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
Google Scholar
Right arrow Articles by Melder, D. C.
Right arrow Articles by Federspiel, M. J.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Melder, D. C.
Right arrow Articles by Federspiel, M. J.

 Previous Article  |  Next Article 

Journal of Virology, September 2009, p. 8575-8586, Vol. 83, No. 17
0022-538X/09/$08.00+0     doi:10.1128/JVI.00526-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

A Charged Second-Site Mutation in the Fusion Peptide Rescues Replication of a Mutant Avian Sarcoma and Leukosis Virus Lacking Critical Cysteine Residues Flanking the Internal Fusion Domain {triangledown}

Deborah C. Melder,1 Xueqian Yin,1 Sue E. Delos,2 and Mark J. Federspiel1*

Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota 55905,1 Department of Cell Biology, School of Medicine, University of Virginia Health System, Charlottesville, Virginia 229082

Received 13 March 2009/ Accepted 4 June 2009

The entry process of the avian sarcoma and leukosis virus (ASLV) family of retroviruses requires first a specific interaction between the viral surface (SU) glycoproteins and a receptor on the cell surface at a neutral pH, triggering conformational changes in the viral SU and transmembrane (TM) glycoproteins, followed by exposure to low pH to complete fusion. The ASLV TM glycoprotein has been proposed to adopt a structure similar to that of the Ebola virus GP2 protein: each contains an internal fusion peptide flanked by cysteine residues predicted to be in a disulfide bond. In a previous study, we concluded that the cysteines flanking the internal fusion peptide in ASLV TM are critical for efficient function of the ASLV viral glycoproteins in mediating entry. In this study, replication-competent ASLV mutant subgroup A [ASLV(A)] variants with these cysteine residues mutated were constructed and genetically selected for improved replication capacity in chicken fibroblasts. Viruses with single cysteine-to-serine mutations reverted to the wild-type sequence. However, viruses with both C9S and C45S (C9,45S) mutations retained both mutations and acquired a second-site mutation that significantly improved the infectivity of the genetically selected virus population. A charged-amino-acid second-site substitution in the TM internal fusion peptide at position 30 is preferred to rescue the C9,45S mutant ASLV(A). ASLV(A) envelope glycoproteins that contain the C9,45S and G30R mutations bind the Tva receptor at wild-type levels and have improved abilities to trigger conformational changes and to form stable TM oligomers compared to those of the C9,45S mutant glycoprotein.

* Corresponding author. Mailing address: Mayo Clinic, 200 First Street, SW, Rochester, MN 55905. Phone: (507) 284-8895. Fax: (507) 266-2122. E-mail: federspiel.mark{at}mayo.edu

{triangledown} Published ahead of print on 10 June 2009.

Journal of Virology, September 2009, p. 8575-8586, Vol. 83, No. 17
0022-538X/09/$08.00+0     doi:10.1128/JVI.00526-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





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