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NS3

About: NS3 is a(n) research topic. Over the lifetime, 2687 publication(s) have been published within this topic receiving 129709 citation(s).

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Journal ArticleDOI: 10.1126/SCIENCE.285.5424.110
Volker Lohmann1, Frank Körner1, Joachim Koch1, U. Herian1  +2 moreInstitutions (1)
02 Jul 1999-Science
Abstract: An estimated 170 million persons worldwide are infected with hepatitis C virus (HCV), a major cause of chronic liver disease. Despite increasing knowledge of genome structure and individual viral proteins, studies on virus replication and pathogenesis have been hampered by the lack of reliable and efficient cell culture systems. A full-length consensus genome was cloned from viral RNA isolated from an infected human liver and used to construct subgenomic selectable replicons. Upon transfection into a human hepatoma cell line, these RNAs were found to replicate to high levels, permitting metabolic radiolabeling of viral RNA and proteins. This work defines the structure of HCV replicons functional in cell culture and provides the basis for a long-sought cellular system that should allow detailed molecular studies of HCV and the development of antiviral drugs.

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Topics: NS2-3 protease (63%), NS5B (62%), Viral replication (60%) ...read more

2,924 Citations


Open accessJournal ArticleDOI: 10.1073/PNAS.0408824102
Kui Li1, Eileen Foy2, Josephine C. Ferreon1, Mitsuyasu Nakamura1  +5 moreInstitutions (3)
Abstract: Toll-like receptors (TLRs) bind pathogen-specific ligands early in infection, initiating signaling pathways that lead to expression of multiple protective cellular genes. Many viruses have evolved strategies that block the effector mechanisms induced through these signaling pathways, but viral interference with critical proximal receptor interactions has not been described. We show here that the NS3/4A serine protease of hepatitis C virus (HCV), a virus notorious for its ability to establish persistent intrahepatic infection, causes specific proteolysis of Toll-IL-1 receptor domain-containing adaptor inducing IFN-beta (TRIF or TICAM-1), an adaptor protein linking TLR3 to kinases responsible for activating IFN regulatory factor 3 (IRF-3) and NF-kappaB, transcription factors controlling a multiplicity of antiviral defenses. NS3/4A-mediated cleavage of TRIF reduces its abundance and inhibits polyI:C-activated signaling through the TLR3 pathway before its bifurcation to IRF-3 and NF-kappaB. This uniquely broad mechanism of immune evasion potentially limits expression of multiple host defense genes, thereby promoting persistent infections with this medically important virus.

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Topics: NS2-3 protease (63%), TRIF (61%), Toll-like receptor (59%) ...read more

1,080 Citations


Open accessJournal ArticleDOI: 10.1128/JVI.67.3.1385-1395.1993
Arash Grakoui1, C. Wychowski1, Chih-Ping Lin1, Stephen M. Feinstone1  +1 moreInstitutions (1)
Abstract: Hepatitis C virus (HCV) is the major cause of transfusion-acquired non-A, non-B hepatitis. HCV is an enveloped positive-sense RNA virus which has been classified as a new genus in the flavivirus family. Like the other two genera in this family, the flaviviruses and the pestiviruses, HCV polypeptides appear to be produced by translation of a long open reading frame and subsequent proteolytic processing of this polyprotein. In this study, a cDNA clone encompassing the long open reading frame of the HCV H strain (3,011 amino acid residues) has been assembled and sequenced. This clone and various truncated derivatives were used in vaccinia virus transient-expression assays to map HCV-encoded polypeptides and to study HCV polyprotein processing. HCV polyproteins and cleavage products were identified by using convalescent human sera and a panel of region-specific polyclonal rabbit antisera. Similar results were obtained for several mammalian cell lines examined, including the human HepG2 hepatoma line. The data indicate that at least nine polypeptides are produced by cleavage of the HCV H strain polyprotein. Putative structural proteins, located in the N-terminal one-fourth of the polyprotein, include the capsid protein C (21 kDa) followed by two possible virion envelope proteins, E1 (31 kDa) and E2 (70 kDa), which are heavily modified by N-linked glycosylation. The remainder of the polyprotein probably encodes nonstructural proteins including NS2 (23 kDa), NS3 (70 kDa), NS4A (8 kDa), NS4B (27 kDa), NS5A (58 kDa), and NS5B (68 kDa). An 82- to 88-kDa glycoprotein which reacted with both E2 and NS2-specific HCV antisera was also identified (called E2-NS2). Preliminary results suggest that a fraction of E1 is associated with E2 and E2-NS2 via disulfide linkages.

