Envelope Protein Requirements for the Assembly of Infectious Virions of Porcine Reproductive and Respiratory Syndrome Virus
Open Access
- 1 October 2005
- journal article
- Published by American Society for Microbiology in Journal of Virology
- Vol. 79 (19), 12495-12506
- https://doi.org/10.1128/jvi.79.19.12495-12506.2005
Abstract
Virions of porcine reproductive and respiratory syndrome virus (PRRSV) contain six membrane proteins: the major proteins GP 5 and M and the minor proteins GP 2a , E, GP 3 , and GP 4 . Here, we studied the envelope protein requirements for PRRSV particle formation and infectivity using full-length cDNA clones in which the genes encoding the membrane proteins were disrupted by site-directed mutagenesis. By transfection of RNAs transcribed from these cDNAs into BHK-21 cells and analysis of the culture medium using ultracentrifugation, radioimmunoprecipitation, and real-time reverse transcription-PCR, we observed that the production of viral particles is dependent on both major envelope proteins; no particles were released when either the GP 5 or the M protein was absent. In contrast, particle production was not dependent on the minor envelope proteins. Remarkably, in the absence of any one of the latter proteins, the incorporation of all other minor envelope proteins was affected, indicating that these proteins interact with each other and are assembled into virions as a multimeric complex. Independent evidence for such complexes was obtained by coexpression of the minor envelope proteins in BHK-21 cells using a Semliki Forest virus expression system. By analyzing the maturation of their N-linked oligosaccharides, we found that the glycoproteins were each retained in the endoplasmic reticulum unless expressed together, in which case they were collectively transported through the Golgi complex to the plasma membrane and were even detected in the extracellular medium. As the PRRSV particles lacking the minor envelope proteins are not infectious, we hypothesize that the virion surface structures formed by these proteins function in viral entry by mediating receptor binding and/or virus-cell fusion.Keywords
This publication has 43 references indexed in Scilit:
- Construction and evaluation of genetically engineered replication-defective porcine reproductive and respiratory syndrome virus vaccine candidatesVeterinary Immunology and Immunopathology, 2004
- Rescue of disabled infectious single-cycle (DISC) Equine arteritis virus by using complementing cell lines that express minor structural glycoproteinsJournal of General Virology, 2004
- Role for Bovine Viral Diarrhea Virus E rns Glycoprotein in the Control of Activation of Beta Interferon by Double-Stranded RNAJournal of Virology, 2004
- Involvement of Sialoadhesin in Entry of Porcine Reproductive and Respiratory Syndrome Virus into Porcine Alveolar MacrophagesJournal of Virology, 2003
- Formation of Disulfide-Linked Complexes between the Three Minor Envelope Glycoproteins (GP 2b , GP 3 , and GP 4 ) of Equine Arteritis VirusJournal of Virology, 2003
- Heterodimerization of the Two Major Envelope Proteins Is Essential for Arterivirus InfectivityJournal of Virology, 2003
- Involvement of the Matrix Protein in Attachment of Porcine Reproductive and Respiratory Syndrome Virus to a Heparinlike Receptor on Porcine Alveolar MacrophagesJournal of Virology, 2002
- Porcine reproductive and respiratory syndrome virus enters cells through a low pH-dependent endocytic pathwayVirus Research, 1996
- Enhanced replication of porcine reproductive and respiratory syndrome (PRRS) virus in a homogeneous subpopulation of MA-104 cell lineArchiv für die gesamte Virusforschung, 1993
- Production of monoclonal antibodies against swine fever virus and their use in laboratory diagnosisVeterinary Microbiology, 1986