The Role of the dsRNA-binding HYL1 Protein in Hormone Signaling

最近发现，被称为微RNA(MiRNA)的微小RNA分子对植物和动物的发育都很重要，但人们对这种新发现的调节机制是如何运作的知之甚少。首席研究员的实验室已经在具有良好特性的实验植物拟南芥中发现了一种基因，称为Hyponastic Leaves 1(HYL1)，它编码一种双链RNA结合蛋白。初步实验表明，HYL1蛋白参与miRNA的调控。在hyl1突变体中，几个miRNAs的水平降低，而在过度表达HYL1的植物中，miRNAs水平升高。相反，被预测为所研究miRNAs调控靶标的几个mRNAs的水平在突变体中升高，而在HYL1过度表达的植物中降低，这表明HYL1蛋白参与了miRNAs的生产或miRNA介导的mRNA水平的调节。Hyl1突变体具有多效性激素表型，对生长素和细胞分裂素的敏感性降低，对脱落酸过敏。本项目的目的是确定HYL1蛋白是否以及如何在miRNA调控基因表达中发挥作用。与HYL1相互作用的蛋白质将被鉴定，位于细胞中，并确定它们对miRNAs的产生和mRNA稳定性的影响。这种调节机制如何在基因表达的荷尔蒙调节中发挥作用，以及什么样的信号机制激活它也将被确定。这位首席研究员在为妇女和代表性不足的少数族裔提供培训机会方面一直处于领先地位，无论是在她的实验室还是在她的机构中都是如此。她还非常积极地向公众传播科学问题。这些科学成果可能会在生物技术中有实际应用。

It has recently been discovered that tiny RNA molecules, called microRNA (miRNA), are important in the development of both plants and animals, but little is yet known about how this newly-discovered regulatory mechanism operates. The principal investigator's laboratory has identified a gene in the well-characterized experimental plant Arabidopsis thaliana called Hyponastic leaves 1 (HYL1) that encodes a double-strand RNA-binding protein. Preliminary experiments suggest that the HYL1 protein participates in miRNA regulation. Levels of several miRNAs are reduced in a hyl1 mutant and elevated in a plant that overexpresses HYL1. Conversely, levels of several mRNAs predicted to be regulatory targets of the miRNAs examined are elevated in the mutant and reduced in HYL1 over-expressing plants, suggesting that the HYL1 protein is involved in either production of the miRNAs or in miRNA-mediated regulation of mRNA levels. The hyl1 mutant has a pleiotropic hormonal phenotype, exhibiting reduced sensitivity to auxin and cytokinin and hypersensitivity to abscisic acid. The objective of this project is to determine whether and how the HYL1 protein functions in miRNA regulation of gene expression. Proteins that interact with HYL1 will be identified, located in cells, and their effect on the production of miRNAs and mRNA stability determined. How this regulatory mechanism functions in the hormonal regulation of gene expression and what kinds of signaling mechanisms activate it will also be determined. The principal investigator has been a leader in providing training opportunities for women and underrepresented minorities, both in her lab and more widely at her institution. She is also very active in communicating science issues to the general public. The scientific results may have practical applications in biotechnology.