scholarly journals Venezuelan Equine Encephalitis Virus Capsid Protein Inhibits Nuclear Import in Mammalian but Not in Mosquito Cells

2008 ◽  
Vol 82 (8) ◽  
pp. 4028-4041 ◽  
Author(s):  
Svetlana Atasheva ◽  
Natalia Garmashova ◽  
Ilya Frolov ◽  
Elena Frolova
Keyword(s):  
Capsid Protein ◽  
Nuclear Import ◽  
Critical Role ◽  
The United States ◽  
Venezuelan Equine Encephalitis Virus ◽  
Encephalitis Virus ◽  
Venezuelan Equine Encephalitis ◽  
Equine Encephalitis Virus ◽  
Small Proteins ◽  
Mosquito Cells

ABSTRACT Venezuelan equine encephalitis virus (VEEV) represents a continuous public health threat in the United States. It has the ability to cause fatal disease in humans and in horses and other domestic animals. We recently demonstrated that replicating VEEV interferes with cellular transcription and uses this phenomenon as a means of downregulating a cellular antiviral response. VEEV capsid protein was found to play a critical role in this process, and its ∼35-amino-acid-long peptide, fused with green fluorescent protein, functioned as efficiently as did the entire capsid. We detected a significant fraction of VEEV capsid associated with nuclear envelope, which suggested that this protein might regulate nucleocytoplasmic trafficking. In this study, we demonstrate that VEEV capsid and its N-terminal sequence efficiently inhibit multiple receptor-mediated nuclear import pathways but have no effect on the passive diffusion of small proteins. The capsid protein of the Old World alphavirus Sindbis virus and the VEEV capsid, with a previously defined frameshift mutation, were found to have no detectable effect on nuclear import. Importantly, the VEEV capsid did not noticeably interfere with nuclear import in mosquito cells, and this might play a critical role in the ability of the virus to develop a persistent, life-long infection in mosquito vectors. These findings demonstrate a new aspect of VEEV-host cell interactions, and the results of this study are likely applicable to other New World alphaviruses, such as eastern and western equine encephalitis viruses.

scholarly journals The SD1 Subdomain of Venezuelan Equine Encephalitis Virus Capsid Protein Plays a Critical Role in Nucleocapsid and Particle Assembly

2015 ◽  
Vol 90 (4) ◽  
pp. 2008-2020 ◽  
Author(s):  
Josephine M. Reynaud ◽  
Valeria Lulla ◽  
Dal Young Kim ◽  
Elena I. Frolova ◽  
Ilya Frolov
Keyword(s):  
Capsid Protein ◽  
Driving Forces ◽  
Critical Role ◽  
Venezuelan Equine Encephalitis Virus ◽  
Encephalitis Virus ◽  
Venezuelan Equine Encephalitis ◽  
Particle Assembly ◽  
Equine Encephalitis Virus ◽  
Amino Terminal ◽  
Virus Capsid Protein

ABSTRACTVenezuelan equine encephalitis virus (VEEV) is an important human and animal pathogen, for which no safe and efficient vaccines or therapeutic means have been developed. Viral particle assembly and budding processes represent potential targets for therapeutic intervention. However, our understanding of the mechanistic process of VEEV assembly, RNA encapsidation, and the roles of different capsid-specific domains in these events remain to be described. The results of this new study demonstrate that the very amino-terminal VEEV capsid-specific subdomain SD1 is a critical player in the particle assembly process. It functions in a virus-specific mode, and its deletion, mutation, or replacement by the same subdomain derived from other alphaviruses has strong negative effects on infectious virus release. VEEV variants with mutated SD1 accumulate adaptive mutations in both SD1 and SD2, which result in a more efficiently replicating phenotype. Moreover, efficient nucleocapsid and particle assembly proceeds only when the two subdomains, SD1 and SD2, are derived from the same alphavirus. These two subdomains together appear to form the central core of VEEV nucleocapsids, and their interaction is one of the driving forces of virion assembly and budding. The similar domain structures of alphavirus capsid proteins suggest that this new knowledge can be applied to other alphaviruses.IMPORTANCEAlphaviruses are a group of human and animal pathogens which cause periodic outbreaks of highly debilitating diseases. Despite significant progress made in understanding the overall structure of alphavirus and VEEV virions, and glycoprotein spikes in particular, the mechanistic process of nucleocapsid assembly, RNA encapsidation, and the roles of different capsid-specific domains in these processes remain to be described. Our new data demonstrate that the very amino-terminal subdomain of Venezuelan equine encephalitis virus capsid protein, SD1, plays a critical role in the nucleocapsid assembly. It functions synergistically with the following SD2 (helix I) and appears to form a core in the center of nucleocapsid. The core formation is one of the driving forces of alphavirus particle assembly.

