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

最近人们发现，微小的RNA分子，称为microRNA (miRNA)，在植物和动物的发育中都很重要，但对这种新发现的调节机制如何运作知之甚少。首席研究员的实验室已经在具有良好特征的实验植物拟南芥中发现了一个名为Hyponastic leaves 1 （HYL1）的基因，该基因编码双链rna结合蛋白。初步实验表明，HYL1蛋白参与miRNA调控。几种mirna的水平在hyl1突变体中降低，在hyl1过表达的植物中升高。相反，被预测为mirna调控靶点的几种mRNA水平在突变体中升高，而在HYL1过表达的植物中降低，这表明HYL1蛋白参与了mirna的产生或mirna介导的mRNA水平调节。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调控基因表达中起作用。与HYL1相互作用的蛋白将被鉴定，定位在细胞中，并确定其对mirna产生的影响和mRNA的稳定性。这种调节机制如何在激素调控基因表达中发挥作用，以及什么样的信号机制激活它也将被确定。这位首席研究员一直是为女性和少数族裔提供培训机会的领导者，无论是在她的实验室，还是在她所在的机构。她还非常积极地向公众传播科学问题。这些科学成果可能在生物技术方面有实际应用。

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.