title: Different point mutations within the conserved N-glycosylation motif of pseudorabies virus glycoprotein M result in expression of a nonglycosylated form of the protein.
abstract: Glycoprotein M (gM) constitutes one of the rare examples of a nonessential glycoprotein conserved throughout all herpesvirus subfamilies. Whereas gM in wild-type pseudorabies virus (PrV) strains carries an N-glycan, gM of the attenuated strain Bartha is not glycosylated due to a point mutation in the N-glycosylation motif. Since PrV Bartha lacks glycoproteins E and I and carries a mutated gC, we analysed glycosylation of gM in isogenic PrV glycoprotein deletion mutants. Whereas gM was glycosylated normally in most mutants, two independent gC deletion mutants and a gI mutant expressed a nonglycosylated form of gM. DNA sequence analyses revealed the presence of point mutations in the N-glycosylation consensus motif. Surprisingly, mutations in strain Bartha, the two gC-deletion mutants and the gI mutant proved to be different, although all affected the N-glycosylation motif. Thus, our data show that different, apparently independent point mutations cause expression of nonglycosylated gM.
authors.affiliation: Institute of Molecular and Cellular Virology, Friedrich-Loeffler-Institutes, Federal Research Centre for Virus Diseases of Animals, Insel Riems, Germany.
authors.forename: J M
authors.initials: JM
authors.lastname: Dijkstra
authors.forename: A
authors.initials: A
authors.lastname: Brack
authors.forename: A
authors.initials: A
authors.lastname: Jöns
authors.forename: B G
authors.initials: BG
authors.lastname: Klupp
authors.forename: T C
authors.initials: TC
authors.lastname: Mettenleiter
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002460:Cell Line; D017124:Conserved Sequence; D004279:DNA, Viral / Q000235:genetics; D015870:Gene Expression; D005814:Genes, Viral; D006031:Glycosylation; D011558:Herpesvirus 1, Suid / Q000235:genetics*; D008969:Molecular Sequence Data; D017354:Point Mutation; D011817:Rabbits; D014759:Viral Envelope Proteins / Q000737:chemistry* / Q000235:genetics*
chemical_list: D004279:DNA, Viral; D014759:Viral Envelope Proteins; C042966:pseudorabies virus glycoproteins