Submitted to: Journal of Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2001
Publication Date: N/A
Citation: Interpretive Summary: Borna disease (BD) is a sporadically occurring, usually fatal polioencephalomyelitis that primarily affects horses and sheep. More rarely, a range of other domestic and zoo species and possibly humans are affected. The etiological agent of BD, the Borna Disease Virus (BDV), is an enveloped virus characterized by a non-segmented negative strand RNA genome ethat belongs to the new family Bornaviridae within the order Mononegavirales. As part of our ongoing studies on the function of BDV-specific proteins we examined the open reading frame (ORF) III of BDV which codes for a protein with a mass of 16 kilodalton, named BDV matrixprotein (BDV-M). We examined the biochemical properties of BDV-M and found that it is a typical non-glycosylated matrix protein associated with the inner surface of the viral membrane, as is true for homologous proteins of other members of the Mononegavirales order. Our work on biochemical properties of BDV-proteins will lead to a better understanding of virus replication and virus transmission. This knowledge will help us to target areas for prophylactic intervention and treatment.
Technical Abstract: 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.