Biochemical and functional analysis of the Borna disease virus G protein

J Virol. 1997 Jan;71(1):331-6. doi: 10.1128/JVI.71.1.331-336.1997.

Abstract

The Borna disease virus (BDV) antigenome is comprised of five major open reading frames (ORFs). Products have been reported only for ORFs I, II, and III, encoding N (p40), P (p24/p23), and M (gp18), respectively. ORF IV predicts a 57-kDa protein with several potential glycosylation sites. Analysis of radiolabeled extracts from BDV-infected C6 cells and BHK-21 cells transfected with a Semliki Forest virus vector that contains ORF IV demonstrated the presence of a 94-kDa protein (G protein) which was sensitive to tunicamycin, endoglycosidase F/N-glycosidase, and endoglycosidase H but not to O-glycosidase. Sera from BDV-infected rats detected the G protein and had neutralization activity that was reduced following immunoadsorption with the G protein. Preincubation of cells with the G protein interfered with BDV infectivity. This effect was enhanced by treatment of the G protein with the exoglycosidase alpha-mannosidase and reduced after subsequent treatment with N-acetyl-beta-D-glucosaminidase. In concert these findings indicate that ORF IV encodes a 94-kDa N-linked glycoprotein with extensive high mannose- and/or hybrid-type oligosaccharide modifications. The presence of neutralization epitopes on the G protein and its capacity to interfere with infectivity suggest that the G protein is important for viral entry.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antigens, Viral / chemistry*
  • Antigens, Viral / genetics
  • Antigens, Viral / immunology
  • Antigens, Viral / metabolism
  • Borna disease virus / metabolism*
  • Cell Line
  • Cricetinae
  • Epitopes / immunology
  • Gene Expression
  • Genetic Vectors
  • Glycoproteins / chemistry*
  • Glycoproteins / genetics
  • Glycoproteins / immunology
  • Glycoproteins / metabolism
  • Neutralization Tests
  • Open Reading Frames
  • Rabbits
  • Rats
  • Rats, Inbred Lew
  • Semliki forest virus / genetics
  • Tumor Cells, Cultured
  • Viral Proteins / chemistry*
  • Viral Proteins / genetics
  • Viral Proteins / immunology
  • Viral Proteins / metabolism

Substances

  • Antigens, Viral
  • Epitopes
  • Glycoproteins
  • Viral Proteins