scholarly journals Hepatitis C Virus Core Protein Interacts with Cellular Putative RNA Helicase

1999 ◽  
Vol 73 (4) ◽  
pp. 2841-2853 ◽  
Author(s):  
Li-Ru You ◽  
Chun-Ming Chen ◽  
Tien-Shun Yeh ◽  
Tzung-Yuan Tsai ◽  
Ru-Tsun Mai ◽  
...  
Keyword(s):  
Gene Expression ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Amino Acid ◽  
Core Protein ◽  
Rna Helicase ◽  
Host Cells ◽  
Luciferase Reporter ◽  
Rna Helicases ◽  
Hcv Core Protein

ABSTRACT The nucleocapsid core protein of hepatitis C virus (HCV) has been shown to trans-act on several viral or cellular promoters. To get insight into the trans-action mechanism of HCV core protein, a yeast two-hybrid cloning system was used for identification of core protein-interacting cellular protein. One such cDNA clone encoding the DEAD box family of putative RNA helicase was obtained. This cellular putative RNA helicase, designated CAP-Rf, exhibits more than 95% amino acid sequence identity to other known RNA helicases including human DBX and DBY, mouse mDEAD3, and PL10, a family of proteins generally involved in translation, splicing, development, or cell growth. In vitro binding or in vivo coimmunoprecipitation studies demonstrated the direct interaction of the full-length/matured form and C-terminally truncated variants of HCV core protein with this targeted protein. Additionally, the protein’s interaction domains were delineated at the N-terminal 40-amino-acid segment of the HCV core protein and the C-terminal tail of CAP-Rf, which encompassed its RNA-binding and ATP hydrolysis domains. Immunoblotting or indirect immunofluorescence analysis revealed that the endogenous CAP-Rf was mainly localized in the nucleus and to a lesser extent in the cytoplasm, and when fused with FLAG tag, it colocalized with the HCV core protein either in the cytoplasm or in the nucleus. Similar to other RNA helicases, this cellular RNA helicase has nucleoside triphosphatase-deoxynucleoside triphosphatase activity, but this activity is inhibited by various forms of homopolynucleotides and enhanced by the HCV core protein. Moreover, transient expression of HCV core protein in human hepatoma HuH-7 cells significantly potentiated the trans-activation effect of FLAG-tagged CAP-Rf or untagged CAP-Rf on the luciferase reporter plasmid activity. All together, our results indicate that CAP-Rf is involved in regulation of gene expression and that HCV core protein promotes thetrans-activation ability of CAP-Rf, likely via the complex formation and the modulation of the ATPase-dATPase activity of CAP-Rf. These findings provide evidence that HCV may have evolved a distinct mechanism in alteration of host cellular gene expression regulation via the interaction of its nucleocapsid core protein and cellular putative RNA helicase known to participate in all aspects of cellular processes involving RNA metabolism. This feature of core protein may impart pleiotropic effects on host cells, which may partially account for its role in HCV pathogenesis.

scholarly journals Hepatitis C virus core protein impairs metabolic disorder of liver cell via HOTAIR-Sirt1 signalling

2016 ◽  
Vol 36 (3) ◽  
Author(s):  
Zhi-qin Li ◽  
Xin-yu Gu ◽  
Jin-xing Hu ◽  
Yu Ping ◽  
Hua Li ◽  
...  
Keyword(s):  
Gene Expression ◽  
Hepatitis C Virus ◽  
Lipid Metabolism ◽  
Hepatitis C ◽  
Liver Cell ◽  
Core Protein ◽  
Related Gene ◽  
Qrt Pcr ◽  
Glucose And Lipid Metabolism ◽  
Hcv Core Protein

