Functional analyses of NPR1 in plant defense

先天免疫机制在进化中是保守的。拟南芥的NPR 1蛋白是一种 植物防御中基因表达的主要调节因子。类似于哺乳动物的免疫- 调节因子NF-kB，NPR 1蛋白在诱导时发生核转位。在静止状态下， NPR 1作为与细胞器翻译延伸因子的复合物存在于细胞质中 EF-Tu通过二硫键。病原体攻击后水杨酸的增加导致 双相氧化还原变化和NPR 1单体释放进入细胞核。NPR 1 蛋白质水平通过细胞核中蛋白酶体介导的降解而波动。这种动态 NPR 1的功能需要这种改变，并且这种改变通过DSXXXS（“IkB”）的磷酸化来促进 站点”）在NPR 1中找到。NPR 1作为TGA转录的辅因子控制基因表达 因素基因组和遗传学研究鉴定了HSF 4和几种DNA 损伤修复蛋白，如BRCA 2A和RAD 51 D，作为参与 NPR 1介导的基因表达。在目标1中，我们将揭示 NPR 1-EF-Tu复合物存在于细胞质中。NPR 1-EF-Tu相互作用将被破坏 通过诱变以确定EF-Tu是否仅是NPR 1寡聚体的一部分或还连接 防御与细胞器活动。由于EF-Tu是已知的植物防御诱导子，我们还将 研究假单胞菌EF-Tu干扰NPR 1寡聚体形成的可能性 在感染期间。在目的2中，我们将研究NPR 1单体的振荡。IkB位点突变体 将进一步研究以了解磷酸化在NPR 1功能中的调节作用。 将鉴定相应的蛋白激酶。在目标3中，我们将分离和表征 使用TAP标记的NPR 1的NPR 1核复合物。NPR1， 转录因子和染色质重塑蛋白将被检查和表征， 暂时的时尚该项目对人类健康的意义有两个方面：第一， 了解防御和细胞器活动之间的相互作用， 转录调控，以及防御相关转录和DNA之间的可能联系 重组是与所有真核生物相关的高度新颖的研究领域。第二、 环境健康直接影响人类健康。利用植物先天免疫 控制疾病将有助于减少农药污染，增加食物营养， 和人力资源。该项目对人类健康的意义有两个方面：一是研究相声 细胞质/核功能和细胞器活性之间的关系，了解 转录调控周期性的生物学意义，并建立一个链接 病原体诱导的基因表达和DNA修复机制之间的联系可能导致 基础生物学中激动人心的新发现第二，人类健康直接受到 环境卫生。利用植物天然免疫来控制作物中的疾病， 有助于减少农药污染，增加食品营养，节约自然和人类 资源

Innate immune mechanisms are conserved in evolution. The NPR1 protein of Arabidopsis is a master regulator of gene expression in plant defense. Similar to the mammalian immuno- regulator NF-kB, the NPR1 protein is nuclear translocated upon induction. In the resting state, NPR1 is present in the cytoplasm as a complex with the organelle translation elongation factor EF-Tu through disulfide bonds. An increase in salicylic acid upon pathogen challenge results in a biphasic redox change and the release of NPR1 monomer to enter the nucleus. The NPR1 protein levels oscillate through proteasome-mediated degradation in the nucleus. This dynamic change is required for NPR1 function and is facilitated by phosphorylation of DSXXXS ("IkB site") found in NPR1. NPR1 controls gene expression as a cofactor for the TGA transcription factors. Genomic and genetic studies led to the identification of HSF4 and several DNA damage repair proteins such as BRCA2A and RAD51D as additional nuclear factors involved in NPR1-mediated gene expression. In aim 1, we will reveal the biological significance of the NPR1-EF-Tu complex found in the cytoplasm. The NPR1-EF-Tu interaction will be disrupted through mutagenesis to determine whether EF-Tu is only part of the NPR1 oligomer or also links defense with organelle activities. Since EF-Tu is a known elicitor of plant defense, we will also investingate the possibility that Pseudomonas EF-Tu interferes with NPR1 oligomer formation during infection. In aim 2, we will study the oscillation of NPR1 monomer. The IkB site mutants will be further studied to understand the regulatory role of phosphorylation in NPR1 function. The corresponding protein kinase will be identified. In aim 3, we will isolate and characterize the NPR1 nuclear complex using TAP-tagged NPR1. Physical interactions between NPR1, transcription factors and chromatin remodeling proteins will be examined and characterized in a temporal fashion. The significance of the project to human health is two-fold: First, understanding the interplay between defense and organelle activity, the oscillation in transcription regulation, and a possible link between defense-associated transcription and DNA recombination are highly novel research areas relevant to all eukaryotic organisms. Second, human health is directly impacted by environmental health. Using plant innate immunity to control diseases will help reduce pesticide pollution, increase food nutrition, and save natural and human resources. The significance of the project to human health is two-fold: First, studying the crosstalk between cytoplasmic/nuclear function and organelle activity, understanding the biological significance of periodicity in transcription regulation, and establishing a link between pathogen-induced gene expression and DNA repair machinery may lead to exciting new discoveries in basic biology. Second, human health is directly impacted by environmental health. Using plant innate immunity to control disease in crop plants will help reduce pesticide pollution, increase food nutrition, and save natural and human resources.