<i>trans</i>Activity of the Norovirus Camberwell Proteinase and Cleavage of the N-Terminal Protein Encoded by ORF1

Seah, Ee Ling; Marshall, John A.; Wright, P.J.

doi:10.1128/jvi.77.12.7150-7155.2003

Cited by 19 publications

(22 citation statements)

References 35 publications

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“…This result illustrates one level of possible regulation of expression in this system. Demonstration that the mature HuNoV protease can function in trans in cells confirms results with other NoV and calicivirus systems that tested trans protease activity in bacterial or in vitro cell-free translation systems (18)(19)(20)(35)(36)(37)(38) or cells transfected with ORF1 constructs (39). They also suggest that establishment of a cell line that expresses a mutant full-length HuNoV ORF1 construct that includes a reporter protein that would be released for detection after cleavage could lead to a useful assay to detect superinfection with an infectious HuNoV with active protease that could release the reporter.…”

Section: Discussionsupporting

confidence: 57%

Plasmid-based human norovirus reverse genetics system produces reporter-tagged progeny virus containing infectious genomic RNA

Katayama

Murakami

Sharp³

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Significance Human noroviruses are the predominant cause of acute gastroenteritis worldwide, but they remain noncultivatable. A tractable system is needed to understand the host restriction to cultivation. We established a reverse genetics system driven by a mammalian elongation factor-1α promoter without helper virus. This system supports genome replication, particle formation, and particles containing a GFP-marked genomic RNA. RNA from these particles is infectious. The system also produces infectious murine norovirus, confirming its broad applicability to other noroviruses.

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Section: Discussionsupporting

confidence: 57%

Plasmid-based human norovirus reverse genetics system produces reporter-tagged progeny virus containing infectious genomic RNA

Katayama

Murakami

Sharp³

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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“…The ORF1 nonstructural polyproteins of human norovirus strains Southampton virus (SHV), Norwalk virus (NV), Camberwell virus (CV), and MD-145 virus (MDV) have been reported to undergo proteolytic processing at five cleavage sites that would yield six mature cleavage products designated Nterm, NTPase, p18 (p22), VPg, Pro, and Pol (4,5,15,25,26,39,40). In addition, several precursor proteins that represent intermediate forms of polyprotein processing have been described previously (4,5,15,25,39,40). The MNV-1 ORF1 polyprotein is 1,687 aa in length and shows 59 to 64% similarity with the corresponding polyproteins of SHV, NV, CV, and MDV.…”

Section: Resultsmentioning

confidence: 99%

Cleavage Map and Proteolytic Processing of the Murine Norovirus Nonstructural Polyprotein in Infected Cells

