Dissertation
Herpes simplex virus cytoplasmic assembly center as a tool for viral egress research and therapeutic development
University of Iowa
Doctor of Philosophy (PhD), University of Iowa
Summer 2022
DOI: 10.25820/etd.006608
Abstract
Herpes simplex virus (HSV) is a neuroinvasive virus that has been used as a model organism for studying common properties of all herpesviruses. HSV induces host organelle rearrangement and forms multiple, dispersed assembly compartments in epithelial cells, of which identity is controversial, with evidence supporting either Golgi- or recycling endosome-derived membranes. My works showed that HSV forms a visually distinct unitary cytoplasmic viral assembly center (cVAC) in both cancerous and primary neuronal cells that concentrates viral structural proteins and is a major site of capsid envelopment. The HSV cVAC also concentrates host membranes that are important for viral assembly, including Golgi- and recycling endosome-derived membranes. The formation and/or maintenance of HSV cVAC depends on intact microtubule network, microtubule associated motor dynein, and a viral tegument protein, pUL51.Further studies discovered that HSV cVAC has two layers of organization: (i) tethering of Golgi- and recycling endosome-derived membranes in a nocodazole-resistant manner, and (ii) concentration of these tethered structures around the centrosome. This vesicle tethering event was not observed in uninfected cells, and depends on viral protein pUL51, suggesting that organelle trafficking in infected cells is distinct from uninfected cells.
Lastly, we identified an interaction between pUL51 and host dynein cargo adaptor dynactin. The interaction sequence was mapped to a.a. 90-125 in pUL51. The viral mutant with a.a 90-125 deleted in pUL51 had small growth defect but significant spread defect. Based on these, we designed pUL51 a.a. 90-125-containing peptides that inhibited HSV spread in cell culture in pUL51-dependent manner.
Details
- Title: Subtitle
- Herpes simplex virus cytoplasmic assembly center as a tool for viral egress research and therapeutic development
- Creators
- Shaowen White
- Contributors
- Richard Roller (Advisor)Hillel Haim (Committee Member)Wendy Maury (Committee Member)Stanley Perlman (Committee Member)Charles Yeaman (Committee Member)
- Resource Type
- Dissertation
- Degree Awarded
- Doctor of Philosophy (PhD), University of Iowa
- Degree in
- Microbiology
- Date degree season
- Summer 2022
- Publisher
- University of Iowa
- DOI
- 10.25820/etd.006608
- Number of pages
- xii, 193 pages
- Copyright
- Copyright 2022 Shaowen White
- Language
- English
- Description illustrations
- illustrations (chiefly color), charts
- Description bibliographic
- Includes bibliographical references (pages 169-193).
- Public Abstract (ETD)
- Herpes Simplex Virus (HSV) is a ubiquitous virus that infects 40%-90% of the global population and is a leading cause of blindness and encephalitis. The only treatment for HSV infections currently is acyclovir and its derivatives, which all target a single mechanism–viral DNA replication. This lack of alternative therapeutics has led to the emergence of drug resistant HSV. Meanwhile, the cytoplasmic assembly of HSV is a process that contains ample druggable targets. Disrupting the function of any one of the ~33 cytoplasmic assembly proteins typically result in aborted or attenuated infections in vivo. However, the function and mechanism of many of these proteins are poorly understood. The difficulty in the study of the HSV cytoplasmic assembly stems from the cell model: in commonly used cancerous or epithelial cells, host organelles are drastically modified so that they become unrecognizable. My works described HSV rearrangement of host membranes in a cell type-dependent manner and the formation of a concentrate viral factory in infected neuronal cells. The viral factory provides a visual landmark to distinguish components that are directly involved in HSV assembly. By using this factory as a tool, my works revealed mechanistic details of HSV assembly that cannot be addressed by epithelial cell models, including a nocodazole-resistant tethering between organelles in infected cells. Building on these discoveries, a novel interaction between a HSV spread factor pUL51 and a host motor protein was discovered, which was exploited to develop an inhibitor of HSV spread in cell cultures.
- Academic Unit
- Microbiology and Immunology
- Record Identifier
- 9984285346602771
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