Modulation of RNA processing by abscisic acid

植物激素脱落酸(ABA)调节植物的各种发育和胁迫诱导过程。一些ABA反应基因编码RNA结合蛋白或RNA加工蛋白，最近对拟南芥ABA敏感突变体的研究表明，ABA参与转录后mRNA的加工。拟南芥基因组编码200多种假定的RNA结合蛋白，其中一半是植物特有的。RNA结合蛋白介导了mRNA的合成、剪接、运输、翻译和降解，并通过影响转录本的丰度，在微调细胞蛋白质表达方面发挥了重要的调节作用。我们对植物RNA结合蛋白的了解非常有限，只有少数几种植物RNA结合蛋白被鉴定，对它们的作用机制知之甚少。大多数植物中的RNA结合蛋白都与ABA直接或间接相关。我已经鉴定出RNA结合蛋白FCA是植物中第一个ABA受体，并提供了第一个植物激素与RNA加工的直接联系。通过这个研究计划，我试图了解ABA调节植物细胞RNA加工的机制。本研究的目的是研究ABA可能参与调节RNA的加工，确定RNA结合的特异性，以及RNA结合蛋白的相互作用。这项研究将包括体内和体外研究，利用两种ABA受体蛋白，拟南芥FCA及其谷类同源物ABAP1。我的研究计划将有助于现有的关于基因表达调控机制的知识，并将是第一个研究植物RNA新陈代谢的激素调控的项目。我的研究成果将对植物生长发育的基本过程产生直接而深远的影响，并可用于筛选具有高产潜力和对生物和非生物胁迫具有高度耐受性的农业重要作物。

The phytohormone abscisic acid (ABA) regulates various developmental and stress-induced processes in plants. Several ABA response genes encode for RNA-binding or RNA-processing proteins, and recent studies on Arabidopsis ABA-sensitivity mutants have shown ABA involvement in post-transcriptional mRNA processing. Arabidopsis genome encodes more than 200 putative RNA-binding proteins; half of which are plant-specific. RNA-binding proteins mediate mRNA synthesis, splicing, transport, translation and degradation and by influencing transcript abundance, RNA-binding proteins provide a major regulatory role in fine-tuning cellular protein expression.Our knowledge of plant RNA-binding proteins is very limited and only a few plant RNA-binding proteins are characterized, with little or no information available on the mechanism by which their action is regulated. Most of the studied RNA-binding proteins in plants are directly or indirectly linked to ABA.I have identified the RNA binding protein, Flowering Time Control Locus A (FCA), as the first ABA receptor in plants and provided the first direct link of a plant hormone to RNA processing.Through this research program, I seek to understand the mechanisms by which ABA regulates RNA processing in plant cells. The objectives of this research are to investigate possible involvement of ABA in regulating RNA processing, determining of RNA binding specificity, and in the interactions of the RNA-binding proteins. This research will comprise both in vivo and in vitro studies, utilizing two ABA receptor proteins, the Arabidopsis FCA and its cereal homologue, ABAP1. My research program will contribute to the existing knowledge on the mechanisms that regulate gene expression and will be the first to look at hormonal regulation of RNA metabolism in plants. My research progrm will have immediate and far-reaching impacts on the fundamental processes of plant growth and development, and can be applied to select for agriculturally important crops that possess high-yield potential and exert high tolerance to biotic and abiotic stresses.