The core 2 beta-1,6-N-acetylglucosaminyltransferase-M encoded by bovine herpesvirus 4 is not essential for virus replication despite contributing to post-translational modifications of structural proteins.
The Bo17 gene of bovine herpesvirus 4 (BoHV-4) is the only virus gene known to date that encodes a homologue of the cellular core 2 beta-1,6-N-acetylglucosaminyltransferase-mucine type (C2GnT-M). Recently, our phylogenetic study revealed that the Bo17 gene has been acquired from an ancestor of the African buffalo around 1.5 million years ago. Despite this recent origin, the Bo17 sequence has spread to fixation in the virus population possibly by natural selection. Supporting the latter hypothesis, it has been shown by our group for the V. test strain that Bo17 is expressed during BoHV-4 replication in vitro, and that Bo17 expression product (pBo17) has all three enzymic activities exhibited by cellular C2GnT-M, i.e. core 2, core 4 and I branching activities. In the present study, firstly it was investigated whether encoding a functional C2GnT-M is a general property of BoHV-4 strains. Analysis of nine representative strains of the BoHV-4 species revealed that all of them express the Bo17 gene and the associated core 2 branching activity during virus replication in vitro. Secondly, in order to investigate the roles of Bo17, its kinetic class of expression was analysed and a deleted recombinant strain was produced. These experiments revealed that Bo17 is expressed as an early gene which is not essential for virus replication in vitro. However, comparison of the structural proteins, produced by the wild-type, the revertant and the deleted viruses, by 2D gels demonstrated that pBo17 contributes to the post-translational modifications of structural proteins. Possible roles of Bo17 in vivo are discussed.
Markine-Goriaynoff
Nicolas
N
Immunology-Vaccinology (B43b), Department of Infectious and Parasitic Diseases, Faculty of Veterinary Medicine, University of Liège, B-4000 Liège, Belgium.
Gillet
Laurent
L
Immunology-Vaccinology (B43b), Department of Infectious and Parasitic Diseases, Faculty of Veterinary Medicine, University of Liège, B-4000 Liège, Belgium.
Karlsen
Odd A
OA
Department of Molecular Biology, The Gade Institute, University of Bergen, 5020 Bergen, Norway.
Haarr
Lars
L
Department of Microbiology and Immunology, The Gade Institute, University of Bergen, 5020 Bergen, Norway.
Minner
Frédéric
F
Immunology-Vaccinology (B43b), Department of Infectious and Parasitic Diseases, Faculty of Veterinary Medicine, University of Liège, B-4000 Liège, Belgium.
Pastoret
Paul-Pierre
PP
Compton Laboratory, Institute for Animal Health, Compton, Newbury, Berkshire RG20 7NN, UK.
Fukuda
Minoru
M
The Burnham Institute, 10901 North Torrey Pines Rd, La Jolla, CA 92037, USA.
Vanderplasschen
Alain
A
Immunology-Vaccinology (B43b), Department of Infectious and Parasitic Diseases, Faculty of Veterinary Medicine, University of Liège, B-4000 Liège, Belgium.
D004790:Enzyme Induction; D017353:Gene Deletion; D015870:Gene Expression; D026021:Herpesvirus 4, Bovine / Q000235:genetics / Q000378:metabolism*; D017351:N-Acetylglucosaminyltransferases / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D013045:Species Specificity; D015678:Viral Structural Proteins / Q000378:metabolism*; D014779:Virus Replication
D015678:Viral Structural Proteins; D017351:N-Acetylglucosaminyltransferases