The nsp1alpha and nsp1 papain-like autoproteinases are essential for porcine reproductive and respiratory syndrome virus RNA synthesis.
The two N-terminal cleavage products, nsp1alpha and nsp1beta, of the replicase polyproteins of porcine reproductive and respiratory syndrome virus (PRRSV) each contain a papain-like autoproteinase domain, which have been named PCPalpha and PCPbeta, respectively. To assess their role in the PRRSV life cycle, substitutions and deletions of the presumed catalytic cysteine and histidine residues of PCPalpha and PCPbeta were introduced into a PRRSV infectious cDNA clone. Mutations that inactivated PCPalpha activity completely blocked subgenomic mRNA synthesis, but did not affect genome replication. In contrast, mutants in which PCPbeta activity was blocked proved to be non-viable and no sign of viral RNA synthesis could be detected, indicating that the correct processing of the nsp1beta/nsp2 cleavage site is essential for PRRSV genome replication. In conclusion, the data presented here show that a productive PRRSV life cycle depends on the correct processing of both the nsp1alpha/nsp1beta and nsp1beta/nsp2 junctions.
Kroese
Michiel V
MV
Wageningen UR, Animal Sciences Group, Division of Infectious Diseases, PO Box 65, 8200 AB Lelystad, The Netherlands.
Zevenhoven-Dobbe
Jessika C
JC
Molecular Virology Laboratory, Department of Medical Microbiology, Center of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands.
Bos-de Ruijter
Judy N A
JNA
Wageningen UR, Animal Sciences Group, Division of Infectious Diseases, PO Box 65, 8200 AB Lelystad, The Netherlands.
Peeters
Ben P H
BPH
Wageningen UR, Animal Sciences Group, Division of Infectious Diseases, PO Box 65, 8200 AB Lelystad, The Netherlands.
Meulenberg
Janneke J M
JJM
Wageningen UR, Animal Sciences Group, Division of Infectious Diseases, PO Box 65, 8200 AB Lelystad, The Netherlands.
Cornelissen
Lisette A H M
LAHM
Wageningen UR, Animal Sciences Group, Division of Infectious Diseases, PO Box 65, 8200 AB Lelystad, The Netherlands.
Snijder
Eric J
EJ
Molecular Virology Laboratory, Department of Medical Microbiology, Center of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands.
D000818:Animals; D010206:Papain / Q000737:chemistry; D010447:Peptide Hydrolases / Q000378:metabolism* / Q000502:physiology; D020815:Polyproteins / Q000235:genetics; D019318:Porcine Reproductive and Respiratory Syndrome / Q000821:virology*; D019316:Porcine respiratory and reproductive syndrome virus / Q000235:genetics / Q000378:metabolism*; D012367:RNA, Viral / Q000096:biosynthesis* / Q000235:genetics; D013552:Swine; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication / Q000502:physiology*
D020815:Polyproteins; D012367:RNA, Viral; D017361:Viral Nonstructural Proteins; D010447:Peptide Hydrolases; D010206:Papain