Role of microtubules in the non-cell autonomous activities of plant microRNAs

项目摘要 microRNA（miRNAs）是基因表达的序列特异性调节因子，其影响几乎所有生物学过程。 在不同的真核生物中。基于miRNA调控的缺陷导致发育和生理 植物和动物的异常。经过近20年的研究， 负责miRNA生物发生和作用模式的基因已经被发现。然而，由于大多数生物化学 使用无细胞提取物进行了对miRNA或相关小干扰RNA的研究，了解小干扰RNA如何 RNA机器与细胞骨架的相互作用在很大程度上仍然是未知的。从历史上看，miRNAs被视为 细胞自主调节分子，但近年来，越来越多的证据表明， 动物细胞外囊泡中的miRNAs以及植物细胞间miRNAs的运动。 尽管越来越多的证据表明miRNAs是细胞间通讯的信息分子， miRNAs具有生物学意义的非细胞自主活性的范围在很大程度上是未知的，更不用说 启动、限制或调节miRNA的非细胞自主性的分子机制。 该项目探讨了miRNAs作为细胞间信息分子的作用范围， 通信和调查的非细胞自主活动的miRNAs的机制 使用拟南芥模型。除了作为可用资源的复杂工具集之外， 包括一些miRNAs的非细胞自主活动， 完整的植物和易于进行正向遗传筛选，不需要任何先验假设 关于miRNA的非细胞自主性的细胞机制。私家侦探小组的基因筛查 揭示了微管与非细胞自主活动之间的一种先前未被怀疑的联系， miRNAs以及miRNAs的翻译抑制活性与它们之间的诱人联系， 非细胞自主活动。该项目利用了根中的分层细胞组织， 采用单细胞层分辨率的基因组学方法来研究微管如何使非细胞 miRNAs的自主活动。 通过阐明miRNA的非细胞自主性的范围，该项目有可能改变 认为miRNAs在很大程度上是细胞自主作用的教条，并设定了miRNAs作为细胞信号的范式， 手机通讯通过开拓性的努力来询问非细胞的潜在机制， miRNAs的自主活动，该项目将提供在这个基本上未知的领域的初步知识， 为今后的学习打下基础。通过揭示细胞骨架在小RNA生物学中的作用， 这个项目的范围将超越植物生物学。

PROJECT SUMMARY microRNAs (miRNAs) are sequence-specific regulators of gene expression that impact almost all biological processes in diverse eukaryotes. Defects in miRNA-based regulation lead to developmental and physiological abnormalities in both plants and animals. Thanks to nearly two decades of research, the molecular machinery responsible for miRNA biogenesis and modes of action has been uncovered. However, since most biochemical studies on miRNAs or related small interfering RNAs were performed with cell-free extracts, how the small RNA machinery interplays with the cytoskeleton remains largely unknown. Historically, miRNAs are viewed as cell-autonomous regulatory molecules, but in recent years, mounting evidence points to the existence of miRNAs in extracellular vesicles in animals as well as the movement of miRNAs between cells in plants. Despite accumulating evidence implicating miRNAs as informational molecules in cell-cell communications, the scope of biologically significant, non-cell autonomous activities of miRNAs is largely unknown, let alone the molecular mechanisms that enable, constrain, or regulate the non-cell autonomy of miRNAs. The project interrogates the scope of miRNAs serving as informational molecules in cell-cell communications and investigates the mechanisms underlying the non-cell autonomous activities of miRNAs using the Arabidopsis model. In addition to sophisticated tool sets as available resources, advantages offered by the Arabidopsis model include the well-documented, non-cell autonomous activities of a few miRNAs in intact plants and the ease to perform forward genetic screens that do not require any a priori assumptions regarding the cellular machinery for miRNA’s non-cell autonomy. A forward genetic screen from the PI’s group revealed a previously unsuspected link between microtubules and the non-cell autonomous activities of miRNAs as well as a tantalizing connection between the translation repression activities of miRNAs and their non-cell autonomous activities. The project takes advantage of the layered cell organization in roots and employs genomics approaches at single-cell-layer resolution to study how microtubules enable the non-cell autonomous activities of miRNAs. By elucidating the scope of miRNA’s non-cell autonomy, the project has the potential to change the dogma that miRNAs largely act cell-autonomously and set the paradigm that miRNAs serve as signals in cell- cell communications. Through pioneering efforts to interrogate mechanisms underlying the non-cell autonomous activities of miRNAs, the project will provide initial knowledge in this largely unknown territory and set the foundation for future studies. By revealing a role of the cytoskeleton in small RNA biology, the impacts of the project will reach beyond plant biology.