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Topics: NS3 (63%), NS2-3 protease (60%), NS5B (53%) ...read more

969 Citations


Open accessJournal ArticleDOI: 10.1038/NATURE08960
Min Gao1, Richard E. Nettles1, Makonen Belema, Lawrence B. Snyder  +14 moreInstitutions (1)
06 May 2010-Nature
Abstract: The worldwide prevalence of chronic hepatitis C virus (HCV) infection is estimated to be approaching 200 million people. Current therapy relies upon a combination of pegylated interferon-alpha and ribavirin, a poorly tolerated regimen typically associated with less than 50% sustained virological response rate in those infected with genotype 1 virus. The development of direct-acting antiviral agents to treat HCV has focused predominantly on inhibitors of the viral enzymes NS3 protease and the RNA-dependent RNA polymerase NS5B. Here we describe the profile of BMS-790052, a small molecule inhibitor of the HCV NS5A protein that exhibits picomolar half-maximum effective concentrations (EC(50)) towards replicons expressing a broad range of HCV genotypes and the JFH-1 genotype 2a infectious virus in cell culture. In a phase I clinical trial in patients chronically infected with HCV, administration of a single 100-mg dose of BMS-790052 was associated with a 3.3 log(10) reduction in mean viral load measured 24 h post-dose that was sustained for an additional 120 h in two patients infected with genotype 1b virus. Genotypic analysis of samples taken at baseline, 24 and 144 h post-dose revealed that the major HCV variants observed had substitutions at amino-acid positions identified using the in vitro replicon system. These results provide the first clinical validation of an inhibitor of HCV NS5A, a protein with no known enzymatic function, as an approach to the suppression of virus replication that offers potential as part of a therapeutic regimen based on combinations of HCV inhibitors.

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Topics: NS5B (58%), Viral load (57%), Hepatitis C virus (56%) ...read more

898 Citations


Journal ArticleDOI: 10.1038/NATURE02099
13 Nov 2003-Nature
Abstract: Hepatitis C virus (HCV) infection is a serious cause of chronic liver disease worldwide with more than 170 million infected individuals at risk of developing significant morbidity and mortality. Current interferon-based therapies are suboptimal especially in patients infected with HCV genotype 1, and they are poorly tolerated, highlighting the unmet medical need for new therapeutics. The HCV-encoded NS3 protease is essential for viral replication and has long been considered an attractive target for therapeutic intervention in HCV-infected patients. Here we identify a class of specific and potent NS3 protease inhibitors and report the evaluation of BILN 2061, a small molecule inhibitor biologically available through oral ingestion and the first of its class in human trials. Administration of BILN 2061 to patients infected with HCV genotype 1 for 2 days resulted in an impressive reduction of HCV RNA plasma levels, and established proof-of-concept in humans for an HCV NS3 protease inhibitor. Our results further illustrate the potential of the viral-enzyme-targeted drug discovery approach for the development of new HCV therapeutics.

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Topics: Protease inhibitor (pharmacology) (61%), Danoprevir (57%), Hepatitis C virus (55%) ...read more

876 Citations


Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202149
202059
201984
201870
201784
201684

Top Attributes

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Topic's top 5 most impactful authors

Charles M. Rice

47 papers, 8.7K citations

Ralf Bartenschlager

45 papers, 7.9K citations

Christian Steinkühler

33 papers, 2.4K citations

F. George Njoroge

22 papers, 1.1K citations

Montse Llinas-Brunet

20 papers, 2.1K citations

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