UBC Theses and Dissertations
Viral protease disruption of host transcription and translation factors in the pathogenesis of coxsackievirus B3 induced viral myocarditis Hanson, Paul J.
Myocarditis, inflammation of the heart muscle, is a spectrum of conditions causing significant morbidity and mortality, yet scientific and clinical knowledge related to this entity is limited. One of the most common and best studied causes of myocarditis is infection by coxsackievirus B3 (CVB3). An improved understanding of the science behind CVB3 myocarditis is critical to establishing better diagnostic and therapeutic strategies for affected individuals. CVB3 infection redirects numerous cellular pathways from physiologic processes to viral replication, often mediated by viral proteases. Two viral targets in this process are death associated protein 5 (DAP5) and nuclear pore complex protein 98 (Nup98). DAP5 is a translation initiation factor specific to internal ribosome entry site (IRES) mediated translation. Nup98 is a component of the nuclear pore complex and a transcription factor. In this thesis, I hypothesize that viral proteases contribute to the pathogenesis of viral myocarditis through interaction with DAP5 and Nup98, redirecting translation and transcription towards viral replication. Using in vitro (plasmid expressed viral proteases), in situ (CVB3 infection in cell culture), and in vivo (mouse myocarditis model) models, I demonstrate that viral protease 2A is responsible for the cleavage of DAP5 and Nup98 during CVB3 infection. Both cleavage events I show to be integral to the viral lifecycle using over expression of recombinant fragments and siRNA inhibition of that expression. These results suggest two previously unidentified targets for improved diagnostics and therapeutics for myocarditis, both areas for future research.
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