Yoshiyama Kaoru O, Kimura Seisuke, Maki Hisaji, Britt Anne B, Umeda Masaaki
Department of Bioresource and Environmental Sciences; Kyoto Sangyo University; Kamigamo-Motoyama; Kitaku, Kyoto, Japan.
Graduate School of Biological Sciences; Nara Institute of Science and Technology; Takayama; Ikoma, Nara, Japan.
Plant Signal Behav. 2014;9(4):e28889. doi: 10.4161/psb.28889.
Plants are inescapably exposed to environmental stress because of their sessile lifestyle. Such stress induces the production of reactive oxygen species (ROS), which are in turn a source of genotoxic stress. ROS are also generated intrinsically during photosynthesis in the chloroplasts. Furthermore, plants are affected by the UV component of sunlight, which damages their genomes. To protect their genomic integrity from DNA damage, plants activate a DNA damage response (DDR) system that regulates cell cycle arrest, DNA repair, and programmed cell death. Although plants have orthologs of several of the DDR factors that are found in animals, certain critical animal DDR factors, notably the tumor suppressor p53 and the DDR kinases CHK1 and CHK2, have not been found in plants. In this mini-review, we summarize the functions and regulatory mechanism of Arabidopsis thaliana SUPPRESSOR OF GAMMA RESPONSE 1 (SOG1), a plant-specific transcription factor that plays a central role in the DDR. The characteristics of SOG1 are similar to those of animal p53, even though the proteins' amino acid sequences are unrelated. We suggest that plants acquired the central transcriptional factor SOG1 as a functional homolog of p53 during the evolution of their DDR system.
由于植物固着的生活方式，它们不可避免地会受到环境压力的影响。这种压力会诱导活性氧（ROS）的产生，而ROS反过来又是遗传毒性压力的一个来源。ROS也在叶绿体光合作用过程中内在地产生。此外，植物还受到阳光中紫外线成分的影响，紫外线会损害它们的基因组。为了保护其基因组完整性免受DNA损伤，植物激活了一个DNA损伤反应（DDR）系统，该系统调节细胞周期停滞、DNA修复和程序性细胞死亡。尽管植物具有一些在动物中发现的DDR因子的直系同源物，但某些关键的动物DDR因子，特别是肿瘤抑制因子p53以及DDR激酶CHK1和CHK2，在植物中尚未被发现。在这篇小型综述中，我们总结了拟南芥γ反应抑制因子1（SOG1）的功能和调控机制，SOG1是一种在DDR中起核心作用的植物特异性转录因子。尽管SOG1和动物p53的蛋白质氨基酸序列不相关，但SOG1的特性与动物p53相似。我们认为，在植物DDR系统的进化过程中，植物获得了中心转录因子SOG1作为p53的功能同源物。
