Open reading frame III of borna disease virus encodes a nonglycosylated matrix protein.
The open reading frame III of Borna disease virus (BDV) codes for a protein with a mass of 16 kDa, named p16 or BDV-M. p16 was described as an N-glycosylated protein in several previous publications and therefore was termed gp18, although the amino acid sequence of p16 does not contain any regular consensus sequence for N glycosylation. We examined glycosylation of p16 and studied its membrane topology using antisera raised against peptides, which comprise the N and the C termini. Neither an N- nor a C-terminal peptide is cleaved from p16 during maturation. Neither deglycosylation of p16 by endoglycosidases nor binding of lectin to p16 was detectable. Introduction of typical N-glycosylation sites at the proposed sites of p16 failed in carbohydrate attachment. Flotation experiments with membranes of BDV-infected cells on density gradients revealed that p16 is not an integral membrane protein, since it can be dissociated from membranes. Our experimental data strongly suggest that p16 is a typical nonglycosylated matrix protein associated at the inner surface of the viral membrane, as is true for homologous proteins of other members of the Mononegavirales order.
Kraus
I
I
Institut für Virologie, Philipps-Universität Marburg, D-35037 Marburg, Germany.
Eickmann
M
M
Kiermayer
S
S
Scheffczik
H
H
Fluess
M
M
Richt
J A
JA
Garten
W
W
D001287:Attachment Sites, Microbiological; D001891:Borna disease virus / Q000737:chemistry / Q000235:genetics*; D002241:Carbohydrates / Q000032:analysis; D002462:Cell Membrane / Q000737:chemistry; D006031:Glycosylation; D057927:Hydrophobic and Hydrophilic Interactions; D016366:Open Reading Frames; D014763:Viral Matrix Proteins / Q000032:analysis* / Q000737:chemistry / Q000235:genetics
D002241:Carbohydrates; D014763:Viral Matrix Proteins