The Arabidopsis SIAMESE-RELATED Cyclin-Dependent Kinase Inhibitors SMR5 and SMR7 Regulate the DNA Damage Checkpoint in Response to Reactive Oxygen Species
The Arabidopsis SIAMESE-RELATED Cyclin-Dependent Kinase Inhibitors SMR5 and SMR7 Regulate the DNA Damage Checkpoint in Response to Reactive Oxygen Species
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DOI：
10.1105/tpc.113.118943
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发表时间：
2014-01-01
期刊：
影响因子：
11.6
通讯作者：
De Veylder, Lieven
中科院分区：
文献类型：
--
作者：
Yi, Dalong;Kamei, Claire Lessa Alvim;De Veylder, Lieven
尽管我们对基因组损伤后帮助DNA修复的多种途径的了解正在稳步增加，但对调节植物细胞周期以响应DNA胁迫的分子参与者知之甚少。通过对DNA应激微阵列数据集的荟萃分析，发现SIAMESE/SIAMESE相关（SIM/SMR）类细胞周期蛋白依赖性激酶抑制剂的三个家族成员对遗传毒性反应强烈。转录报告构建证实了特异性和强激活的三个SIM/SMR基因的分生组织DNA应力后，而过表达分析证实了它们的细胞周期抑制潜力。与检查点调节剂一致，SMR 5和SMR 7敲除植物在用复制抑制药物羟基脲（HU）处理后在叶细胞中显示受损的检查点。令人惊讶的是，HU-induced SMR 5/SMR 7的表达依赖于共济失调性毛细血管扩张突变（ATM）和γ反应的供应1，而不是预期的复制应激激活ATM和RAD 3相关激酶。这种明显的差异是通过证明，除了其对复制的影响，HU触发活性氧（ROS）的形成来解释的。通过不同的ROS诱导条件，包括高光处理，证实了SMR基因的ROS依赖性转录激活。我们的结论是，所确定的SMR基因是一个信号级联的一部分，诱导细胞周期检查点响应ROS诱导的DNA损伤。
Whereas our knowledge about the diverse pathways aiding DNA repair upon genome damage is steadily increasing, little is known about the molecular players that adjust the plant cell cycle in response to DNA stress. By a meta-analysis of DNA stress microarray data sets, three family members of the SIAMESE/SIAMESE-RELATED (SIM/SMR) class of cyclin-dependent kinase inhibitors were discovered that react strongly to genotoxicity. Transcriptional reporter constructs corroborated specific and strong activation of the three SIM/SMR genes in the meristems upon DNA stress, whereas overexpression analysis confirmed their cell cycle inhibitory potential. In agreement with being checkpoint regulators, SMR5 and SMR7 knockout plants displayed an impaired checkpoint in leaf cells upon treatment with the replication inhibitory drug hydroxyurea (HU). Surprisingly, HU-induced SMR5/SMR7 expression depends on ATAXIA TELANGIECTASIA MUTATED (ATM) and SUPPRESSOR OF GAMMA RESPONSE1, rather than on the anticipated replication stress-activated ATM AND RAD3-RELATED kinase. This apparent discrepancy was explained by demonstrating that, in addition to its effect on replication, HU triggers the formation of reactive oxygen species (ROS). ROS-dependent transcriptional activation of the SMR genes was confirmed by different ROS-inducing conditions, including high-light treatment. We conclude that the identified SMR genes are part of a signaling cascade that induces a cell cycle checkpoint in response to ROS-induced DNA damage.