JVI Figure table search 04
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Zafrullah, M.
Right arrow Articles by Jameel, S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Zafrullah, M.
Right arrow Articles by Jameel, S.

 Previous Article  |  Next Article 

Journal of Virology, May 1999, p. 4074-4082, Vol. 73, No. 5
0022-538X/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.

Mutational Analysis of Glycosylation, Membrane Translocation, and Cell Surface Expression of the Hepatitis E Virus ORF2 Protein

Mohammad Zafrullah,1 Mehmet Hakan Ozdener,1,dagger Ravinder Kumar,1 Subrat Kumar Panda,2 and Shahid Jameel1,*

Virology Group, International Centre for Genetic Engineering and Biotechnology,1 and Department of Pathology, All India Institute of Medical Sciences,2 New Delhi, India

Received 1 June 1998/Accepted 12 January 1999

Hepatitis E virus (HEV) is the etiological agent for viral hepatitis type E, which is a major problem in the developing world. Because HEV cannot be cultured in vitro, very little information exists on the mechanisms of HEV gene expression and genome replication. HEV is a positive-strand RNA virus with three potential open reading frames (ORFs), one of which (ORF2) is postulated to encode the major viral capsid protein (pORF2). We earlier showed (S. Jameel, M. Zafrullah, M. H. Ozdener, and S. K. Panda, J. Virol. 70:207-216, 1996) pORF2 to be a ~88-kDa glycoprotein, carrying N-linked glycans and a potential endoplasmic reticulum (ER)-directing signal at its N terminus. Treatment with the drugs brefeldin A and monensin suggest that the protein may accumulate within the ER. Based on mutational analysis, we demonstrate Asn-310 to be the major site of N-glycan addition. In COS-1 cell expression and in vitro translation experiments, we confirm the ER-translocating nature of the pORF2 N-terminal hydrophobic sequence and show that the protein is cotranslationally, but not posttranslationally, translocated across the ER membrane. Earlier, we had also demonstrated cell surface localization of a fraction of the COS-1 cell-expressed pORF2. Using glycosylation- and translocation-defective mutants of pORF2, we now show that while transit of pORF2 into the ER is necessary for its cell surface expression, glycosylation of the protein is not required for such localization. These results may offer clues to the mechanisms of gene expression and capsid assembly in HEV.

* Corresponding author. Mailing address: International Centre for Genetic Engineering and Biotechnology, P.O. Box 10504, Aruna Asaf Ali Marg, New Delhi 110067, India. Phone: 91-11-6176680. Fax: 91-11-6162316. E-mail: shahid{at}icgeb.res.in.

dagger Present address: Department of Medicine, Division of Clinical Pharmacology, Thomas Jefferson University School of Medicine, Philadelphia, PA.

Journal of Virology, May 1999, p. 4074-4082, Vol. 73, No. 5
0022-538X/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.


This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. Mol. Cell. Biol. Microbiol. Mol. Biol. Rev.
Clin. Vaccine Immunol. ALL ASM JOURNALS

Copyright © 1999 by the American Society for Microbiology. All rights reserved.