MUTATION INDUCTION BY CYTOPLASMIC IRRADIATION IN MAMMALIAN CELLS

哺乳动物细胞中细胞质辐射诱导突变

• 批准号: 6346378
• 负责人: LJ WU
• 金额: $ 13.65万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-01 至 2001-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6346378
• 关键词: animal tissue; biomedical resource; environmental health; human tissue

The biological consequences of cytoplasmic irradiation in mammalian cells are largely unknown. Using the microbeam at the Radiological Research Accelerator Facility, we examined cell lethality, mutation induction and the functional role of reactive oxygen species in human-hamster hybrid (AL) cells traversed by an exact number of alpha particles (150 keV/(m) through their cellular cytoplasm. Dual fluorochrome dyes and an image analysis system were used to determine the irradiation positions off the long ends of each cell. In comparison to nuclear irradiation (Hei et al., PNAS. 94: 3765,1997), cytoplasmic irradiation induced minimal toxicity such that traversal of cells with 4 alpha particles resulted in a surviving fraction of ~0.9. While cytoplasmic traversal with either 1 or 2 particles induced few S1- mutants in AL cells, those irradiated with 4 or more particles had an induced mutant fraction that was 2.5 fold higher than the background incidence. The particle delivery and imaging systems are so designed such that the chance of hitting the nucleus is only 0.4% with 4 (-particle traversals. In contrast to the multilocus deletions predominately induced by nuclear traversals, S1-mutants induced by cytoplasmic irradiation involved mostly small alterations similar to those of spontaneous origin. Concurrent treatment of cells with 8% DMSO significantly reduced the mutagenic potential of cytoplasmic irradiation. In contrast, pretreatment of cells with 10 mM of buthionine S-R sulfoximine, which reduces the cellular non-protein sulfhydryl levels to less than 5% of control levels, significantly enhances the mutagenic incidence by cytoplasmic irradiation. Our results show, for the first time, that cytoplasmic traversal of mammalian cells by (-particles is mutagenic via a mechanism different from that of nuclear traversal, probably involving oxyradicals.

细胞质照射的生物学后果 哺乳动物细胞很大程度上是未知的。 使用微束 放射学研究加速器设施，我们检查了细胞 致死性、突变诱导和反应性的功能作用 人仓鼠杂种 (AL) 细胞中的氧物种 通过其细胞的α粒子的确切数量（150 keV/（m）） 细胞质。 双荧光染料和图像分析系统 用于确定每个长端的照射位置 细胞。 与核辐射相比（Hei 等人，PNAS. 94： 3765,1997)，细胞质照射引起的毒性最小，使得 用 4 个 α 粒子遍历细胞导致存活 ~0.9 的分数。 当 1 或 2 进行细胞质遍历时 粒子在 AL 细胞中诱导很少的 S1-突变体，那些用 4 或更多颗粒的诱导突变分数为 2.5 倍 高于背景发生率。 颗粒输送和 成像系统的设计使得击中目标的机会 核只有 0.4%，有 4 次 (-粒子遍历)。与 主要由核遍历诱导的多位点缺失， 细胞质照射诱导的 S1 突变体大多涉及较小的 类似于自发发生的改变。 并发 用 8% DMSO 处理细胞可显着降低致突变性 细胞质照射的潜力。 相比之下，预处理 用 10 mM 丁硫氨酸 S-R 亚砜亚胺对细胞进行处理，可降低 细胞非蛋白质巯基水平低于对照的 5% 水平，显着提高细胞质诱变发生率 辐照。 我们的结果首次表明，细胞质 (-粒子对哺乳动物细胞的遍历具有诱变性 机制与核穿越不同，可能涉及 氧自由基。