The picornaviruses are a family of small positive sense single stranded RNA viruses that cause a wide range of diseases at an annual cost well into the hundreds of million dollars. Members include acute hepatitis A virus, the heart disease causing coxsackie B3 virus, rhinoviruses that cause more than half the occurrences of the common cold, and the paralyzing poliovirus. These viruses share a common life cycle where their RNA replication and viral assembly occurs in large membrane anchored replication complexes assembled on the surfaces of vesicles derived from the endoplasmic reticulum. The replication process is driven by a virally encoded RNA dependent RNA polymerase, the 3Dpol protein, that is responsible the synthesis of all viral RNA. This research project is focused on the structure and assembly of viral replication centers, where we use poliovirus and coxsackievirus as our main experimental system. We have previously solved the crystal structures of the 3Dpol proteins from both these viruses and elucidated the molecular mechanism behind the proteolytic activation of these proteins upon cleavage from the viral 3CDpro precursor protein. We are continuing our studies of picronaviral replication proteins by focusing on the structural changes associated with the formation of the 3Dpol elongation complex and on understanding how mutations in the polymerase affect viral RNA replication both in vitro and in vivo. One new aspect of the project is focused on the structure of the membrane associated viral 2C protein that is responsible for host cell membrane rearrangements that lead to the formation of the vesicles upon which the replication complexes are formed.

Public Health Relevance

Poliovirus is the best-known member of a large family of viruses that have genomes made of RNA. These viruses carry a gene for a very specific RNA dependent RNA polymerase protein that is responsible for replicating the virus genome. The focus of this research project is to understand how this protein works during virus replication and find ways to interfere with its function, which will open the door to the development of antiviral drugs.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
High Priority, Short Term Project Award (R56)
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Virology - A Study Section (VIRA)
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Park, Eun-Chung
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Colorado State University-Fort Collins
Schools of Arts and Sciences
Fort Collins
United States
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Kempf, Brian J; Peersen, Olve B; Barton, David J (2016) Poliovirus Polymerase Leu420 Facilitates RNA Recombination and Ribavirin Resistance. J Virol 90:8410-21
Kempf, Brian J; Kelly, Michelle M; Springer, Courtney L et al. (2013) Structural features of a picornavirus polymerase involved in the polyadenylation of viral RNA. J Virol 87:5629-44
Gnadig, Nina F; Beaucourt, Stephanie; Campagnola, Grace et al. (2012) Coxsackievirus B3 mutator strains are attenuated in vivo. Proc Natl Acad Sci U S A 109:E2294-303
Gong, Peng; Peersen, Olve B (2010) Structural basis for active site closure by the poliovirus RNA-dependent RNA polymerase. Proc Natl Acad Sci U S A 107:22505-10
Hobdey, Sarah E; Kempf, Brian J; Steil, Benjamin P et al. (2010) Poliovirus polymerase residue 5 plays a critical role in elongation complex stability. J Virol 84:8072-84