Previous Article | Next Article ![]()
Journal of Virology, June 2000, p. 5066-5074, Vol. 74, No. 11
Department of Virology II, National Institute
of Infectious Diseases, Tokyo,1 and
Third Department of Internal Medicine, Niigata University
School of Medicine, Niigata,2 Japan
Received 23 November 1999/Accepted 9 March 2000
To examine the cell fusion activity of hepatitis C virus (HCV)
envelope proteins (E1 and E2), we have established a sensitive cell
fusion assay based on the activation of a reporter gene as described
previously (O. Nussbaum, C. C. Broder, and E. A. Berger, J. Virol. 68:5411-5422, 1994). The chimeric HCV E1 and E2
proteins, each consisting of the ectodomain of the E1 and E2 envelope
protein and the transmembrane and cytoplasmic domains of the vesicular stomatitis virus G glycoprotein, were expressed on the cell surface. Cells expressing the chimeric envelope proteins and T7 RNA polymerase were cocultured with the various target cell lines transfected with a
reporter plasmid encoding the luciferase gene under the control of the
T7 promoter. After cocultivation, the cell fusion activity was
determined by the expression of luciferase in the cocultured cells. The
induction of cell fusion requires both the chimeric E1 and E2 proteins
and occurs in a low-pH-dependent manner. Although it has been shown
that HCV E2 protein binds human CD81 (P. Pileri, Y. Uematsu, S. Campagnoli, G. Galli, F. Falugi, R. Petracca, A. J. Weiner, M. Houghton, D. Rosa, G. Grandi, and S. Abrignani, Science 282:938-941,
1998), the expression of human CD81 alone is not sufficient to confer
susceptibility to cell fusion in the mouse cell line. Treatment of the
target cells with pronase, heparinase, or heparitinase reduced the cell
fusion activity induced by the chimeric envelope proteins. These
results suggest (i) that both HCV E1 and E2 proteins are responsible
for fusion with the endosomal membrane after endocytosis and (ii) that
certain protein molecules other than human CD81 and some
glycosaminoglycans on the cell surface are also involved in the cell
fusion induced by HCV.
0022-538X/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
Cell Fusion Activity of Hepatitis C Virus
Envelope Proteins
*
Corresponding author. Mailing address: Department of
Virology II, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan. Phone: 81-3-5285-1111, ext. 2521. Fax: 81-3-5285-1161. E-mail: ymatsu{at}nih.go.jp.
This article has been cited by other articles:
| J. Bacteriol. | Mol. Cell. Biol. | Microbiol. Mol. Biol. Rev. |
|---|
| Clin. Vaccine Immunol. | ALL ASM JOURNALS |
|---|