Previous Article | Next Article ![]()
Journal of Virology, December 1998, p. 9459-9469, Vol. 72, No. 12
Department of Molecular Biology, University
of Wyoming, Laramie, Wyoming 82071-3944
Received 24 April 1998/Accepted 10 September 1998
gp64 is the major envelope glycoprotein in the budded form of
Autographa californica multicapsid nucleopolyhedrovirus
(AcMNPV). gp64 is essential for AcMNPV
infection, as it mediates penetration of budded virus into host cells
via the endocytic pathway. In this study, we used site-directed
mutagenesis to map the positions of the N-linked glycans on
AcMNPV gp64, characterize their structures, and evaluate
their influence on gp64 function. We found that four of the five
consensus N-glycosylation sites in gp64 are used, and we mapped the
positions of those sites to amino acids 198, 355, 385, and 426 in the
polypeptide chain. Endoglycosidase H sensitivity assays showed that
N-linked glycans located at different positions are processed to
various degrees. Lectin blotting analyses showed that each N-linked
glycan on gp64 contains
0022-538X/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
Mutational Analysis of the N-Linked Glycans on
Autographa californica Nucleopolyhedrovirus gp64
and
-linked mannose, all but one contains
-linked fucose, and none contains detectable
-linked galactose or
2,6-linked sialic acid. The amounts of infectious progeny produced
by AcMNPV mutants lacking one, two, or three N-linked
glycans on gp64 were about 10- to 100-fold lower than wild-type levels.
This reduction did not correlate with reductions in the expression,
transport, or inherent fusogenic activity of the mutant gp64s or in the
gp64 content of mutant budded virus particles. However, all of the
mutant viruses bound more slowly than the wild type. Therefore,
elimination of one or more N-glycosylation sites in AcMNPV
gp64 impairs binding of budded virus to the cell, which explains why
viruses containing these mutant forms of gp64 produce less infectious progeny.
*
Corresponding author. Mailing address: Department of
Molecular Biology, University of Wyoming, Laramie, WY 82071-3944. Phone: (307) 766-4282 or (307) 766-3435. Fax: (307) 766-5098. E-mail: dljarvis{at}uwyo.edu.
Present address: Department of Plant Pathology, Texas A&M
University, College Station, TX 77843-2132.
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»