Hirakawa Takeshi, Katagiri Yohei, Ando Tadashi, Matsunaga Sachihiro
Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan.
Laboratory for Biomolecular Function Simulation, Computational Biology Research Core, RIKEN Quantitative Biology Center, International Medical Device Alliance, 1-6-5 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0074, Japan.
Sci Rep. 2015 Jun 5;5:11058. doi: 10.1038/srep11058.
Chromatin dynamics and arrangement are involved in many biological processes in nuclei of eukaryotes including plants. Plants have to respond rapidly to various environmental stimuli to achieve growth and development because they cannot move. It is assumed that the alteration of chromatin dynamics and arrangement support the response to these stimuli; however, there is little information in plants. In this study, we investigated the chromatin dynamics and arrangement with DNA damage in Arabidopsis thaliana by live-cell imaging with the lacO/LacI-EGFP system and simulation analysis. It was revealed that homologous loci kept a constant distance in nuclei of A. thaliana roots in general growth. We also found that DNA double-strand breaks (DSBs) induce the approach of the homologous loci with γ-irradiation. Furthermore, AtRAD54, which performs an important role in the homologous recombination repair pathway, was involved in the pairing of homologous loci with γ-irradiation. These results suggest that homologous loci approach each other to repair DSBs, and AtRAD54 mediates these phenomena.
染色质动力学和排列参与包括植物在内的真核生物细胞核中的许多生物学过程。由于植物不能移动，它们必须快速响应各种环境刺激以实现生长和发育。据推测，染色质动力学和排列的改变有助于对这些刺激作出反应；然而，在植物中相关信息很少。在本研究中，我们通过使用lacO/LacI-EGFP系统的活细胞成像和模拟分析，研究了拟南芥中DNA损伤时的染色质动力学和排列。结果表明，在正常生长的拟南芥根细胞核中，同源位点保持恒定距离。我们还发现，DNA双链断裂（DSB）会通过γ射线诱导同源位点靠近。此外，在同源重组修复途径中起重要作用的AtRAD54参与了γ射线照射下同源位点的配对。这些结果表明，同源位点相互靠近以修复DSB，并且AtRAD54介导了这些现象。
