All ETDs from UAB

Advisory Committee Chair

William J Britt

Advisory Committee Members

Jim Collawn

Janusz H Kabarowski

Elliot J Lefkowitz

Peter Edward Jr Prevelige

Na Na

Document Type

Dissertation

Date of Award

2020

Degree Name by School

Doctor of Philosophy (PhD) Heersink School of Medicine

Abstract

Human cytomegalovirus (HCMV) is a ubiquitous pathogen that infects over 50% of the world’s population. HCMV infection is asymptomatic in healthy individuals, however can cause severe morbidity and mortality in individuals with compromised innate or adaptive immunity. As a complex virus that has been known for about 70 years, we are still in search of vaccines or effective treatments against it. HCMV genome encodes over 175 open reading frames with the function of majority proteins remains to be defined. A unique feature of HCMV among herpesvirus is the reorganization of cellular secretory pathway and membranes to form assembly compartment (AC). The mechanism of AC formation is unclear. A few well-studied envelope proteins including gpUL132 play critical roles in virus production. gpUL132 is a viral structural component conserved among all isolates of HCMV strains. To understand why gpUL132 is important and how it mediates virus production, we utilized a UL132 deletion HCMV virus (∆UL132). Characterization of the ∆UL132 mutant virus indicated that it was less infectious with a higher particle to infectious unit ratio. In addition, the viral assembly compartment (AC) failed to form in cells infected with the ∆UL132 mutant virus. Furthermore, using cell lines expressing chimeric proteins, we could demonstrate that the cytosolic domain of gpUL132 was sufficient to rescue AC formation and WT levels of virus production. Progeny virions from ∆UL132 infected cells expressing the cytosolic domain of gpUL132 exhibited similar particle to infectious unit ratio when compared to WT virus. In this study, we identified that gpUL132 is the first viral protein that mediates HCMV AC formation which results in defects in virus production. Our study highlights the importance of this envelope protein in virus-induced reorganization of intracellular membranes and AC formation in the assembly of infectious virus.

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