Light signaling controls nuclear architecture reorganization during seedling establishment
Light signaling controls nuclear architecture reorganization during seedling establishment
复制标题
DOI：
10.1073/pnas.1503512112
复制
发表时间：
2015-05-26
影响因子：
11.1
通讯作者：
Barneche, Fredy
中科院分区：
文献类型：
--
作者：
Bourbousse, Clara;Mestiri, Imen;Barneche, Fredy
在植物体细胞中，染色质的空间组织可以受到广泛的重塑，以响应发育和环境信号。然而，控制这些动态变化的机制及其对核活动的功能影响知之甚少。在这里，我们确定，光感知触发两个不同的核架构之间的开关在拟南芥胚后发育。虽然子叶细胞中的渐进核扩张和异染色质重排在萌发过程中在光照和黑暗条件下同样实现，但导致成熟核表型的后期步骤与器官特异性方式的光形态发生转变密切相关。光信号整合子DE-ETIOLATED 1和CONSTITIVE PHOMOPHOGENIC 1使黄化子叶中的异染色质保持解致密状态。相比之下，在光照条件下，隐花色素介导的光感知会在明显的色中心内释放核膨胀和异染色质致密化。对于所有测试的基因座，染色质凝聚在光形态建成不依赖于DNA甲基化为基础的过程检测。尽管如此，转录基因沉默的效率可能会受到影响，在过渡期间，基于转座元件驱动的报告基因的重新激活。最后，我们报告说，全球参与的RNA聚合酶II在转录的高度增加，在光照条件下，这表明子叶光形态建成涉及从全球静止到更活跃的转录状态的过渡。鉴于这些发现，我们提出，光引发的核结构的变化是异染色质重组和转录重编程与光合作用的建立之间的相互作用的基础。
The spatial organization of chromatin can be subject to extensive remodeling in plant somatic cells in response to developmental and environmental signals. However, the mechanisms controlling these dynamic changes and their functional impact on nuclear activity are poorly understood. Here, we determined that light perception triggers a switch between two different nuclear architectural schemes during Arabidopsis postembryonic development. Whereas progressive nucleus expansion and heterochromatin rearrangements in cotyledon cells are achieved similarly under light and dark conditions during germination, the later steps that lead to mature nuclear phenotypes are intimately associated with the photomorphogenic transition in an organ-specific manner. The light signaling integrators DE-ETIOLATED 1 and CONSTITUTIVE PHOTOMORPHOGENIC 1 maintain heterochromatin in a decondensed state in etiolated cotyledons. In contrast, under light conditions cryptochrome-mediated photoperception releases nuclear expansion and heterochromatin compaction within conspicuous chromocenters. For all tested loci, chromatin condensation during photomorphogenesis does not detectably rely on DNA methylation-based processes. Notwithstanding, the efficiency of transcriptional gene silencing may be impacted during the transition, as based on the reactivation of transposable element-driven reporter genes. Finally, we report that global engagement of RNA polymerase II in transcription is highly increased under light conditions, suggesting that cotyledon photomorphogenesis involves a transition from globally quiescent to more active transcriptional states. Given these findings, we propose that light-triggered changes in nuclear architecture underlie interplays between heterochromatin reorganization and transcriptional reprogramming associated with the establishment of photosynthesis.