Department of Plant Biology, University of California at Davis Davis, CA, USA ; Graduate Program in Genetics, University of California at Davis Davis, CA, USA.
Department of Plant Biology, University of California at Davis Davis, CA, USA.
Front Plant Sci. 2014 May 20;5:206. doi: 10.3389/fpls.2014.00206. eCollection 2014.
Low linear energy transfer (LET) gamma rays and high LET HZE (high atomic weight, high energy) particles act as powerful mutagens in both plants and animals. DNA damage generated by HZE particles is more densely clustered than that generated by gamma rays. To understand the genetic requirements for resistance to high versus low LET radiation, a series of Arabidopsis thaliana mutants were exposed to either 1GeV Fe nuclei or gamma radiation. A comparison of effects on the germination and subsequent growth of seedlings led us to conclude that the relative biological effectiveness (RBE) of the two types of radiation (HZE versus gamma) are roughly 3:1. Similarly, in wild-type lines, loss of somatic heterozygosity was induced at an RBE of about a 2:1 (HZE versus gamma). Checkpoint and repair defects, as expected, enhanced sensitivity to both agents. The "replication fork" checkpoint, governed by ATR, played a slightly more important role in resistance to HZE-induced mutagenesis than in resistance to gamma induced mutagenesis.
低线性能量转移（LET）γ射线和高 LET HZE（高原子重量、高能）粒子在植物和动物中都充当强大的诱变剂。HZE 粒子产生的 DNA 损伤比γ射线产生的更为密集。为了了解对高 LET 和低 LET 辐射的抗性的遗传要求，一系列拟南芥突变体被暴露于 1GeVFe 核或γ辐射下。对种子发芽和随后幼苗生长的影响进行比较，使我们得出结论，两种类型的辐射（HZE 与γ射线）的相对生物效应（RBE）大致为 3:1。类似地，在野生型系中，体细胞杂合性丧失以大约 2:1（HZE 与γ射线）的 RBE 诱导。如预期的那样，检查点和修复缺陷增强了对两种试剂的敏感性。由 ATR 控制的“复制叉”检查点在抵抗 HZE 诱导的诱变方面比抵抗γ诱导的诱变更为重要。
