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Title: Enzymatic treatment of duck hepatitis B virus: Topology of the surface proteins for virions and noninfectious subviral particles

Abstract

The large surface antigen L of duck hepatitis B virus exhibits a mixed topology with the preS domains of the protein alternatively exposed to the particles' interior or exterior. After separating virions from subviral particles (SVPs), we compared their L topologies and showed that both particle types exhibit the same amount of L with the following differences: 1-preS of intact virions was enzymatically digested with chymotrypsin, whereas in SVPs only half of preS was accessible, 2-phosphorylation of L at S118 was completely removed by phosphatase treatment only in virions, 3-iodine-125 labeling disclosed a higher ratio of exposed preS to S domains in virions compared to SVPs. These data point towards different surface architectures of virions and SVPs. Because the preS domain acts in binding to a cellular receptor of hepatocytes, our findings implicate the exclusion of SVPs as competitors for the receptor binding and entry of virions.

Authors:
 [1];  [1];  [2]
  1. Heinrich-Pette-Institut fuer Experimentelle Virologie und Immunologie an der Universitaet Hamburg, Martinistrasse 52, D-20251 Hamburg (Germany)
  2. Heinrich-Pette-Institut fuer Experimentelle Virologie und Immunologie an der Universitaet Hamburg, Martinistrasse 52, D-20251 Hamburg (Germany). E-mail: mbruns@hpi.uni-hamburg.de
Publication Date:
OSTI Identifier:
20976995
Resource Type:
Journal Article
Resource Relation:
Journal Name: Virology; Journal Volume: 359; Journal Issue: 1; Other Information: DOI: 10.1016/j.virol.2006.09.006; PII: S0042-6822(06)00651-9; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; ANTIGENS; CHYMOTRYPSIN; DUCKS; HEPATITIS; IODINE 125; LABELLING; LIVER CELLS; PHOSPHORYLATION; RECEPTORS; TOPOLOGY; VIRUSES

Citation Formats

Franke, Claudia, Matschl, Urte, and Bruns, Michael. Enzymatic treatment of duck hepatitis B virus: Topology of the surface proteins for virions and noninfectious subviral particles. United States: N. p., 2007. Web. doi:10.1016/j.virol.2006.09.006.
Franke, Claudia, Matschl, Urte, & Bruns, Michael. Enzymatic treatment of duck hepatitis B virus: Topology of the surface proteins for virions and noninfectious subviral particles. United States. doi:10.1016/j.virol.2006.09.006.
Franke, Claudia, Matschl, Urte, and Bruns, Michael. Thu . "Enzymatic treatment of duck hepatitis B virus: Topology of the surface proteins for virions and noninfectious subviral particles". United States. doi:10.1016/j.virol.2006.09.006.
@article{osti_20976995,
title = {Enzymatic treatment of duck hepatitis B virus: Topology of the surface proteins for virions and noninfectious subviral particles},
author = {Franke, Claudia and Matschl, Urte and Bruns, Michael},
abstractNote = {The large surface antigen L of duck hepatitis B virus exhibits a mixed topology with the preS domains of the protein alternatively exposed to the particles' interior or exterior. After separating virions from subviral particles (SVPs), we compared their L topologies and showed that both particle types exhibit the same amount of L with the following differences: 1-preS of intact virions was enzymatically digested with chymotrypsin, whereas in SVPs only half of preS was accessible, 2-phosphorylation of L at S118 was completely removed by phosphatase treatment only in virions, 3-iodine-125 labeling disclosed a higher ratio of exposed preS to S domains in virions compared to SVPs. These data point towards different surface architectures of virions and SVPs. Because the preS domain acts in binding to a cellular receptor of hepatocytes, our findings implicate the exclusion of SVPs as competitors for the receptor binding and entry of virions.},
doi = {10.1016/j.virol.2006.09.006},
journal = {Virology},
number = 1,
volume = 359,
place = {United States},
year = {Thu Mar 01 00:00:00 EST 2007},
month = {Thu Mar 01 00:00:00 EST 2007}
}
  • Recent studies suggest that hepatitis B virus (HBV), despite being a DNA virus, replicates via an RNA intermediate. The HBV life cycle is therefore a permuted version of the RNA retroviral life cycle. Sequence homology between retroviral reverse transcriptase and the putative HBV polymerase gene product suggests the presence of an HBV reverse transcriptase. As yet, there has been no direct evidence that reverse transcriptase activity is present in the viral particle. The authors used activity gel analysis to detect the in situ catalytic activities of DNA polymerases after sodium dodecyl sulfate-polyacrylamide gel electrophorsis. These studies demonstrated that HBV-like particlesmore » secreted by a differentiated human hepatoma cell line tranfected with genomic HBV DNA contain two major polymerase activities which migrate as {approximately}90- and {approximately}70-kilodalton (kDa) proteins. This demonstrated, for the first time, that HBV-like particles contain a novel DNA polymerase-reverse transcriptase activity. Furthermore, they propose that the 70-kDa reverse transcriptase may be produced by proteolytic self-cleavage of the 90-kDa precursor protein.« less
  • The authors examined the transcription of the hepatitis B virus surface antigen (HBsAg) gene in COs cells transfected with simian virus 40-based recombinant plasmids. When positioned behind the simian virus 40 late promoter, three transcripts were identified which hybridized to the HBsAg gene: a 2,000-nucleotide transcript colinear with a gene, a 1,100-nucleotide transcript representing a spliced molecule in which a major portion of the sequences encoding HBsAg were deleted, and an 800-nucleotide transcript derived primarily from sequences 3' to the HBsAg gene. The splice acceptor site utilized by the 1,100-nucleotide transcript is located immediately upstream of an open reading framemore » of unknown function contained within the 3' nontranslated region of the HBsAg gene. The HBsAg-specific mRNA species terminate 12 to 19 base pairs 3' of the sequence UAUAAA, similar to the concensus hexanucleotide which is thought to promote polyadenylation (AAUAAA). They constructed a series of plasmids with progressive deletions from the region surrounding where these transcripts terminate. Analysis of mRNA produced by cells transfected with these plasmids indicated that the signal hexanucleotide is in itself unable to promote the efficient processing of mRNA in the absence of downstream hepatitis B virus sequences. Processing proceeds properly, however, from plasmids containing an additional 30 nucleotides 3' of this signal.« less
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