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Insights into the assembly of the tombusvirus replicase

Thursday, 2017, April 13 - 10:00
School of Life Sciences
Peter D.Nagy
Prof. Peter Nagy

Prof. Peter Nagy, professor at the Department of Plant Pathology, University of Kentucky, is a world authority on RNA virus replication and recombination.  Plus-stranded RNA viruses recruit cellular membranes and subvert cellular proteins involved in lipid biosynthesis to build viral replicase complexes (VRCs) and replication organelles. They use tombusviruses (TBSV), which are small (+)RNA viruses, as model plant viruses to study virus replication, recombination, and virus - host interactions using yeast (Saccharomyces cerevisiae) as a surrogate host. Several systematic genome-wide screens and global proteomic and lipidomic approaches have led to the identification of ~500 host proteins/genes that are implicated in TBSV replication. They characterized the role of a dozen co-opted host proteins, sterols and phosphatidylethanolamine in tombusvirus VRC assembly and viral RNA synthesis. They also present data that Tombusviruses induces the formation of membrane contact sites, where membranes are juxtaposed, to channel lipids to the replication sites. Using in vitro viral replication assay with artificial vesicles, they show stimulation of tombusvirus replication by PE and sterols. Finally, they show evidence that TBSV usurps the ESCRT machinery to form vesicle-like structures to build VRCs in a protected microenvironment involving peroxisomes, early endosomes and ER.