Modification and dynamic regulation of Argonaute proteins-the key small RNA pathway components in host innate immunity

 描述(申请人提供)：真核生物，包括动物和植物，已经进化出复杂的免疫系统来保护自己免受病原体的侵袭。小RNA(SRNAs)是一种短的、非编码的调节性RNA，通过与ArgAerte(AGO)蛋白结合并指导具有互补序列的基因的沉默来诱导RNA干扰(RNAi)。我们和其他人的工作已经证明，来自宿主或病原体的sRNA通过AGO蛋白发挥作用，并在宿主与病原体的相互作用中发挥重要作用。然而，潜在的监管机制仍然难以捉摸。我们的长期目标是了解sRNAs和RNAi在宿主先天免疫中的动态调节。AGO蛋白是SRNA介导的基因沉默的关键角色，我们假设它们被相关蛋白修饰和调节，以调节SRNA介导的基因沉默。在这里，我们试图了解agos在RNAi途径中的修饰和调控，以及在寄主的抗菌和抗真菌免疫反应中，通过模拟植物-病原菌相互作用系统-拟南芥及其细菌病原菌紫丁香假单胞菌和侵袭性真菌病原菌Botrytis cinerea。在过去的资助期间，我们已经鉴定了不同类别的调节宿主免疫的寄主sRNAs，并证明了拟南芥AGO2(AtAGO2)是由细菌感染高度诱导并正向调节宿主免疫的。我们还表明，灰霉菌将其sRNA运送到宿主细胞中，并劫持宿主AtAGO1，以抑制宿主免疫基因，从而成功感染。为了从机制上了解AtAGO1和AtAGO2是如何调控的，我们通过蛋白质组学分析鉴定了它们的相关蛋白质。这次更新将研究在RNAi途径和宿主先天免疫中AtAGO1和AtAGO2的相关蛋白对其的修饰和调节。这项研究的成果将极大地促进我们对RNAi在宿主对病原体的免疫反应中的动态调控的理解，这将对农业和人类健康产生重大影响。其具体目的是：1.阐明蛋白精氨酸甲基转移酶在修饰和调节ATAGO功能中对宿主免疫的作用。2.研究类DDX3 RNA解旋酶在宿主免疫中调节ATAGO功能的作用。3.研究蛋白磷酸酶对ATAGO和宿主免疫的调节作用。

 DESCRIPTION (provided by applicant): Eukaryotic organisms, including animals and plants, have evolved sophisticated immune systems to protect themselves against pathogens. Small RNAs (sRNAs) are short, non-coding regulatory RNAs that induce RNA interference (RNAi) by binding to Argonaute (AGO) proteins and directing silencing of genes with complementary sequences. Our work and those of others have demonstrated that sRNAs, derived from either hosts or pathogens, function through AGO proteins and play an important role in host-pathogen interactions. However, the underlying regulatory mechanisms remain elusive. Our long-term goal is to understand the dynamic regulation of sRNAs and RNAi in host innate immunity. AGO proteins are key players of sRNA- mediated gene silencing, and we hypothesize that they are modified and regulated by their associated proteins to modulate sRNA-mediated gene silencing. Here, we seek to understand the modification and regulation of AGOs in RNAi pathway, and in host antibacterial and antifungal immune responses, by using model plant-pathogen interaction systems - Arabidopsis thaliana and its bacterial pathogen Pseudomonas syringae and aggressive fungal pathogen Botrytis cinerea. During the last funding period, we have identified diverse classes of host sRNAs regulating host immunity, and have demonstrated that Arabidopsis AGO2 (AtAGO2) is highly induced by bacterial infection and positively regulates host immunity. We have also shown that B. cinerea delivers its sRNAs into host cells and hijacks host AtAGO1 to suppress host immunity genes for successful infection. To obtain a mechanistic understanding of how AtAGO1 and AtAGO2 are regulated, we have identified their associated proteins via proteomics analysis. This renewal will study the modification and regulation of AtAGO1 and AtAGO2 by their associated proteins in RNAi pathways and host innate immunity. The output of this study will significantly advance our understanding of dynamic control of RNAi in host immune responses against pathogens, which will have great impact on both agricultural and human health. The specific aims are: 1. Elucidate the role of protein arginine methyltransferases in modification and regulation of AtAGO function in host immunity. 2. Investigate the function of DDX3-like RNA helicases in modulating AtAGO function in host immunity. 3. Study the role of protein phosphatases in modulating AtAGO and host immunity.