Previous Article | Next Article ![]()
J. Virol., 06 1996, 3815-3822, Vol 70, No. 6
AV Nicola, SH Willis, NN Naidoo, RJ Eisenberg and GH Cohen
Glycoprotein D (gD) of herpes simplex virus (HSV) is essential for virus
entry. Truncated forms of gD lacking the transmembrane and cytoplasmic tail
regions have been shown to bind to cells and block plaque formation. Using
complementation analysis and a panel of gD mutants, we previously
identified four regions of gD (regions I to IV) which are important for
virus entry. Here, we used baculovirus vectors to overexpress truncated
forms of wild-type gD from HSV type 1 (HSV-1) [gD-1(306t)] and HSV-2
[gD-2(306t)] and four mutants, gD-1(inverted delta 34t), gD-1(inverted
delta 126t), gD-1(inverted delta 243t), and gD-1(delta 290-299t), each
having a mutation in one of the four functional regions. We used an
enzyme-linked immunosorbent assay and circular dichroism to analyze the
structure of these proteins, and we used functional assays to study the
role of gD in binding, penetration, and cell-to-cell spread. gD-1 and gD-2
are similar in antigenic structure and thermal stability but vary in
secondary structure. Mutant proteins with insertions in region I or II were
most altered in structure and stability, while mutants with insertions in
region III or IV were less altered. gD-1(306t) and gD-2(306t) inhibited
both plaque formation and cell-to-cell transmission of HSV-1. In spite of
obvious structural differences, all of the mutant proteins bound to cells,
confirming that binding is not the only function of gD. The region I mutant
did not inhibit HSV plaque formation or cell-to-cell spread, suggesting
that this region is necessary for the function of gD in these processes.
Surprisingly, the other three mutant proteins functioned in all of the in
vitro assays, indicating that the ability of gD to bind to cells and
inhibit infection does not correlate with its ability to initiate infection
as measured by the complementation assay. The region IV mutant, gD-1(delta
290-299t), had an unexpected enhanced inhibitory effect on HSV infection.
Taken together, the results argue against a single functional domain in gD.
It is likely that different gD structural elements are involved in
successive steps of infection.
Copyright © 1996, American Society for Microbiology
Structure-function analysis of soluble forms of herpes simplex virus glycoprotein D
Department of Microbiology, School of Dental Medicine, University of Pennsylvania, Philadelphia 19104, USA. anicola@biochem.dental.upenn.edu
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»