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

Pennsylvania State Univ University Park, University Park PA

Investigators

Abstract

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.