Sosnovtsev

Belliot

Chang

et al. 2006

J Virol

196

232

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Murine norovirus (MNV) is presently the only member of the genus Norovirus in the Caliciviridae that can be propagated in cell culture. The goal of this study was to elucidate the proteolytic processing strategy of MNV during an authentic replication cycle in cells. A proteolytic cleavage map of the ORF1 polyprotein was generated, and the virus-encoded 3C-like (3CL) proteinase ( Noroviruses, members of the family Caliciviridae, are the major etiologic agents of nonbacterial epidemic gastroenteritis (13,27,30,46,48). The lack of a cell culture system for human pathogens has necessitated a recombinant DNA-based approach for the classification of circulating strains, the generation of diagnostic tests, and the elucidation of a proposed virus replication strategy. The human noroviruses segregate into three major genogroups (designated GI, GII, and GIV), with multiple genetic clusters, or genotypes, defined within each genogroup (2, 18, 52). The 7.6-to 7.7-kb RNA genome of the noroviruses is organized into three separate open reading frames (ORFs) (ORFs 1, 2, and 3) (17, 23). ORF1 encodes a large nonstructural polyprotein that is processed by the virusencoded 3C-like (3CL) proteinase (Pro) into the mature nonstructural proteins (17, 23, 25). ORF2 encodes the major capsid protein, VP1, and ORF3 encodes a minor structural protein, VP2 (11,17,23).In in vitro experiments, the human norovirus 3CL Pro recognized five cleavage sites within ORF1 with various efficiencies to release six mature cleavage products with the gene order Nterm-NTPase-p20/p22-VPg-Pro-polymerase (Pol) (4,5,15,25,26,39). In addition, several intermediate precursor products were observed in in vitro studies, but their presence during norovirus replication could not be confirmed in the absence of a cell culture system (4, 25).The recent identification of murine norovirus (MNV) and the discovery that it can be propagated in a murine macrophage-like cell line (RAW264.7 [RAW]) provided the first cell culture system to study the molecular mechanisms of norovirus replication (20, 51). The MNV (murine norovirus 1 [MNV-1]) RNA genome is 7,382 nucleotides (nt) in length, with the coding region flanked by a short, 5-nt sequence at the 5Ј end and a 75-nt sequence at the 3Ј end followed by a poly(A) tail (20). The MNV genome is organized into three ORFs with a predicted gene order identical to that of human noroviruses. However, MNV is sufficiently divergent in its sequence to warrant its segregation into a new norovirus genogroup, designated GV (20,52). Northern blot analysis of MNV-infected cells showed the presence of two major positive-strand RNA species corresponding to the genomic and subgenomic RNA, which is characteristic of calicivirus positive-strand RNA replication (51).The goal of our present work was to define the cleavage map of the MNV nonstructural polyprotein and examine proteolytic processing of norovirus proteins during an authentic infection in cell culture. We demonstrate that the MNV 3CL Pro can mediate the cleavage of the MNV nonstructural po...

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“…All genera of caliciviruses other than NoVs have an additional viral protease cleavage site within the region homologous to NS1/2, resulting in two mature viral proteins derived from this region (21)(22)(23). It is possible that some NoVs have lost this cleavage event, but there is one report of additional cleavage of the human NS1/2 protein in cells transfected with HuNoV ORF1 (24), and MNV NS1/2 can be cleaved by caspase 3 (18). NS1/2 localizes to organelles in the secretory pathway (25,26), and HuNoV NS1/2 disrupts protein secretion in transfected cells (25,27).…”

mentioning

confidence: 96%

A Single-Amino-Acid Change in Murine Norovirus NS1/2 Is Sufficient for Colonic Tropism and Persistence

Nice

Strong

McCune

et al. 2013

J Virol

117

172

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Human norovirus (HuNoV) is the major cause of acute nonbacterial gastroenteritis worldwide but has no clear animal reservoir. HuNoV can persist after the resolution of symptoms, and this persistence may be essential for viral maintenance within the population. Many strains of the related murine norovirus (MNV) also persist, providing a tractable animal model for studying norovirus (NoV) persistence. We have used recombinant cDNA clones of representative persistent (CR6) and nonpersistent (CW3) strains to identify a domain within the nonstructural gene NS1/2 that is necessary and sufficient for persistence. Furthermore, we found that a single change of aspartic acid to glutamic acid in CW3 NS1/2 was sufficient for persistence. This same conservative change also caused increased growth of CW3 in the proximal colon, which we found to be a major tissue reservoir of MNV persistence, suggesting that NS1/2 determines viral tropism that is necessary for persistence. These findings represent the first identified function for NoV NS1/2 during infection and establish a novel model system for the study of enteric viral persistence.

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transActivity of the Norovirus Camberwell Proteinase and Cleavage of the N-Terminal Protein Encoded by ORF1

Cited by 19 publications

References 35 publications

Plasmid-based human norovirus reverse genetics system produces reporter-tagged progeny virus containing infectious genomic RNA

Plasmid-based human norovirus reverse genetics system produces reporter-tagged progeny virus containing infectious genomic RNA

Cleavage Map and Proteolytic Processing of the Murine Norovirus Nonstructural Polyprotein in Infected Cells

A Single-Amino-Acid Change in Murine Norovirus NS1/2 Is Sufficient for Colonic Tropism and Persistence

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