It has been suggested that Hepatitis C virus (HCV) core protein is associated with metabolic disorders of liver cell. However, the precise mechanism is still unclear. The aim of the present study was to explore the impact of HCV core protein on hepatocyte metabolism by HepG2 and the possible involvement of long non-coding (lnc) RNAs in this process. The effect of HCV core protein on lncRNAs expression was examined with quantitative RT-PCR (qRT-PCR). Manipulation of HVC core protein and lncRNA HOTAIR was to evaluate the role of interaction between them on cell metabolism-related gene expression and cellular metabolism. The potential downstream Sirt1 signal was examined by western blotting and qRT-PCR. Our data suggested that suppression of HOTAIR abrogates HCV core protein-induced reduction in Sirt1 and differential expression of glucose- and lipid-metabolism-related genes. Also it benefits for metabolic homoeostasis of hepatocyte indicated by restoration of cellular reactive oxygen species (ROS) level and NAD/NADH ratio. By manipulation of HOTAIR, we concluded that HOTAIR negatively regulates Sirt1 expression through affecting its promotor methylation. Moreover, overexpression of Sirt1 reverses pcDNA-HOTAIR-induced glucose- and lipid-metabolism-related gene expression. Our study suggests that HCV core protein causes dysfunction of glucose and lipid metabolism in liver cells through HOTAIR-Sirt1 signalling pathway.

scholarly journals DDX3 DEAD-Box RNA Helicase Is Required for Hepatitis C Virus RNA Replication

2007 ◽  
Vol 81 (24) ◽  
pp. 13922-13926 ◽  
Author(s):  
Yasuo Ariumi ◽  
Misao Kuroki ◽  
Ken-ichi Abe ◽  
Hiromichi Dansako ◽  
Masanori Ikeda ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Core Protein ◽  
Rna Replication ◽  
Rna Helicase ◽  
Hcv Rna ◽  
Dead Box ◽  
Hcv Core Protein ◽  
Virus Rna ◽  
Culture Supernatants

ABSTRACT DDX3, a DEAD-box RNA helicase, binds to the hepatitis C virus (HCV) core protein. However, the role(s) of DDX3 in HCV replication is still not understood. Here we demonstrate that the accumulation of both genome-length HCV RNA (HCV-O, genotype 1b) and its replicon RNA were significantly suppressed in HuH-7-derived cells expressing short hairpin RNA targeted to DDX3 by lentivirus vector transduction. As well, RNA replication of JFH1 (genotype 2a) and release of the core into the culture supernatants were suppressed in DDX3 knockdown cells after inoculation of the cell culture-generated HCVcc. Thus, DDX3 is required for HCV RNA replication.

scholarly journals Differential Effects on the Hepatitis C Virus (HCV) Internal Ribosome Entry Site by Vitamin B12 and the HCV Core Protein

2004 ◽  
Vol 78 (21) ◽  
pp. 12075-12081 ◽  
Author(s):  
Dongsheng Li ◽  
William B. Lott ◽  
John Martyn ◽  
Gholamreza Haqshenas ◽  
Eric J. Gowans
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Internal Ribosome Entry Site ◽  
Core Protein ◽  
Vitamin B ◽  
Entry Site ◽  
Internal Ribosome Entry ◽  
Hcv Core Protein ◽  
Hcv Ires

ABSTRACT To investigate the role of the hepatitis C virus internal ribosome entry site (HCV IRES) domain IV in translation initiation and regulation, two chimeric IRES elements were constructed to contain the reciprocal domain IV in the otherwise HCV and classical swine fever virus IRES elements. This permitted an examination of the role of domain IV in the control of HCV translation. A specific inhibitor of the HCV IRES, vitamin B12, was shown to inhibit translation directed by all IRES elements which contained domain IV from the HCV and the GB virus B IRES elements, whereas the HCV core protein could only suppress translation from the wild-type HCV IRES. Thus, the mechanisms of translation inhibition by vitamin B12 and the core protein differ, and they target different regions of the IRES.

Hepatitis C virus (HCV) core protein enhances the immunogenicity of a co-delivered DNA vaccine encoding HCV structural antigens in mice

2006 ◽  
Vol 44 (1) ◽  
pp. 9 ◽  
Author(s):  
Marleny González ◽  
Liz Alvarez-Lajonchere ◽  
Julio César Alvarez-Obregón ◽  
Ivis Guerra ◽  
Ariel Viña ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Dna Vaccine ◽  
Core Protein ◽  
Hcv Core Protein

Hepatitis C virus core protein inhibits hepatitis B virus replication by downregulating HBx levels via Siah-1-mediated proteasomal degradation during coinfection

