The Role of Host Proteins in HC-Pro Suppression of Silencing

University South Carolina Research Foundation, Columbia SC

Investigators

Abstract

This project is part of a long-term effort to understand the mechanism of action of a plant viral protein, helper component proteinase (HC-Pro), which is a potent suppressor of RNA silencing in plants. RNA silencing is used by plants and animals to defend against viral infection and to control expression of the organism's own genes. Therefore, HC-Pro not only blocks anti-viral defense, but also interferes with an important genetic regulatory mechanism in the host plant. The goal of this project is to determine the role of host plant proteins in HC-Pro function, using genetic, biochemical, and molecular approaches. The project focuses on a novel calmodulin-like protein that interacts with HC-Pro and is itself a suppressor of silencing when over-expressed in plants. Because calmodulin and related proteins bind calcium, which is used as a signal in many biological processes, the work is poised to provide new insights into the role of calcium signaling in the regulation of silencing as well as to contribute significantly to understanding the mechanisms by which viruses usurp endogenous control systems for counter-defensive purposes. The outcomes of this project should have a major impact on the field because investigation into the role of host proteins in viral suppression of silencing has been largely neglected and the role of calcium signaling has not been studied at all. The research should also contribute significantly to advancements in antiviral defense strategies and in biotechnologies that make use of plants. The project will provide summer internships for two students to participate in the research and will emphasize participation of female and minority students. Senior project personnel will participate actively in both teaching and mentoring these interns to help provide them with an accessible pathway into the research sciences.