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 Ludwig, C.
Right arrow Articles by Wagner, R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ludwig, C.
Right arrow Articles by Wagner, R.

 Previous Article  |  Next Article 

Journal of Virology, May 2008, p. 4573-4584, Vol. 82, No. 9
0022-538X/08/$08.00+0     doi:10.1128/JVI.02353-07
Copyright © 2008, American Society for Microbiology. All Rights Reserved.

Importance of Protease Cleavage Sites within and Flanking Human Immunodeficiency Virus Type 1 Transframe Protein p6* for Spatiotemporal Regulation of Protease Activation{triangledown}

Christine Ludwig, Andreas Leiherer, and Ralf Wagner*

Institute of Medical Microbiology and Hygiene, Molecular Microbiology and Gene Therapy Unit, University of Regensburg, 93053 Regensburg, Germany

Received 31 October 2007/ Accepted 21 February 2008

The human immunodeficiency virus type 1 (HIV-1) protease (PR) has recently been shown to be inhibited by its propeptide p6* in vitro. As p6* itself is a PR substrate, the primary goal of this study was to determine the importance of p6* cleavage for HIV-1 maturation and infectivity. For that purpose, short peptide variants mimicking proposed cleavage sites within and flanking p6* were designed and analyzed for qualitative and quantitative hydrolysis in vitro. Proviral clones comprising the selected cleavage site mutations were established and analyzed for Gag and Pol processing, virus maturation, and infectivity in cultured cells. Amino-terminal cleavage site mutation caused aberrant processing of nucleocapsid proteins and delayed replication kinetics. Blocking the internal cleavage site resulted in the utilization of a flanking site at a significantly decreased hydrolysis rate in vitro, which however did not affect Gag-Pol processing and viral replication. Although mutations blocking cleavage at the p6* carboxyl terminus yielded noninfectious virions exhibiting severe Gag processing defects, mutations retarding hydrolysis of this cleavage site neither seemed to impact viral infectivity and propagation in cultured cells nor seemed to interfere with overall maturation of released viruses. Interestingly, these mutants were shown to be clearly disadvantaged when challenged with wild-type virus in a dual competition assay. In sum, we conclude that p6* cleavage is absolutely essential to allow complete activation of the PR and subsequent processing of the viral precursors.

* Corresponding author. Mailing address: Molecular Microbiology and Gene Therapy Unit, Institute of Medical Microbiology and Hygiene, University of Regensburg, 93053 Regensburg, Germany. Phone: 49 941 944 6452. Fax: 49 941 944 6484. E-mail: ralf.wagner{at}klinik.uni-regensburg.de

{triangledown} Published ahead of print on 5 March 2008.

Journal of Virology, May 2008, p. 4573-4584, Vol. 82, No. 9
0022-538X/08/$08.00+0     doi:10.1128/JVI.02353-07
Copyright © 2008, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Huang, L., Sayer, J. M., Swinford, M., Louis, J. M., Chen, C. (2009). Modulation of Human Immunodeficiency Virus Type 1 Protease Autoprocessing by Charge Properties of Surface Residue 69. J. Virol. 83: 7789-7793 [Abstract] [Full Text]  
  • Leiherer, A., Ludwig, C., Wagner, R. (2009). Uncoupling Human Immunodeficiency Virus Type 1 gag and pol Reading Frames: Role of the Transframe Protein p6* in Viral Replication. J. Virol. 83: 7210-7220 [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»