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 Cohen, L.
Right arrow Articles by Martin, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Cohen, L.
Right arrow Articles by Martin, A.

 Previous Article  |  Next Article 

Journal of Virology, August 2002, p. 7495-7505, Vol. 76, No. 15
0022-538X/02/$04.00+0     DOI: 10.1128/JVI.76.15.7495-7505.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.

Analysis of Deletion Mutants Indicates that the 2A Polypeptide of Hepatitis A Virus Participates in Virion Morphogenesis

Lisette Cohen, Danièle Bénichou, and Annette Martin*

Unité de Génétique Moléculaire des Virus Respiratoires, URA CNRS 1966, Institut Pasteur, 75724 Paris Cedex 15, France

Received 29 January 2002/ Accepted 26 April 2002

Unlike all other picornaviruses, the primary cleavage of the hepatitis A virus (HAV) polyprotein occurs at the 2A/2B junction and is carried out by the only proteinase encoded by the virus, 3Cpro. The resulting P1-2A capsid protein precursor is subsequently cleaved by 3Cpro to generate VP0, VP3, and VP1-2A, which associate as pentamers. An unidentified cellular proteinase acting at the VP1/2A junction releases the mature capsid protein VP1 from VP1-2A later in the morphogenesis process. Although these aspects of polyprotein processing are well characterized, the function of 2A is unknown. To study its role in the viral life cycle, we assessed the infectivity of synthetic, genome-length RNAs containing 11 different in-frame deletions in the 2A region. Deletions in the N-terminal 40% of 2A abolished infectivity, whereas deletions in the C-terminal 60% resulted in viruses with a small-focus replication phenotype. C-terminal deletions in 2A had no effect on RNA replication kinetics under one-step growth conditions, nor did they have an effect on capsid protein synthesis and 3Cpro-mediated processing. However, C-terminal deletions in 2A altered the VP1/2A cleavage, resulting in accumulation of uncleaved VP1-2A precursor in virions and possibly accounting for a delay in the appearance of infectious particles with these mutants, as well as a fourfold decrease in specific infectivity of the virus particles. When the capsid proteins were expressed from recombinant vaccinia viruses, the N-terminal part of 2A was required for efficient cleavage of the P1-2A precursor by 3Cpro and assembly of structural precursors into pentamers. These data indicate that the N-terminal domain of 2A must be present as a C-terminal extension of P1 for folding of the capsid protein precursor to allow efficient 3Cpro-mediated cleavages and to promote pentamer assembly, after which cleavage at the VP1/2A junction releases the mature VP1 protein, a process that appears to be necessary to produce highly infectious particles.

* Corresponding author. Mailing address: Institut Pasteur, Unité de Génétique Moléculaire des Virus Respiratoires, URA CNRS 1966, 25 Rue du Dr. Roux, 75724 Paris Cedex 15, France. Phone: 33-1-4061 3360. Fax: 33-1-4061 3045. E-mail: annettem{at}pasteur.fr.

Journal of Virology, August 2002, p. 7495-7505, Vol. 76, No. 15
0022-538X/02/$04.00+0     DOI: 10.1128/JVI.76.15.7495-7505.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Yang, Y., Yi, M., Evans, D. J., Simmonds, P., Lemon, S. M. (2008). Identification of a Conserved RNA Replication Element (cre) within the 3Dpol-Coding Sequence of Hepatoviruses. J. Virol. 82: 10118-10128 [Abstract] [Full Text]  
  • Ghibaudo, D., Cohen, L., Penin, F., Martin, A. (2004). Characterization of GB Virus B Polyprotein Processing Reveals the Existence of a Novel 13-kDa Protein with Partial Homology to Hepatitis C Virus p7 Protein. J. Biol. Chem. 279: 24965-24975 [Abstract] [Full Text]  
  • Rachow, A., Gauss-Muller, V., Probst, C. (2003). Homogenous Hepatitis A Virus Particles: PROTEOLYTIC RELEASE OF THE ASSEMBLY SIGNAL 2A FROM PROCAPSIDS BY FACTOR Xa. J. Biol. Chem. 278: 29744-29751 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»