Centro de Estudios Fotosintéticos y Bioquímicos, Universidad Nacional de Rosario Rosario, Argentina.
Front Plant Sci. 2013 Oct 21;4:420. doi: 10.3389/fpls.2013.00420. eCollection 2013.
Absorption of UV-B by DNA induces the formation of covalent bonds between adjacent pyrimidines. In maize and arabidopsis, plants deficient in chromatin remodeling show increased DNA damage compared to WT plants after a UV-B treatment. However, the role of enzymes that participate in DNA methylation in DNA repair after UV-B damage was not previously investigated. In this work, we analyzed how chromatin remodeling activities that have an effect on DNA methylation affects the repair of UV-B damaged DNA using plants deficient in the expression of DDM1 and ROS1. First, we analyzed their regulation by UV-B radiation in arabidopsis plants. Then, we demonstrated that ddm1 mutants accumulated more DNA damage after UV-B exposure compared to Col0 plants. Surprisingly, ros1 mutants show less CPDs and 6-4PPs than WT plants after the treatment under light conditions, while the repair under dark conditions is impaired. Transcripts for two photolyases are highly induced by UV-B in ros1 mutants, suggesting that the lower accumulation of photoproducts by UV-B is due to increased photorepair in these mutants. Finally, we demonstrate that oxidative DNA damage does not occur after UV-B exposure in arabidopsis plants; however, ros1 plants accumulate high levels of oxoproducts, while ddm1 mutants have less oxoproducts than Col0 plants, suggesting that both ROS1 and DDM1 have a role in the repair of oxidative DNA damage. Together, our data provide evidence that both DDM1 and ROS1, directly or indirectly, participate in UV-B induced- and oxidative DNA damage repair.
UV-B 被 DNA 吸收会导致相邻嘧啶之间形成共价键。在玉米和拟南芥中，与 WT 植物相比，缺乏染色质重塑的植物在 UV-B 处理后显示出更多的 DNA 损伤。然而，以前没有研究过参与 DNA 甲基化的酶在 UV-B 损伤后 DNA 修复中的作用。在这项工作中，我们使用表达 DDM1 和 ROS1 缺陷的植物分析了对 DNA 甲基化有影响的染色质重塑活性如何影响 UV-B 损伤 DNA 的修复。首先，我们分析了它们在拟南芥植物中对 UV-B 辐射的调节。然后，我们证明与 Col0 植物相比，ddm1 突变体在暴露于 UV-B 后积累了更多的 DNA 损伤。令人惊讶的是，ros1 突变体在光照条件下比 WT 植物积累的 CPDs 和 6-4PPs 更少，而在黑暗条件下的修复受损。在 ros1 突变体中，两种光解酶的转录物被 UV-B 高度诱导，表明这些突变体中增加的光修复导致 UV-B 下光产物的积累减少。最后，我们证明在 UV-B 暴露后，拟南芥植物中不会发生氧化 DNA 损伤；然而，ros1 植物积累了高水平的氧化产物，而 ddm1 突变体比 Col0 植物积累的氧化产物更少，这表明 ROS1 和 DDM1 都参与了氧化 DNA 损伤的修复。总之，我们的数据提供了证据表明，DDM1 和 ROS1 直接或间接地参与了 UV-B 诱导的和氧化的 DNA 损伤修复。