2021 ◽  
Vol 102 (12) ◽  
Author(s):  
Sujeong Lee ◽  
Hyunyoung Yoon ◽  
Jiwoo Han ◽  
Kyung Lib Jang
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Core Protein ◽  
Experimental Studies ◽  
Proteasomal Degradation ◽  
Hbv Replication ◽  
Hcv Core Protein ◽  
B Virus

Most clinical and experimental studies have suggested that hepatitis C virus (HCV) is dominant over hepatitis B virus (HBV) during coinfection, although the mechanism remains unclear. Here, we found that HCV core protein inhibits HBV replication by downregulating HBx levels during coinfection in human hepatoma cells. For this effect, HCV core protein increased reactive oxygen species levels in the mitochondria and activated the ataxia telangiectasia mutated-checkpoint kinase two pathway in the nucleus, resulting in an upregulation of p53 levels. Accordingly, HCV core protein induced p53-dependent activation of seven in absentia homolog one expression, an E3 ligase of HBx, resulting in the ubiquitination and proteasomal degradation of HBx. The effect of the HCV core protein on HBx levels was accurately reproduced in both a 1.2-mer HBV replicon and in vitro HBV infection systems, providing evidence for the inhibition of HBV replication by HCV core protein. The present study may provide insights into the mechanism of HCV dominance in HBV- and HCV-coinfected patients.

scholarly journals Cytokine-Modulated Natural Killer Cells Differentially Regulate the Activity of the Hepatitis C Virus

2018 ◽  
Vol 19 (9) ◽  
pp. 2771 ◽  
Author(s):  
Yoo Cho ◽  
Hwan Lee ◽  
Hyojeung Kang ◽  
Hyosun Cho
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Nk Cells ◽  
Natural Killer ◽  
Core Protein ◽  
Lymphoid Cells ◽  
Hcv Rna ◽  
Cell Infection ◽  
Hcv Core Protein

HCV genotype 2a strain JFH-1 replicates and produces viral particles efficiently in human hepatocellular carcinoma (huh) 7.5 cells, which provide a stable in vitro cell infection system for the hepatitis C virus (HCVcc system). Natural killer (NK) cells are large lymphoid cells that recognize and kill virus-infected cells. In this study, we investigated the interaction between NK cells and the HCVcc system. IL-10 is a typical immune regulatory cytokine that is produced mostly by NK cells and macrophages. IL-21 is one of the main cytokines that stimulate the activation of NK cells. First, we used anti-IL-10 to neutralize IL-10 in a coculture of NK cells and HCVcc. Anti-IL-10 treatment increased the maturation of NK cells by enhancing the frequency of the CD56+dim population in NK-92 cells. However, with anti-IL-10 treatment of NK cells in coculture with J6/JFH-1-huh 7.5 cells, there was a significant decrease in the expression of STAT1 and STAT5 proteins in NK-92 cells and an increase in the HCV Core and NS3 proteins. In addition, rIL-21 treatment increased the frequency of the CD56+dim population in NK-92 cells, Also, there was a dramatic increase in the expression of STAT1 and STAT5 proteins in rIL-21 pre-stimulated NK cells and a decrease in the expression of HCV Core protein in coculture with J6/JFH-1-huh 7.5 cells. In summary, we found that the functional activation of NK cells can be modulated by anti-IL-10 or rIL-21, which controls the expression of HCV proteins as well as HCV RNA replication.

scholarly journals Proteasome Activator PA28γ-Dependent Nuclear Retention and Degradation of Hepatitis C Virus Core Protein

2003 ◽  
Vol 77 (19) ◽  
pp. 10237-10249 ◽  
Author(s):  
Kohji Moriishi ◽  
Tamaki Okabayashi ◽  
Kousuke Nakai ◽  
Kyoji Moriya ◽  
Kazuhiko Koike ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Core Protein ◽  
Regulatory Protein ◽  
Hcv Infection ◽  
Nuclear Retention ◽  
Proteasome Activator ◽  
Hcv Core Protein ◽  
Core Proteins ◽  
Chronic Hcv

