Structure and Function of Plant Virus 3' RNA Translational Enhancer Elements

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Plant viruses affect a number of food crops leading to severe economic and food supply problems. Barley yellow dwarf virus (BYDV) and maize necrotic streak virus (MNeSV) are aphid-borne threats to cereal crops worldwide. These positive strand RNA viruses are some of the most efficiently translated mRNA known, and can therefore be co-opted in biotechnology for low-cost production of proteins; however, emerging viruses remain a severe problem affecting crops. This project will address major roadblocks in developing new anti-viral strategies by determining mechanistic details of viral protein synthesis that identify target steps for intervention. The project also provides excellent training for students from high school through graduate levels. A structured summer research program will be developed as a model for offering research opportunities to larger numbers of undergraduates at the institution. Many of these students are from under-represented minorities and their participation will contribute to a diverse and well-trained scientific workforce. This project will investigate critical aspects in the selection of mRNA for translation and assembly of an initiation complex. The role of protein synthesis initiation factor 3 (eIF3) will be determined by using fluorescence spectroscopy to measure affinity and kinetics of binding to the translation enhancer element, and structural probing to determine how it remodels RNA. The mechanism of ribosome recruitment will be investigated by single molecule fluorescence, including comparative analysis of BYDV and the structurally simpler MNeSV to understand common themes in viral protein synthesis. Cryo-EM experiments and chemical probing will be employed to determine structural details about the protein-RNA interactions. This comprehensive approach is expected to provide a better understanding of how plant viruses outcompete host mRNA in translation. Since these mechanisms likely occur in other eukaryotic systems and regulate translation under stress conditions, the results of this project are expected to be broadly applicable.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.