HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Hui, E. K.-W. Articles by Lo, S. J. Search for Related Content PubMed PubMed Citation Articles by Hui, E. K.-W. Articles by Lo, S. J. Agricola Articles by Hui, E. K.-W. Articles by Lo, S. J.

Hepatitis B viral core proteins with an N-terminal extension can assemble into core-like particles but cannot be enveloped

Institute of Microbiology and Immunology, School of Life Science, National Yang-Ming University, Taipei, Taiwan 112, Republic of China ¹

Author for correspondence: Szecheng J. Lo.Fax +886 2 2821 2880. e-mail losj{at}ym.edu.tw

The structure of hepatitis B virus (HBV) nucleocapsids has been revealed in great detail by cryoelectron microscopy. How nucleocapsids interact with surface antigens to form enveloped virions remains unknown. In this study, core mutants with N-terminal additions were created to address two questions: (1) can these mutant core proteins still form nucleocapsids and (2) if so, can the mutant nucleocapsids interact with surface antigens to form virion-like particles. One plasmid encoding an extra stretch of 23 aa, including six histidine residues, fused to the N terminus of the core protein (designated HisC183) was expressed in Escherichia coli and detected by Western blot. CsCl gradient and electron microscopy analyses indicated that HisC183 could self-assemble into nucleocapsids. When HisC183 or another similar N-terminal fusion core protein (designated FlagC183) was co-expressed with a core-negative plasmid in human hepatoma cells, both mutant core proteins self-assembled into nucleocapsids. These particles also retained kinase activity. Using an endogenous polymerase assay, a fill-in HBV DNA labelled with isotope was obtained from intracellular nucleocapsids formed by mutant cores. In contrast, no such signal was detected from the transfection medium, which was consistent with PCR and Southern blot analyses. Results indicate that core mutants with N-terminal extensions can form nucleocapsids, but are blocked during the envelopment process and cannot form secreted virions. The mutant nucleocapsids generated from this work should facilitate further study on how nucleocapsids interact with surface antigens.

This article has been cited by other articles:

				K. Li, F. Zoulim, C. Pichoud, K. Kwei, S. Villet, J. Wands, J. Li, and S. Tong Critical Role of the 36-Nucleotide Insertion in Hepatitis B Virus Genotype G in Core Protein Expression, Genome Replication, and Virion Secretion J. Virol., September 1, 2007; 81(17): 9202 - 9215. [Abstract] [Full Text] [PDF]

				X. Lu, T. Tran, E. Simsek, and T. M. Block The Alkylated Imino Sugar, n-(n-Nonyl)-Deoxygalactonojirimycin, Reduces the Amount of Hepatitis B Virus Nucleocapsid in Tissue Culture J. Virol., November 15, 2003; 77(22): 11933 - 11940. [Abstract] [Full Text] [PDF]

				S. Le Pogam, T. T.-T. Yuan, G. K. Sahu, S. Chatterjee, and C. Shih Low-Level Secretion of Human Hepatitis B Virus Virions Caused by Two Independent, Naturally Occurring Mutations (P5T and L60V) in the Capsid Protein J. Virol., October 1, 2000; 74(19): 9099 - 9105. [Abstract] [Full Text]

				C. Hourioux, A. Touzé, P. Coursaget, and P. Roingeard DNA-containing and empty hepatitis B virus core particles bind similarly to envelope protein domains J. Gen. Virol., April 1, 2000; 81(4): 1099 - 1101. [Abstract] [Full Text]