This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Alejo, A. Articles by Salas, M. L. Search for Related Content PubMed PubMed Citation Articles by Alejo, A. Articles by Salas, M. L.

African Swine Fever Virus Proteinase Is Essential for Core Maturation and Infectivity

Centro de Biología Molecular "Severo Ochoa" (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain

Received 4 November 2002/ Accepted 12 February 2003

African swine fever virus (ASFV) encodes two polyprotein precursors named pp220 and pp62 that are sequentially processed during viral infection, giving rise to six major structural proteins. These reside at the core shell, a matrix domain located between the endoplasmic reticulum-derived inner envelope and the DNA-containing nucleoid. Proteolytic processing of the polyprotein precursors is catalyzed by the viral proteinase pS273R, a cysteine proteinase that shares sequence similarity with the SUMO1-processing peptidases. We describe here the construction and characterization of an ASFV recombinant, vS273Ri, that inducibly expresses the ASFV proteinase. Using vS273Ri, we show that repression of proteinase expression inhibits polyprotein processing and strongly impairs infective virus production. Electron microscopic examination of vS273Ri-infected cells showed that inhibition of proteolytic processing leads to the assembly of defective icosahedral particles containing a noncentered electron-dense nucleoid surrounded by an abnormal core shell of irregular thickness. The analysis of purified extracellular defective particles revealed that they contain the unprocessed pp220 and pp62 precursors, as well as the major DNA-binding nucleoid proteins p10 and pA104R. Altogether, these results indicate that the proteolytic processing of the polyproteins is not required for their incorporation into the assembling particles nor for the incorporation of the DNA-containing nucleoid. Instead, the ASFV proteinase is involved in a late maturational step that is essential for proper core assembly and infectivity.

This article has been cited by other articles:

• Epifano, C., Krijnse-Locker, J., Salas, M. L., Rodriguez, J. M., Salas, J. (2006). The African Swine Fever Virus Nonstructural Protein pB602L Is Required for Formation of the Icosahedral Capsid of the Virus Particle. J. Virol. 80: 12260-12270 [Abstract] [Full Text]  
• Epifano, C., Krijnse-Locker, J., Salas, M. L., Salas, J., Rodriguez, J. M. (2006). Generation of Filamentous Instead of Icosahedral Particles by Repression of African Swine Fever Virus Structural Protein pB438L. J. Virol. 80: 11456-11466 [Abstract] [Full Text]  
• Rodriguez, I., Redrejo-Rodriguez, M., Rodriguez, J. M., Alejo, A., Salas, J., Salas, M. L. (2006). African Swine Fever Virus pB119L Protein Is a Flavin Adenine Dinucleotide-Linked Sulfhydryl Oxidase.. J. Virol. 80: 3157-3166 [Abstract] [Full Text]  
• Majeau, N., Gagne, V., Bolduc, M., Leclerc, D. (2005). Signal peptide peptidase promotes the formation of hepatitis C virus non-enveloped particles and is captured on the viral membrane during assembly. J. Gen. Virol. 86: 3055-3064 [Abstract] [Full Text]  
• Eulalio, A., Nunes-Correia, I., Carvalho, A. L., Faro, C., Citovsky, V., Simoes, S., Pedroso de Lima, M. C. (2004). Two African Swine Fever Virus Proteins Derived from a Common Precursor Exhibit Different Nucleocytoplasmic Transport Activities. J. Virol. 78: 9731-9739 [Abstract] [Full Text]  
• Rodriguez, J. M., Garcia-Escudero, R., Salas, M. L., Andres, G. (2004). African Swine Fever Virus Structural Protein p54 Is Essential for the Recruitment of Envelope Precursors to Assembly Sites. J. Virol. 78: 4299-4313 [Abstract] [Full Text]