DNA 3'-OH 末端的特异性结合。然后用针对 BrdU 的单克隆抗体进行免疫荧光染色，再用 Alexa Fluor 488 标记的二抗进行染色，以可视化 BrdU 标记的 DNA 末端。通过共聚焦激光显微镜获取细胞核的图像。当细胞单层垂直辐照氩离子时，可识别细胞核中诱导的 DSB 为荧光斑点。在另一种辐照设置中，当细胞以小角度辐照时，可检测到穿过细胞核的 DNA 链断裂的荧光条纹。这些结果表明，沿着氩离子轨迹，在 DNA 链断裂部位诱导了 3'-OH 末端。
