The molecular mechanisms involved in poxvirus entry into cells remain perplexing. Our goal is to dissect these mechanisms by focusing on the envelope proteins involved in entry of three orthopoxviruses: vaccinia (VACV), variola (VARV) and monkeypox (MPXV). The accidental or intentional release of VARV, coupled with the potential of MPXV to become a more efficient human pathogen, underscore the need for further investigation of these viruses in terms of their biodefense importance and as emerging infectious agents. The cell receptor(s) and the viral receptor-binding protein(s) for poxviruses are unknown. Our preliminary data suggest that the MV protein L1 is a receptor binding protein that may trigger fusion that is carried out by the virus fusion complex. We found that a soluble form of L1 binds to cells independently of glycosaminoglycans and blocks virus entry, suggesting it competes with virion associated L1 for a cell receptor.
In Aim 1, we will map regions on L1 critical for its function in entry and identify the cellular receptor(s) to which it binds. We will determine which residues of L1 are involved in its ability to block virus entry using structure based mutagenesis. Similar studies will be done in collaboration with colleagues at CDC for MPXV and VARV. We will use two approaches to identify the cell receptor(s) for L1. First, we will use L1 itself to try to "fish out" the receptor from susceptible cells. Second, we will take a more unbiased approach using RNAi to screen for proteins that are important in VACV entry, focusing particularly on ones that may target L1.
In Aim 2 we will study how the MV envelope proteins function in poxvirus entry. We will use assays to follow events that occur after receptor binding using a novel confocal-FACS technology. We will employ bimolecular fluorescence complementation to study interactions between VACV envelope proteins in intact cells with the goal of relating them to VACV entry/fusion. Our studies should provide the molecular details of both the viral and cellular factors involved in poxvirus entry. Additionally, we may identify novel targets for developing small molecule inhibitors of poxvirus entry.

Public Health Relevance

Our goal is to understand how poxviruses gain entry into target cells of their host. This complex process involves proteins on the surface of the virus as well as cell receptors that interact with them. An understanding of this complex process may identify important targets of new therapeutics against emerging infections such as monkeypox and against possible threats of a smallpox outbreak.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Specialized Center--Cooperative Agreements (U54)
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Special Emphasis Panel (ZAI1-DDS-M)
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University of Maryland Baltimore
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Freedman, John C; Theoret, James R; Wisniewski, Jessica A et al. (2015) Clostridium perfringens type A-E toxin plasmids. Res Microbiol 166:264-79
Li, Jihong; McClane, Bruce A (2014) Contributions of NanI sialidase to Caco-2 cell adherence by Clostridium perfringens type A and C strains causing human intestinal disease. Infect Immun 82:4620-30
Moy, Ryan H; Gold, Beth; Molleston, Jerome M et al. (2014) Antiviral autophagy restrictsRift Valley fever virus infection and is conserved from flies to mammals. Immunity 40:51-65
Cuevas, Christian D; Ross, Susan R (2014) Toll-like receptor 2-mediated innate immune responses against Junín virus in mice lead to antiviral adaptive immune responses during systemic infection and do not affect viral replication in the brain. J Virol 88:7703-14
Boyd, Mary Adetinuke; Tennant, Sharon M; Saague, Venant A et al. (2014) Serum bactericidal assays to evaluate typhoidal and nontyphoidal Salmonella vaccines. Clin Vaccine Immunol 21:712-21
Su, Yi-Hsuan; Tsegaye, Mikiyas; Varhue, Walter et al. (2014) Quantitative dielectrophoretic tracking for characterization and separation of persistent subpopulations of Cryptosporidium parvum. Analyst 139:66-73
Xu, Jie; Cherry, Sara (2014) Viruses and antiviral immunity in Drosophila. Dev Comp Immunol 42:67-84
Uzal, Francisco A; Freedman, John C; Shrestha, Archana et al. (2014) Towards an understanding of the role of Clostridium perfringens toxins in human and animal disease. Future Microbiol 9:361-77
Weir, Dawn L; Laing, Eric D; Smith, Ina L et al. (2014) Host cell virus entry mediated by Australian bat lyssavirus G envelope glycoprotein occurs through a clathrin-mediated endocytic pathway that requires actin and Rab5. Virol J 11:40
Weir, Dawn L; Annand, Edward J; Reid, Peter A et al. (2014) Recent observations on Australian bat lyssavirus tropism and viral entry. Viruses 6:909-26

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