HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by van Aken, D. Articles by Snijder, E. J. Search for Related Content PubMed PubMed Citation Articles by van Aken, D. Articles by Snijder, E. J. Agricola Articles by van Aken, D. Articles by Snijder, E. J.

Proteolytic maturation of replicase polyprotein pp1a by the nsp4 main proteinase is essential for equine arteritis virus replication and includes internal cleavage of nsp7

Molecular Virology Laboratory, Department of Medical Microbiology, Leiden University Medical Center, LUMC E4-P, PO Box 9600, 2300 RC Leiden, The Netherlands

Correspondence
Eric J. Snijder
e.j.snijder{at}lumc.nl

The positive-stranded RNA genome of the arterivirus Equine arteritis virus (order Nidovirales) encodes the partially overlapping replicase polyproteins pp1a (1727 aa) and pp1ab (3175 aa). Previously, three viral proteinases were reported to cleave these large polyproteins into 12 non-structural proteins (nsps). The chymotrypsin-like viral main proteinase residing in nsp4 is responsible for eight of these cleavages. Processing of the C-terminal half of pp1a (the nsp3–8 region) was postulated to occur following either of two alternative proteolytic pathways (the ‘major’ and ‘minor’ pathways). Here, the importance of these two pathways was investigated by using a reverse-genetics system and inactivating each of the cleavage sites by site-directed mutagenesis. For all of these pp1a cleavage sites, mutations that prevented cleavage by the nsp4 proteinase were found to block or severely inhibit EAV RNA synthesis. Furthermore, our studies identified a novel nsp4 cleavage site (Glu-1575/Ala-1576) that is located within nsp7 and is conserved in arteriviruses. The N-terminal nsp7 fragment (nsp7) derived from this cleavage was detected in lysates of both EAV-infected cells and cells transiently expressing pp1a. Mutagenesis of the novel cleavage site in the context of an EAV full-length cDNA clone proved to be lethal, underlining the fact that the highly regulated, nsp4-mediated processing of the C-terminal half of pp1a is a crucial event in the arterivirus life cycle.

Published online ahead of print on 26 September 2006 as DOI 10.1099/vir.0.82269-0.

This article has been cited by other articles:

				Y. Sun, F. Xue, Y. Guo, M. Ma, N. Hao, X. C. Zhang, Z. Lou, X. Li, and Z. Rao Crystal Structure of Porcine Reproductive and Respiratory Syndrome Virus Leader Protease Nsp1{alpha} J. Virol., November 1, 2009; 83(21): 10931 - 10940. [Abstract] [Full Text] [PDF]

				J. Han, M. S. Rutherford, and K. S. Faaberg The Porcine Reproductive and Respiratory Syndrome Virus nsp2 Cysteine Protease Domain Possesses both trans- and cis-Cleavage Activities J. Virol., September 15, 2009; 83(18): 9449 - 9463. [Abstract] [Full Text] [PDF]

				D. D. Nedialkova, R. Ulferts, E. van den Born, C. Lauber, A. E. Gorbalenya, J. Ziebuhr, and E. J. Snijder Biochemical Characterization of Arterivirus Nonstructural Protein 11 Reveals the Nidovirus-Wide Conservation of a Replicative Endoribonuclease J. Virol., June 1, 2009; 83(11): 5671 - 5682. [Abstract] [Full Text] [PDF]

				J. Zhang, P. J. Timoney, N. J. MacLachlan, W. H. McCollum, and U. B. R. Balasuriya Persistent Equine Arteritis Virus Infection in HeLa Cells J. Virol., September 1, 2008; 82(17): 8456 - 8464. [Abstract] [Full Text] [PDF]

				M. J. van Hemert, A. H. de Wilde, A. E. Gorbalenya, and E. J. Snijder The in Vitro RNA Synthesizing Activity of the Isolated Arterivirus Replication/Transcription Complex Is Dependent on a Host Factor J. Biol. Chem., June 13, 2008; 283(24): 16525 - 16536. [Abstract] [Full Text] [PDF]

				C. C. Posthuma, K. W. Pedersen, Z. Lu, R. G. Joosten, N. Roos, J. C. Zevenhoven-Dobbe, and E. J. Snijder Formation of the Arterivirus Replication/Transcription Complex: a Key Role for Nonstructural Protein 3 in the Remodeling of Intracellular Membranes J. Virol., May 1, 2008; 82(9): 4480 - 4491. [Abstract] [Full Text] [PDF]

				M. V. Kroese, J. C. Zevenhoven-Dobbe, J. N. A. Bos-de Ruijter, B. P. H. Peeters, J. J. M. Meulenberg, L. A. H. M. Cornelissen, and E. J. Snijder The nsp1{alpha} and nsp1 papain-like autoproteinases are essential for porcine reproductive and respiratory syndrome virus RNA synthesis J. Gen. Virol., February 1, 2008; 89(2): 494 - 499. [Abstract] [Full Text] [PDF]

				M. A. Tijms, D. D. Nedialkova, J. C. Zevenhoven-Dobbe, A. E. Gorbalenya, and E. J. Snijder Arterivirus Subgenomic mRNA Synthesis and Virion Biogenesis Depend on the Multifunctional nsp1 Autoprotease J. Virol., October 1, 2007; 81(19): 10496 - 10505. [Abstract] [Full Text] [PDF]

				N. Beerens, B. Selisko, S. Ricagno, I. Imbert, L. van der Zanden, E. J. Snijder, and B. Canard De Novo Initiation of RNA Synthesis by the Arterivirus RNA-Dependent RNA Polymerase J. Virol., August 15, 2007; 81(16): 8384 - 8395. [Abstract] [Full Text] [PDF]