Molecular functions of nuclear pore complex proteins in plant defense signal transduction and gene expression

核膜作为基因组的保护室边界，为真核细胞控制信号事件和基因表达的特异性和时序提供了重要手段。核孔复合体由核孔蛋白(NUP)组成，穿透核膜，是调节植物细胞对病原体侵袭反应的战略平台。然而，单个核孔蛋白在植物免疫中调节核质信号传递和基因表达输出的详细分子机制和功能作用还远远不够全面。我们实验室最近的工作表明，拟南芥核孔蛋白NUP88、NUP96和NUP160通过不同的分子机制影响植物的免疫反应。NUP96和NUP160都参与了核mRNA的输出，对某些防御基因的充分表达是必不可少的。相反，NUP88选择性地减弱重要防御调节蛋白的核出口，以促进它们在核质内的积累。因此，我提出两个分项目。其中一个项目将侧重于NUP88在植物免疫中的功能作用。我们将检验这一假设，即NUP88通过调节未知免疫调节蛋白的核浓度来选择性地调节多个不同的防御信号通路。它们的鉴定和随后在植物防御信号转导中的详细功能鉴定是本项目的主要目标。另一个项目将研究NUP96和NUP160如何机械地影响特定免疫反应基因的表达和信使核糖核酸输出。我们将研究这两种核孔蛋白控制哪些信使核糖核酸的输出途径，并解决在防御基因表达调控中不依赖运输但与染色质相关的功能。这可能会为未来可持续的粮食安全揭示新的靶点和分子机制来调节植物的抗病能力。

The nuclear envelope acts as a protective compartment boundary for the genome and provides eukaryotic cells with an important means to control the specificity and timing of signaling events and gene expression. Nuclear pore complexes, composed of nucleoporin proteins (NUPs), perforate the nuclear envelope and have emerged as a strategic platform for regulating plant cellular responses to microbial pathogen attack. However, the detailed molecular mechanisms and the functional role of individual nucleoporins in regulating nucleocytoplasmic signal relay and gene expression outputs in plant immunity are far from comprehensive. Recent work in our laboratory shows that the Arabidopsis nucleoporins NUP88, NUP96 and NUP160 affect plant immune responses by different molecular mechanisms. Both NUP96 and NUP160 are involved in nuclear mRNA export and essential for full expression of certain defense genes. In contrast, NUP88 selectively attenuates nuclear export of important defense regulatory proteins to promote their accumulation inside the nucleoplasm. I therefore propose two subprojects. One project will focus on the functional role of NUP88 in plant immunity. We will test the hypothesis that NUP88 selectively modulates multiple distinct defense signaling pathways by regulating nuclear concentrations of unknown immune regulatory proteins. Their identification and subsequent detailed functional characterization in plant defense signal transduction is a major goal of this project. The other project will address how NUP96 and NUP160 mechanistically influence the expression and mRNA export of specific immune response genes. We will investigate which mRNA export pathways are controlled by these two nucleoporins and address transport-independent but chromatin-related functions in the regulation of defense gene expression. This may reveal new targets and molecular mechanisms to modulate plant disease resistance for future sustainable food security.