Synthesis and processing of the equine herpesvirus 1 glycoprotein M.

Abstract

In a previous report, the function of the equine herpesvirus 1 (EHV-1) glycoprotein M (gM) homolog was investigated. It was shown that EHV-1 gM is involved in both virus entry and direct cell-to-cell spread of infection (N. Osterrieder et al., J. Virol. 70, 4110-4115, 1996). In this study, experiments were conducted to analyze the synthesis, posttranslational processing, and the putative ion channel function of EHV-1 gM. It was demonstrated that EHV-1 gM is synthesized as an Mr 44,000 polypeptide, which is cotranslationally N-glycosylated to an Mr 46,000-48,000 glycoprotein. The Mr 46,000-48,000 gM moiety is processed to an Mr 50,000-55,000 glycoprotein, which is resistant to treatment with endoglycosidase H, indicating that processing occurs in the Golgi network. EHV-1 gM forms a dimer in infected cells and the virion, as was demonstrated by the presence of an Mr 105,000-110,000 gM-containing band in electrophoretically separated lysates of infected cells and purified extracellular virions. The Mr 105,000-110,000 protein band containing gM was also observed in lysates of cells that had been transfected with EHV-1 gM DNA. The translation of EHV-1 gM is initiated at the first in-frame methionine of the gM open reading frame as shown by transient transfection experiments of full-length gM and a truncated gM lacking the aminoterminal 83 amino acids. Functional expression of EHV-1 gM in Xenopus laevis oocytes together with voltage-clamp analyses demonstrated that gM per se does not exhibit ion channel activity as had been speculated from the predicted structure of the polypeptide.

• Authors: N Osterrieder, A Neubauer, B Fakler, C Brandmüller, C Seyboldt, O R Kaaden, J D Baines
• Journal: Virology (Virology) Vol. 232 Issue 1 Pg. 230-9 (May 26 1997) ISSN: 0042-6822 [Print] UNITED STATES
• PMID: 9185606 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Ion Channels
• Viral Proteins
• Methionine

Topics

• Animals
• COS Cells
• Electrophoresis, Gel, Pulsed-Field
• Glycosylation
• Herpesvirus 1, Equid (metabolism)
• Ion Channels (metabolism)
• Kinetics
• Methionine (metabolism)
• Protein Biosynthesis
• Protein Processing, Post-Translational
• Viral Proteins (biosynthesis, metabolism)