Intellectual Merit: Long range RNA-RNA interactions are well documented for virtually all mRNA. Most cellular mRNAs employ a 5' cap and a 3' poly (A) tail, both of which play key roles in translation of the mRNA. However interactions involving internal ribosome entry sites and 3' RNA elements are also beginning to be identified in cellular RNAs, especially under conditions where overall translation is compromised. A major deviation from the classical model of translation occurs for those mRNAs (often viral) that lack either a cap structure, poly (A) tail or both. One such virus is barley yellow dwarf virus (BYDV), one of the most widespread and economically important viruses of barley. BYDV contains an unusual RNA structure in the 3' untranslated region of the mRNA that interacts with a stem-loop in the 5' untranslated region. This long-range interaction promotes efficient translation of the viral mRNA, but the mechanism is not well understood. This project will explore the interaction of the BYDV RNA with eIF4F, a protein that controls the rate-limiting step for translation initiation. The specificity of ribosome binding to the BYDV RNA will also be determined by "toeprint" analysis. Taken together, these data will lead to a better understanding of how viral mRNA is able to out-compete host cell messenger RNA for effective viral infection.
Broader Impacts: These experiments will provide excellent training for students from high school through graduate school in both biochemical and quantitative measurements. Interactions will continue with faculty from a local high school and from Borough of Manhattan Community College (a Hispanic serving institution) to help improve research for faculty and their students. Many of the students involved in the PI's research in the past have been from underrepresented minority groups, and minority students will also be included in this project. These students will contribute to a diverse and well-trained workforce in science and technology. An additional activity will be the redesign of the advanced lab curriculum to include inquiry-based research and to provide a research experience for more students. The research will have broad scientific impact through its use of a plant virus model for studying a key step in regulation of gene expression. Plant viral diseases affect a significant number of food crops world-wide and can have severe impact both on economic conditions and food supply. There is a potential to use information from this research not only to control viruses but also to develop systems to produce desired proteins which are nutritionally beneficial or economically useful.
Barley yellow dwarf virus (BYDV) is one of the economically most devastating viruses for cereal crops. BYDV attacks wheat, oats, rice and other cereal crops leading to severe yield losses. In this project we have investigated how the virus utilizes host cell machinery to make viral proteins. We have found that unlike host mRNA which is "read" by ribosomes starting the 5' end of the mRNA and reading to the 3' end, BYVD captures host cell machinery at the 3' end of the mRNA and subsequently transfers the ribosome to the 5' end for translation. The mechanism of this transfer is under investigation. By identifying a unique step in this process, we have identified a potential target for control of the virus. Since the host cell does need to perform this step, inhibition would inhibit viral protein synthesis without halting host cell protein synthesis. Understanding the molecular basis of this process will allow design of small molecules or other means of inhibiting the virus. This project has provided training in modern biophyscial and biochemical techniques for graduate students, post-doctoral associates, undergraduates and high school students. The diversity of this group of students has helped to create a more diverse and technically trained workforce.
