Identification of the Human Cytomegalovirus US27-Encoded Glycoprotein

Jessika Kluth

Department of Biological Sciences

Faculty Sponsor: Dr. Barry Margulies

(2004)

Human cytomegalovirus (HCMV), a member of the beta-herpesvirus family, encodes four homologues of cellular chemokine receptors, a subfamily of G protein-coupled receptors (GCRs). One of these, the glycoprotein product of HCMV open reading frame (ORF) UL33, has been identified in HCMV-infected cells and virus particles and shown to be heat-aggregatable and heavily N-glycosylated. Another, the product of ORF US28, has been functionally characterized as a beta-chemokine receptor. In this study we analyzed the glycoprotein encoded by HCMV US27. By Western immunoassays we determined that the US27-encoded glycoprotein appears in HCMV-infected cells and all three types of extracellular enveloped virus particles. The glycoprotein is heterogeneously N-glycosylated and resolves as two species in SDS-PAGE following treatment with peptide N-glycosidase F. Also consistent with its putative hydrophobic nature, both the recombinant and HCMV-expressed proteins aggregate when heated in the presence of SDS prior to electrophoresis in polyacrylamide gels, a phenomenon that can be abrogated in the presence of urea. Implications as to the existence of this glycoprotein and its impact on the virus life cycle will be discussed.

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Updated July 10, 2004