Presenter Information

Charlotte LangnerFollow

Presentation Type

Presentation

Faculty Mentor’s Full Name

Brent Ryckman

Faculty Mentor’s Department

Division of Biological Sciences

Abstract

Human cytomegalovirus (HCMV) infection is asymptomatic in healthy individuals, but can cause severe disease in immunocompromised people. On the virus envelope, glycoproteins gH/gL form a trimer with gO or a pentamer with UL128-131. These glycoprotein complexes interact with receptors on the host cells to initiate viral fusion and thus are promising sites for vaccine development. The levels of trimer and pentamer significantly influence the infectivity of the virions. Clinical strains of HCMV differ in the relative amounts of trimer and pentamer in the virus particles, however, the mechanism controlling the level of trimer and pentamer is still not clear. My previous research showed that overexpressing UL128-131 results in increased pentamer and decreased trimer levels, suggesting that gO and UL128-131 compete in binding to gH/gL, and that the relative amounts of trimer and pentamer are driven by the expression levels of gO and UL128-131 proteins. The amino acid sequence of gH/gL are highly conserved, whereas gO shows substantial diversity across strains. To elucidate how the diversity of gO affects the formation of trimer and pentamer, we have prepared a library of mutants with gOs from different HCMV strains swapped into one strain, TR. We noted that swapping gO from strain TN into TR results in slow viral replication suggesting incompatibility between gH/gL and gO from different strains. I am conducting an experiment to test whether expressing TNgO in the cell during TR replication will affect the levels of trimer and pentamer as well as the infectivity of the progeny virions. Fibroblasts were infected with TR (with a GFP reporter gene) and subsequently infected with non-replicating adenovirus delivering genes for either TRgO, TNgO, or a control, and analysis is in progress. Progeny virions will be characterized by glycoprotein composition and infectivity using Western blots, qPCR, and flow cytometry.

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Life Sciences

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Apr 17th, 9:20 AM Apr 17th, 9:40 AM

Effect of expression level and amino acid sequence on HCMV glycoprotein complexes

UC 330

Human cytomegalovirus (HCMV) infection is asymptomatic in healthy individuals, but can cause severe disease in immunocompromised people. On the virus envelope, glycoproteins gH/gL form a trimer with gO or a pentamer with UL128-131. These glycoprotein complexes interact with receptors on the host cells to initiate viral fusion and thus are promising sites for vaccine development. The levels of trimer and pentamer significantly influence the infectivity of the virions. Clinical strains of HCMV differ in the relative amounts of trimer and pentamer in the virus particles, however, the mechanism controlling the level of trimer and pentamer is still not clear. My previous research showed that overexpressing UL128-131 results in increased pentamer and decreased trimer levels, suggesting that gO and UL128-131 compete in binding to gH/gL, and that the relative amounts of trimer and pentamer are driven by the expression levels of gO and UL128-131 proteins. The amino acid sequence of gH/gL are highly conserved, whereas gO shows substantial diversity across strains. To elucidate how the diversity of gO affects the formation of trimer and pentamer, we have prepared a library of mutants with gOs from different HCMV strains swapped into one strain, TR. We noted that swapping gO from strain TN into TR results in slow viral replication suggesting incompatibility between gH/gL and gO from different strains. I am conducting an experiment to test whether expressing TNgO in the cell during TR replication will affect the levels of trimer and pentamer as well as the infectivity of the progeny virions. Fibroblasts were infected with TR (with a GFP reporter gene) and subsequently infected with non-replicating adenovirus delivering genes for either TRgO, TNgO, or a control, and analysis is in progress. Progeny virions will be characterized by glycoprotein composition and infectivity using Western blots, qPCR, and flow cytometry.