A. Vanderplasschen et al., A multipotential beta-1,6-N-acetylglucosaminyltransferase is encoded by bovine herpesvirus type 4, P NAS US, 97(11), 2000, pp. 5756-5761
Citations number
41
Categorie Soggetti
Multidisciplinary
Journal title
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
The beta-1,6-N-acetylglucosaminyltransferase (beta 1,6GnT) gene family enco
des enzymes playing crucial roles in glycan synthesis. Important changes in
beta 1,6GnT expression are observed during development, oncogenesis, and i
mmunodeficiency. The most characterized beta 1,6GnTs in this gene family ar
e the human (h) C2GnT-L and h-IGnT, which have core 2 [Gal beta 1 --> 3(Glc
NAc beta 1 --> 6)GalNAc] and 1 branching [GlcNAc beta 1 --> 3(GlcNAc beta 1
--> 6)Gal] activities, respectively. Recently, h-C2GnT-M was shown to be u
nique in forming core 2, core 4 [GlcNAc beta 1 --> 3(GlcNAc beta 1 --> 6)Ga
lNAc], and 1 structures. To date, the beta 1,6GnT gene family has been char
acterized only in mammals. Here, we describe that bovine herpesvirus type 4
(BHV-4) encodes a beta 1,6GnT expressed during viral replication and exhib
iting all of the core 2, core 4, and 1 branching activities. Sequencing of
the BHV-4 genome revealed an ORF, hereafter called BORFF3-4, encoding a pro
tein (pBORFF3-4) exhibiting 81.1%, 50.7%, and 36.6% amino acid identity wit
h h-C2GnT-M, h-C2GnT-L, and h-IGnT, respectively. Reverse transcriptase-PCR
analysis revealed that BORFF3-4 is expressed during BHV-4 replication. Exp
ression of BORFF3-4 in Chinese hamster ovary cells directed the expression
of core 2 branched oligosaccharides and 1 antigenic structures on the cell
surface. Moreover, a soluble form of pBORFF3-4 had core 4 branching activit
y in addition to core 2 and 1 branching activities. Finally, infection of a
C2GnT-negative cell line with BHV-4 induced expression of core 2 branched
oligosaccharides. This study extends the beta 1,6GnT gene family to a viral
gene and provides a model to study the biological functions of a beta 1,6G
nT in the context of viral infection.