Glycosylation modulates arenavirus glycoprotein expression and function.
The glycoprotein of lymphocytic choriomeningitis virus (LCMV) contains nine potential N-linked glycosylation sites. We investigated the function of these N-glycosylations by using alanine-scanning mutagenesis. All the available sites were occupied on GP1 and two of three on GP2. N-linked glycan mutations at positions 87 and 97 on GP1 resulted in reduction of expression and absence of cleavage and were necessary for downstream functions, as confirmed by the loss of GP-mediated fusion activity with T87A and S97A mutants. In contrast, T234A and E379N/A381T mutants impaired GP-mediated cell fusion without altered expression or processing. Infectivity via virus-like particles required glycans and a cleaved glycoprotein. Glycosylation at the first site within GP2, not normally utilized by LCMV, exhibited increased VLP infectivity. We also confirmed the role of the N-linked glycan at position 173 in the masking of the neutralizing epitope GP-1D. Taken together, our results indicated a strong relationship between fusion and infectivity.
University of California, Irvine, Department of Molecular Biology and Biochemistry & Division of Infectious Disease, 3205 McGaugh Hall, Irvine, CA 92697-3900, USA. cbonhomm@uci.edu
Cyrille J
CJ
Bonhomme
Althea A
AA
Capul
Elvin J
EJ
Lauron
Lydia H
LH
Bederka
Kristeene A
KA
Knopp
Michael J
MJ
Buchmeier
D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D000956:Antigens, Viral / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D006031:Glycosylation; D006801:Humans; D008217:Lymphocytic choriomeningitis virus / Q000235:genetics / Q000502:physiology*; D016297:Mutagenesis, Site-Directed; D011499:Protein Processing, Post-Translational; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D053586:Virus Internalization
D000956:Antigens, Viral; D006023:Glycoproteins; D014764:Viral Proteins; C115679:glycoprotein peptide, Lymphocytic choriomeningitis virus