Poxviruses include a large family of DNA viruses capable of infecting and causing disease in humans. While the most notorious member variola, the causative agent of smallpox, was eradicated from natural infection, there are still concerns about a clandestine release during a biological attack. In addition, monkeypox and other members of the family have raised concern about epizootic infections that are capable of causing epidemic. Poxviruses produce two infectious forms, intracellular mature virus (IMV) and extracellular virus (EV). IMV make up the majority of progeny virions. EV are formed by the intracellular envelopment of IMV and are required for cell-to-cell spread and systemic infection. Only 8 viral proteins are known to be unique to the EV form. The long-term goal of this project is to understand the molecular mechanisms employed by orthopoxoviruses to envelope, transport, and release infectious EV. The immediate goal of this application is to understand how interactions with, and amongst the three major EV glycoproteins facilitate proper protein content in the EV envelop and how this effects systemic infection.
Our specific aims are; 1) Fine mapping of specific residues required for EV protein interaction, 2) To determine the hierarchy and spatial relationship between the EV protein interactions. 3) To determine the relationship between EV protein interaction EV envelope protein composition, infectious EV production, and pathogenesis in vivo. The conclusion of this study will provide information about the interaction between the three major orthopoxvirus glycoproteins (A33, A34, and B5) at the molecular, cellular and organismal levels. The results obtained will provide greater insight into the molecular mechanism poxviruses use to produce infectious EV and spread cell-to-cell in its host. In addition they will inform intelligent design decision when constructing recombinant poxvirus vectors for both vaccines and oncolytic platforms.

Public Health Relevance

Even though natural occurring smallpox was eradicated, concern for orthopoxviruses, ranging from a clandestine release of smallpox to outbreaks of epizootic infections such as monkeypox, still exist. Understanding the biology of poxviruses is still a priority not only for preventing epidemics but also for the intelligent creation of orthopoxvirus-based vaccines and oncolytic poxvirus platforms. The results from this study will provide key insights into poxvirus morphogenesis, which will in turn help in understanding both their life cycle and pathogenesis.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Research Project (R01)
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Special Emphasis Panel (ZRG1)
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Natarajan, Ramya
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University of Rochester
School of Medicine & Dentistry
United States
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Bryk, Peter; Brewer, Matthew G; Ward, Brian M (2018) Vaccinia Virus Phospholipase Protein F13 Promotes Rapid Entry of Extracellular Virions into Cells. J Virol 92:
Baker, Jonathon L; Ward, Brian M (2014) Development and comparison of a quantitative TaqMan-MGB real-time PCR assay to three other methods of quantifying vaccinia virions. J Virol Methods 196:126-32
Hollenbaugh, Joseph A; Gee, Peter; Baker, Jonathon et al. (2013) Host factor SAMHD1 restricts DNA viruses in non-dividing myeloid cells. PLoS Pathog 9:e1003481
Chan, Winnie M; Ward, Brian M (2012) Increased interaction between vaccinia virus proteins A33 and B5 is detrimental to infectious extracellular enveloped virion production. J Virol 86:8232-44
Chan, Winnie M; Ward, Brian M (2012) The A33-dependent incorporation of B5 into extracellular enveloped vaccinia virions is mediated through an interaction between their lumenal domains. J Virol 86:8210-20
Ward, Brian M (2011) The taking of the cytoskeleton one two three: how viruses utilize the cytoskeleton during egress. Virology 411:244-50
Chan, Winnie M; Ward, Brian M (2010) There is an A33-dependent mechanism for the incorporation of B5-GFP into vaccinia virus extracellular enveloped virions. Virology 402:83-93
Chan, Winnie M; Kalkanoglu, Aja E; Ward, Brian M (2010) The inability of vaccinia virus A33R protein to form intermolecular disulfide-bonded homodimers does not affect the production of infectious extracellular virus. Virology 408:109-18
Ward, Brian M (2009) Using fluorescent proteins to study poxvirus morphogenesis. Methods Mol Biol 515:1-11
Johnston, Sara C; Ward, Brian M (2009) Vaccinia virus protein F12 associates with intracellular enveloped virions through an interaction with A36. J Virol 83:1708-17

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