scholarly journals Application of In Silico and HTS Approaches to Identify Nuclear Import Inhibitors for Venezuelan Equine Encephalitis Virus Capsid Protein: A Case Study

2020 ◽  
Vol 8 ◽  
Author(s):  
Sharon Shechter ◽  
David R. Thomas ◽  
David A. Jans
Keyword(s):  
Drug Design ◽  
Nuclear Import ◽  
In Silico ◽  
Venezuelan Equine Encephalitis Virus ◽  
Encephalitis Virus ◽  
Venezuelan Equine Encephalitis ◽  
Nuclear Targeting ◽  
Equine Encephalitis Virus ◽  
Screening Approaches

The development of new drugs is costly and time-consuming, with estimates of over $US1 billion and 15 years for a product to reach the market. As understanding of the molecular basis of disease improves, various approaches have been used to target specific molecular interactions in the search for effective drugs. These include high-throughput screening (HTS) for novel drug identification and computer-aided drug design (CADD) to assess the properties of putative drugs before experimental work begins. We have applied conventional HTS and CADD approaches to the problem of identifying antiviral compounds to limit infection by Venezuelan equine encephalitis virus (VEEV). Nuclear targeting of the VEEV capsid (CP) protein through interaction with the host nuclear import machinery has been shown to be essential for viral pathogenicity, with viruses incapable of this interaction being greatly attenuated. Our previous conventional HTS and in silico structure-based drug design (SBDD) screens were successful in identifying novel inhibitors of CP interaction with the host nuclear import machinery, thus providing a unique opportunity to assess the relative value of the two screening approaches directly. This focused review compares and contrasts the two screening approaches, together with the properties of the inhibitors identified, as a case study for parallel use of the two approaches to identify antivirals. The utility of SBDD screens, especially when used in parallel with traditional HTS, in identifying agents of interest to target the host–pathogen interface is highlighted.

scholarly journals Antibody to the E3 Glycoprotein Protects Mice against Lethal Venezuelan Equine Encephalitis Virus Infection

2010 ◽  
Vol 84 (24) ◽  
pp. 12683-12690 ◽  
Author(s):  
Michael D. Parker ◽  
Marilyn J. Buckley ◽  
Vanessa R. Melanson ◽  
Pamela J. Glass ◽  
David Norwood ◽  
...  
Keyword(s):  
Critical Role ◽  
Passive Immunization ◽  
Venezuelan Equine Encephalitis Virus ◽  
Encephalitis Virus ◽  
Progeny Virus ◽  
Virus Infectivity ◽  
Venezuelan Equine Encephalitis ◽  
Equine Encephalitis Virus ◽  
Furin Cleavage Site ◽  
Infected Cells

ABSTRACT Six monoclonal antibodies were isolated that exhibited specificity for a furin cleavage site deletion mutant (V3526) of Venezuelan equine encephalitis virus (VEEV). These antibodies comprise a single competition group and bound the E3 glycoprotein of VEEV subtype I viruses but failed to bind the E3 glycoprotein of other alphaviruses. These antibodies neutralized V3526 virus infectivity but did not neutralize the parental strain of Trinidad donkey (TrD) VEEV. However, the E3-specific antibodies did inhibit the production of virus from VEEV TrD-infected cells. In addition, passive immunization of mice demonstrated that antibody to the E3 glycoprotein provided protection against lethal VEEV TrD challenge. This is the first recognition of a protective epitope in the E3 glycoprotein. Furthermore, these results indicate that E3 plays a critical role late in the morphogenesis of progeny virus after E3 appears on the surfaces of infected cells.

scholarly journals Expression and Self-Assembly of Norwalk Virus Capsid Protein from Venezuelan Equine Encephalitis Virus Replicons

2002 ◽  
Vol 76 (6) ◽  
pp. 3023-3030 ◽  
Author(s):  
Ralph S. Baric ◽  
Boyd Yount ◽  
Lisa Lindesmith ◽  
Patrick R. Harrington ◽  
Shermalyn R. Greene ◽  
...  
Keyword(s):  
Capsid Protein ◽  
Self Assembly ◽  
Mammalian Cells ◽  
Venezuelan Equine Encephalitis Virus ◽  
Encephalitis Virus ◽  
Norwalk Virus ◽  
Venezuelan Equine Encephalitis ◽  
Equine Encephalitis Virus ◽  
Large Numbers ◽  
Virus Capsid Protein

ABSTRACT The Norwalk virus (NV) capsid protein was expressed using Venezuelan equine encephalitis virus replicon particles (VRP-NV1). VRP-NV1 infection resulted in large numbers of recombinant NV-like particles that were primarily cell associated and were indistinguishable from NV particles produced from baculoviruses. Mutations located in the N-terminal and P1 domains of the NV capsid protein ablated capsid self-assembly in mammalian cells.

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