Plus-stranded RNA viruses, which pose significant risks to human health and cause major losses for agriculture, depend heavily on host factors to replicate in infected cells. The roles of the subverted host factors in virus replication are currently poorly understood due to the lack of tractable virus-host systems. To advance rapidly our understanding of virus-host interactions during viral replication, the investigator has developed the powerful Tomato bushy stunt virus (TBSV)-yeast model system that led to the identification of numerous host factors affecting viral replication. This application is aimed at dissecting the roles of three RNA-binding host proteins: glyceraldehyde-3-phosphate dehydrogenase (GAPDH), the p68 DEAD-box RNA helicase homolog Dpb2 and translation elongation factor EF-1alpha (Tef1/2p), all of which bind to TBSV RNA and also known to interact with Hepatitis C virus, West Nile virus, dengue 4 virus and hepatitis A virus RNAs, suggesting that host factors might play similar roles in replication of these viruses. The advantages of tombusviruses for replication studies are numerous, including (i) their simple genomes and robust replication; (ii) similarity of TBSV replicase proteins to proteins of important pathogens, such as HCV, West Nile virus and other flaviviruses and pestiviruses; (iii) availability of in vitro replication assays developed in the Investigator's laboratory; and (iv) the development by the investigator of an efficient yeast-based TBSV replication system. In addition, a recent genome-wide screen including 95% of all yeast genes identified host genes that affected TBSV accumulation. Based on these advances, TBSV is a premium model system to study the roles of host factors in virus replication in eukaryotic hosts. Due to the central role of virus replication in viral pathogenesis, the proposed studies on host RNA-binding proteins involved in virus replication promise to advance our understanding of the viral replication process and to lead to identification of new antiviral targets. These and similar studies are needed urgently, because our current knowledge on host factors involved in virus replication and in viral pathogenesis is incomplete. Knowledge of virus-host interactions and the roles of host RNA-binding proteins might reveal new drug targets and lead to development of novel antiviral strategies. The tractable in vitro and in vivo TBSV system developed by the investigator could prove beneficial to studies of other, less amenable RNA viruses. ? ? ?

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Exploratory/Developmental Grants (R21)
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Study Section
Special Emphasis Panel (ZRG1-IDM-G (90))
Program Officer
Park, Eun-Chung
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University of Kentucky
Other Basic Sciences
Schools of Earth Sciences/Natur
United States
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Kovalev, Nikolay; Pogany, Judit; Nagy, Peter D (2012) A Co-Opted DEAD-Box RNA helicase enhances tombusvirus plus-strand synthesis. PLoS Pathog 8:e1002537
Kovalev, Nikolay; Barajas, Daniel; Nagy, Peter D (2012) Similar roles for yeast Dbp2 and Arabidopsis RH20 DEAD-box RNA helicases to Ded1 helicase in tombusvirus plus-strand synthesis. Virology 432:470-84
Huang, Tyng-Shyan; Nagy, Peter D (2011) Direct inhibition of tombusvirus plus-strand RNA synthesis by a dominant negative mutant of a host metabolic enzyme, glyceraldehyde-3-phosphate dehydrogenase, in yeast and plants. J Virol 85:9090-102
Sasvari, Zsuzsanna; Izotova, Lara; Kinzy, Terri Goss et al. (2011) Synergistic roles of eukaryotic translation elongation factors 1Býý and 1A in stimulation of tombusvirus minus-strand synthesis. PLoS Pathog 7:e1002438
Sharma, Monika; Sasvari, Zsuzsanna; Nagy, Peter D (2011) Inhibition of phospholipid biosynthesis decreases the activity of the tombusvirus replicase and alters the subcellular localization of replication proteins. Virology 415:141-52
Li, Zhenghe; Pogany, Judit; Tupman, Steven et al. (2010) Translation elongation factor 1A facilitates the assembly of the tombusvirus replicase and stimulates minus-strand synthesis. PLoS Pathog 6:e1001175
Barajas, Daniel; Nagy, Peter D (2010) Ubiquitination of tombusvirus p33 replication protein plays a role in virus replication and binding to the host Vps23p ESCRT protein. Virology 397:358-68
Sharma, Monika; Sasvari, Zsuzsanna; Nagy, Peter D (2010) Inhibition of sterol biosynthesis reduces tombusvirus replication in yeast and plants. J Virol 84:2270-81
Jiang, Yi; Cheng, Chi-Ping; Serviene, Elena et al. (2010) Repair of lost 5' terminal sequences in tombusviruses: Rapid recovery of promoter- and enhancer-like sequences in recombinant RNAs. Virology 404:96-105
Jiang, Yi; Li, Zhenghe; Nagy, Peter D (2010) Nucleolin/Nsr1p binds to the 3' noncoding region of the tombusvirus RNA and inhibits replication. Virology 396:10-20

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