Key role of the multifunctional translation elongation factor in virus replication.

Replication is the central step in the infectious cycles of plus-stranded RNA viruses, which cause many devastating diseases in plants, animals and humans. These viruses replicate inside the infected cells by co-opting an unknown number of host proteins and reprogramming several cellular pathways. In spite of the significance of host proteins in viral pathogenesis, our current knowledge on host factors subverted for virus replication is incomplete. In order to advance our understanding of the key role of host factors in viral replication, the PI has recently developed a powerful yeast-based replication system for tombusviruses (Tomato bushy stunt virus, TBSV), which are plant viruses widespread in crops and aquatic environments. Recent genome-wide genomics and proteomics screens by the PI led to the identification of 250 host genes affecting TBSV replication/recombination, demonstrating the complex nature of host-virus interactions. Altogether, the availability of in vitro replication systems and development of yeast for efficient replication of the TBSV RNA in combination with large datasets from genomics and proteomics screens from the PI..s lab makes tombusviruses the best suited to study host factors involved in viral RNA replication. This proposal is aimed at addressing the role of the multifunctional translation elongation factor 1A (eEF1A), which is a permanent resident in the viral replicase complex and plays a key role in TBSV replication. Since eEF1A likely affects replication of a large number of plant and animal viruses, major progress with tombusviruses would be highly advantageous to other viruses as well. Altogether, characterization of the multiple functions performed by eEF1A in virus replication will lead to better understanding of the replication process and development of novel antiviral strategies. Intellectual merit of the proposal: Pioneering work by the PI will contribute key knowledge to understanding how host factors participate in viral pathogenesis. The work will unravel the functions of eEF1A, which have been implicated in replication of a large number of viruses. The proposed innovative approaches including yeast and plant assays developed for tombusviruses as well as the powerful cell-free TBSV replication assay in yeast extracts will likely lead to major new insights into virus replication and viral pathogenesis and will have a considerable impact on our understanding of the mechanism that transforms the host cells into “viral factories”. Broader impacts of the proposed activity: Pioneering research on tombusvirus replication could immensely help other scientists working with less tractable, but devastating viral pathogens for which similar studies are currently not yet feasible. Dissection of the role of eEF1A in viral pathogenesis and disease development will facilitate future antiviral approaches and treatments to reduce the effect of viral diseases. Education component: High school and undergraduate students are currently actively participating in research in the PI..s laboratory, which led to research papers. They are exposed to highly innovative research and this experience provides them an invaluable learning experience. This research will promote interdisciplinary (plant pathology, biochemistry, cell biology, genetics) learning. The research holds promise of benefiting society by leading to groundbreaking results in the area of virus replication and pathogenesis.