scholarly journals Hepatitis C Virus NS2 Protein Suppresses RNA Interference in Cells

2019 ◽  
Vol 35 (4) ◽  
pp. 436-444 ◽  
Author(s):  
Hui Zhou ◽  
Qi Qian ◽  
Ting Shu ◽  
Jiuyue Xu ◽  
Jing Kong ◽  
...  
2004 ◽  
Vol 48 (8) ◽  
pp. 591-598 ◽  
Author(s):  
Yuki Takigawa ◽  
Motoko Nagano-Fujii ◽  
Lin Deng ◽  
Rachmat Hidajat ◽  
Motofumi Tanaka ◽  
...  

2004 ◽  
Vol 78 (18) ◽  
pp. 9713-9720 ◽  
Author(s):  
Nobuhiko Kanazawa ◽  
Masayuki Kurosaki ◽  
Naoya Sakamoto ◽  
Nobuyuki Enomoto ◽  
Yasuhiro Itsui ◽  
...  

ABSTRACT Cellular antiviral responses are mediated partly by the expression of interferon-stimulated genes, triggered by viral genomes, their transcripts and replicative intermediates. Persistent replication of a hepatitis C virus (HCV) replicon suggests that the replicon does not elicit cellular innate antiviral responses. In the present study, we investigated regulatory factors of the interferon-mediated antiviral system in cells expressing an HCV replicon. Luciferase reporter assays revealed that the baseline activity of the interferon-stimulated response element (ISRE) was significantly lower in cells harboring the replicon than in naive cells. Among the proteins involved in the IFN/Jak/STAT pathway and in ISRE activity, the expression level of interferon regulatory factor 1 (IRF-1) was found to be significantly lower in cells harboring the replicon. Transfection of an IRF-1 expression construct into cells harboring the replicon caused an increase of ISRE activity, accompanied by suppression of expression of the HCV replicon. Moreover, in cured Huh7 cells from which the HCV replicon had been eliminated, the expression levels of IRF-1 and ISRE activity also were suppressed, demonstrating that the decrease of IRF-1 is attributable, not to active suppression by the viral proteins, but to adaptation of cells that enables replication of the HCV subgenome. The high permissiveness of the cured cells for the replicon was abolished by transgenic supplementation of IRF-1 expression. Taken together, IRF-1 is one of the key host factors that regulate intracellular HCV replication through modulation of interferon-stimulated-gene-mediated antiviral responses.


2020 ◽  
Vol 112 (5) ◽  
pp. 140-151
Author(s):  
Camille M.H. Clément ◽  
Maika S. Deffieu ◽  
Cristina M. Dorobantu ◽  
Thomas F. Baumert ◽  
Nilda Vanesa Ayala‐Nunez ◽  
...  

2007 ◽  
Vol 6 (3) ◽  
pp. 174-180 ◽  
Author(s):  
Laura Trejo-Ávila; ◽  
Regina Elizondo-González; ◽  
Karina del C. Trujillo-Murillo; ◽  
Pablo Zapata-Benavides; ◽  
Cristina Rodríguez-Padilla; ◽  
...  

2006 ◽  
Vol 50 (12) ◽  
pp. 3984-3991 ◽  
Author(s):  
Vanessa Escuret ◽  
Amaury Martin ◽  
David Durantel ◽  
Romain Parent ◽  
Olivier Hantz ◽  
...  

ABSTRACT Hepatitis C virus (HCV) treatment is based on the association of pegylated alpha interferon (IFN-α) and ribavirin. To improve the level of sustained virological response to treatment, especially in patients infected with HCV genotype 1, new IFNs with improved efficacy and toxicity profiles may be developed. In this report, we show that, in the BM4-5 cell line harboring an HCV subgenomic replicon, a novel and naturally occurring human IFN-α17 variant, GEA007.1, which was discovered by using an original population genetics-based drug discovery approach, inhibits HCV genotype 1 RNA replication more efficiently than does IFN-α2b. Moreover, we show that complete viral clearance is obtained in BM4-5 cells after long-term treatment with GEA007.1, while HCV subgenomic RNA is still detected in cells treated with other IFN-α variants or with standard IFN-α2b. Eventually, we demonstrate that the better inhibitory activity of GEA007.1 compared to that of standard IFN-α is likely to be due to stronger and faster activation of the JAK-STAT signaling pathway and to broader expression of IFN-α-responsive genes in cells. Our results demonstrate a superior inhibitory activity of GEA007.1 over that of IFN-α2b in the HCV replicon system. Clinical trials are required to determine whether GEA007.1 could be a potent “next generation” IFN for the treatment of HCV infection, especially in nonresponders or relapsing patients infected with HCV genotype 1 who currently represent a clinical unmet need.


2010 ◽  
Vol 52 ◽  
pp. S251
Author(s):  
B. Bürgel ◽  
M. Friesland ◽  
A. Koch ◽  
M.P. Manns ◽  
H. Wedemeyer ◽  
...  

2008 ◽  
Vol 83 (2) ◽  
pp. 612-621 ◽  
Author(s):  
Kamile Yuksek ◽  
Wen-ling Chen ◽  
David Chien ◽  
Jing-hsiung James Ou

ABSTRACT Hepatitis C virus (HCV) F protein is encoded by the +1 reading frame of the viral genome. It overlaps with the core protein coding sequence, and multiple mechanisms for its expression have been proposed. The full-length F protein that is synthesized by translational ribosomal frameshift at codons 9 to 11 of the core protein sequence is a labile protein. By using a combination of genetic, biochemical, and cell biological approaches, we demonstrate that this HCV F protein can bind to the proteasome subunit protein α3, which reduces the F-protein level in cells in a dose-dependent manner. Deletion-mapping analysis identified amino acids 40 to 60 of the F protein as the α3-binding domain. This α3-binding domain of the F protein together with its upstream sequence could significantly destabilize the green fluorescent protein, an otherwise stable protein. Further analyses using an F-protein mutant lacking lysine and a cell line that contained a temperature-sensitive E1 ubiquitin-activating enzyme indicated that the degradation of the F protein was ubiquitin independent. Based on these observations as well as the observation that the F protein could be degraded directly by the 20S proteasome in vitro, we propose that the full-length HCV F protein as well as the F protein initiating from codon 26 is degraded by an ubiquitin-independent pathway that is mediated by the proteasome subunit α3. The ability of the F protein to bind to α3 raises the possibility that the HCV F protein may regulate protein degradation in cells.


2005 ◽  
Vol 79 (24) ◽  
pp. 15578-15581 ◽  
Author(s):  
E. Rodríguez-Íñigo ◽  
J. Bartolomé ◽  
N. Ortiz-Movilla ◽  
C. Platero ◽  
J. M. López-Alcorocho ◽  
...  

ABSTRACT In this work, we have shown that hepatitis C virus (HCV) and hepatitis B virus (HBV) can coexist in the same hepatocyte using double fluorescent in situ hybridization in liver biopsy samples from patients with chronic HCV infection with occult HBV infection. Digital image analysis of hybridization signals showed that the HBV DNA levels in coinfected hepatocytes were lower than those in cells infected only with HBV. This finding supports the hypothesis of inhibition of HBV replication by HCV. Furthermore, HCV RNA levels were lower in coinfected cells than in cells infected only with HCV, suggesting that HBV may also inhibit HCV replication.


2011 ◽  
Vol 85 (24) ◽  
pp. 13185-13194 ◽  
Author(s):  
S. Taguwa ◽  
H. Kambara ◽  
N. Fujita ◽  
T. Noda ◽  
T. Yoshimori ◽  
...  

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