JVI Figure table search 04
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
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 Bouloy, M.
Right arrow Articles by Haller, O.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Bouloy, M.
Right arrow Articles by Haller, O.

Journal of Virology, February 2001, p. 1371-1377, Vol. 75, No. 3
0022-538X/01/$04.00+0   DOI: 10.1128/JVI.75.3.1371-1377.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.

Genetic Evidence for an Interferon-Antagonistic Function of Rift Valley Fever Virus Nonstructural Protein NSs

Michèle Bouloy,1 Christian Janzen,2,dagger Pierre Vialat,1 Huot Khun,3 Jovan Pavlovic,4 Michel Huerre,3 and Otto Haller2,*

Groupe des Bunyaviridés1 and Unité d'Histopathologie,3 Institut Pasteur, F-75724 Paris Cedex, France; Institute of Medical Virology, University of Zürich, CH-8028 Zürich, Switzerland4; and Abteilung Virologie, Institut für Medizinische Mikrobiologie und Hygiene, Universität Freiburg, D-79008 Freiburg, Germany2

Received 21 August 2000/Accepted 3 November 2000

Rift Valley fever virus (RVFV), a phlebovirus of the family Bunyaviridae, is a major public health threat in Egypt and sub-Saharan Africa. The viral and host cellular factors that contribute to RVFV virulence and pathogenicity are still poorly understood. All pathogenic RVFV strains direct the synthesis of a nonstructural phosphoprotein (NSs) that is encoded by the smallest (S) segment of the tripartite genome and has an undefined accessory function. In this report, we show that MP12 and clone 13, two attenuated RVFV strains with mutations in the NSs gene, were highly virulent in IFNAR-/- mice lacking the alpha/beta interferon (IFN-alpha /beta ) receptor but remained attenuated in IFN-gamma receptor-deficient mice. Both attenuated strains proved to be excellent inducers of early IFN-alpha /beta production. In contrast, the virulent strain ZH548 failed to induce detectable amounts of IFN-alpha /beta and replicated extensively in both IFN-competent and IFN-deficient mice. Clone 13 has a defective NSs gene with a large in-frame deletion. This defect in the NSs gene results in expression of a truncated protein which is rapidly degraded. To investigate whether the presence of the wild-type NSs gene correlated with inhibition of IFN-alpha /beta production, we infected susceptible IFNAR-/- mice with S gene reassortant viruses. When the S segment of ZH548 was replaced by that of clone 13, the resulting reassortants became strong IFN inducers. When the defective S segment of clone 13 was exchanged with the wild-type S segment of ZH548, the reassortant virus lost the capacity to stimulate IFN-alpha /beta production. These results demonstrate that the ability of RVFV to inhibit IFN-alpha /beta production correlates with viral virulence and suggest that the accessory protein NSs is an IFN antagonist.

* Corresponding author. Mailing address: Abteilung Virologie, Institut für Medizinische Mikrobiologie und Hygiene, Universität Freiburg, D-79008 Freiburg, Germany. Phone: 49-761-2036534. Fax: 49-761-2036626. E-mail: HALLER{at}UKL.UNI-FREIBURG.DE.

dagger Present address: The Rockefeller University, New York, NY 10021.

Journal of Virology, February 2001, p. 1371-1377, Vol. 75, No. 3
0022-538X/01/$04.00+0   DOI: 10.1128/JVI.75.3.1371-1377.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.


This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. Mol. Cell. Biol. Microbiol. Mol. Biol. Rev.
Clin. Vaccine Immunol. ALL ASM JOURNALS

Copyright © 2001 by the American Society for Microbiology. All rights reserved.