Date of Award

2014

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Microbiology and Immunology

Abstract

Coronaviruses are important human pathogens and have the potential to severely impact public health on an international scale. The emergence of SARS-CoV and MERS-CoV highlight the need for research to identify antivirals and vaccines against coronaviruses. To develop therapeutics against current and potentially emergent coronaviruses, I utilized two approaches targeting the proteases encoded within all coronaviruses. The papain-like protease and 3C-like protease of coronaviruses are responsible for cleaving viral polyproteins early during infection, and this step is required for viral replication. To quantitatively assess the inhibition by small-molecule compounds on MERS-CoV protease activity, I developed a luciferase-based biosensor to monitor protease cleavage within cells. Using this assay, I demonstrated that an inhibitor that is efficacious against SARS-CoV had activity against the 3C-like protease of MERS-CoV. In the second approach, I investigated the multifunctional papain-like protease of SARS-CoV, which has been implicated in pathogenesis by acting as a deubiquitinating (DUB) enzyme and blocking host immune responses. To determine if PLpro DUB activity is responsible for innate immune antagonism, I mutated residues predicted to interact with ubiquitin and discovered that when this interaction was interrupted, PLpro was unable to antagonize innate immune pathways. Engineering these mutations into SARS-COV may generate an attenuated virus that could stimulate a protective immune response in the absence of disease.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.

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