NOR1参与抑制植物转录后基因沉默的分子机理研究

由AGO1等蛋白介导的转录后基因沉默是依赖于小RNA的mRNA沉默过程，该过程在调控植物生长发育及抵御病毒侵染过程中发挥着极其重要的作用。有研究表明植物体内异常mRNA过度积累可以触发转录后基因沉默的活化，从而对相应的mRNA进行降解。而RNA质量控制系统是一种植物内源的依赖于SKI复合体及XRN复合体的对异常mRNA进行监控和清理的途径；SKI复合体负责mRNA的3’端降解，XRN复合体负责5’端降解。RNA质量控制系统可以抑制转录后基因沉默，防止植物内源基因被错误沉默。除了上述已经报道的RNA质量控制系统外，其它的转录后基因沉默抑制因子还鲜有报道。在本项目中的工作中，申请人的前期的工作鉴定到一个全新的蛋白（NOR1），该蛋白很有可能不依赖于RNA质量控制系统对转录后基因沉默途径进行抑制。在本项目中，申请人将结合多种生物学方法对NOR1抑制转录后基因沉默的分子机制进行解析。

Small RNA dependent post-transcriptional gene silencing mediating by AGO1 and other proteins is the most important way to degrade mRNA, it plays crucial roles in modulating plant development and defensing virus infecting. Previous studies have shown that excessive accumulation of abnormal mRNA in plants can trigger the activation of post-transcriptional gene silencing, thereby degrading the corresponding mRNA. The RNA quality control system is an endogenous way of monitoring and cleaning up abnormal mRNA depending on SKI complex and XRN complex; the SKI complex is responsible for the degradation of mRNA from the 3’ end, while the XRN complex is responsible for the degradation from the 5' end. RNA quality control systems can suppress post-transcriptional gene silencing and prevent plant endogenous genes from being inappropriate silenced. In addition to RNA quality control systems, other post-transcriptional gene silencing suppressors have rarely been reported. In this project, our previous work identified a novel protein (NOR1) that is likely to repress the post-transcriptional gene silencing pathway independent of RNA quality control systems. In this project, we will study the molecular mechanism of NOR1 suppressing post-transcriptional gene silencing using a variety of biological methods.