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Functional Analyses of West Nile virus-Host Interactions
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- Author / Creator
- Xu, Zaikun
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West Nile virus (WNV) is a neurotropic, blood-borne flavivirus that can
cause serious neurological disease in humans and animals. While significant
progress has been made in identifying virus-encoded pathogenic determinants,
very little is known regarding how these viral proteins interact with host cell
proteins. Recent evidence suggests that in addition to its structural role in
packaging genomic RNA, the WNV capsid protein plays important roles in virus
host interactions and therefore, characterizing the interactions between capsid and
cellular proteins should contribute to our understanding of WNV disease and may
even reveal targets for antiviral therapy. Through an extensive yeast two-hybrid
screen, I identified DDX56, a novel WNV capsid-interacting nucleolar RNA
helicase. Experimental analyses revealed DDX56 is not required for production of
viral RNA or proteins, however, WNV virions secreted from DDX56-depleted
cells are 100 times less infectious than those produced in normal cells.
Collectively, these data suggest that DDX56 is critical for assembly of infectious
WNV virions possibly by facilitating the packaging of viral RNA.
I also investigated how WNV infection affects tight junctions in polarized
cells with the goal of understanding how the virus breaches the blood-brain
barrier to gain access to the central nervous system. While a number of recent
studies have documented that WNV infection negatively impacts the barrier
function of tight junctions, the intracellular mechanism by which this occurs is
poorly understood. Using a coordinated approach to understand the direct effects
of WNV infection on tight junction proteins in both epithelial and endothelial
cells, I discovered that WNV infection results in endocytosis of a specific subset
of tight junction membrane proteins including claudin-1 and JAM-1 followed by
microtubule-based transport to and degradation in lysosomes. Further studies into
this process could lead to therapeutic treatments that block viral spread and/or
design of attenuated vaccine strains. -
- Subjects / Keywords
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- Graduation date
- Fall 2013
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- Type of Item
- Thesis
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- Degree
- Doctor of Philosophy
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- License
- This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.