ABSTRACT Hepatitis C virus (HCV) core protein plays an important role in the formation of the viral nucleocapsid and a regulatory protein involved in hepatocarcinogenesis. In this study, we have identified proteasome activator PA28γ (11S regulator γ) as an HCV core binding protein by using yeast two-hybrid system. This interaction was demonstrated not only in cell culture but also in the livers of HCV core transgenic mice. These findings are extended to human HCV infection by the observation of this interaction in liver specimens from a patient with chronic HCV infection. Neither the interaction of HCV core protein with other PA28 subtypes nor that of PA28γ with other Flavivirus core proteins was detected. Deletion of the PA28γ-binding region from the HCV core protein or knockout of the PA28γ gene led to the export of the HCV core protein from the nucleus to the cytoplasm. Overexpression of PA28γ enhanced the proteolysis of the HCV core protein. Thus, the nuclear retention and stability of the HCV core protein is regulated via a PA28γ-dependent pathway through which HCV pathogenesis may be exerted.

scholarly journals The Arginine-1493 Residue in QRRGRTGR1493G Motif IV of the Hepatitis C Virus NS3 Helicase Domain Is Essential for NS3 Protein Methylation by the Protein Arginine Methyltransferase 1

2001 ◽  
Vol 75 (17) ◽  
pp. 8031-8044 ◽  
Author(s):  
Jaerang Rho ◽  
Seeyoung Choi ◽  
Young Rim Seong ◽  
Joonho Choi ◽  
Dong-Soo Im
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Rna Binding ◽  
Rna Helicase ◽  
Full Length ◽  
Arginine Residue ◽  
Protein Methylation ◽  
Helicase Domain ◽  
Rna Helicases ◽  
Ns3 Protein

ABSTRACT The NS3 protein of hepatitis C virus (HCV) contains protease and RNA helicase activities, both of which are likely to be essential for HCV propagation. An arginine residue present in the arginine-glycine (RG)-rich region of many RNA-binding proteins is posttranslationally methylated by protein arginine methyltransferases (PRMTs). Amino acid sequence analysis revealed that the NS3 protein contains seven RG motifs, including two potential RG motifs in the 1486-QRRGRTGRG-1494 motif IV of the RNA helicase domain, in which arginines are potentially methylated by PRMTs. Indeed, we found that the full-length NS3 protein is arginine methylated in vivo. The full-length NS3 protein and the NS3 RNA helicase domain were methylated by a crude human cell extract. The purified PRMT1 methylated the full-length NS3 and the RNA helicase domain, but not the NS3 protease domain. The NS3 helicase bound specifically and comigrated with PRMT1 in vitro. Mutational analyses indicate that the Arg1493 in the QRR1488GRTGR1493G region of the NS3 RNA helicase is essential for NS3 protein methylation and that Arg1488 is likely methylated. NS3 protein methylation by the PRMT1 was decreased in the presence of homoribopolymers, suggesting that the arginine-rich motif IV is involved in RNA binding. The results suggest that an arginine residue(s) in QRXGRXGR motif IV conserved in the virus-encoded RNA helicases can be posttranslationally methylated by the PRMT1.

scholarly journals Amino Acid Polymorphisms in Hepatitis C Virus Core Affect Infectious Virus Production and Major Histocompatibility Complex Class I Molecule Expression

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Megumi Tasaka-Fujita ◽  
Nao Sugiyama ◽  
Wonseok Kang ◽  
Takahiro Masaki ◽  
Asako Murayama ◽  
...  
Keyword(s):  
Major Histocompatibility Complex ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Amino Acid ◽  
Mhc Class I ◽  
Infectious Virus ◽  
Core Protein ◽  
Virus Production ◽  
Class I ◽  
Histocompatibility Complex

Abstract Amino acid (aa) polymorphisms in the hepatitis C virus (HCV) genotype 1b core protein have been reported to be a potent predictor for poor response to interferon (IFN)-based therapy and a risk factor for hepatocarcinogenesis. We investigated the effects of these polymorphisms with genotype 1b/2a chimeric viruses that contained polymorphisms of Arg/Gln at aa 70 and Leu/Met at aa 91. We found that infectious virus production was reduced in cells transfected with chimeric virus RNA that had Gln at aa 70 (aa70Q) compared with RNA with Arg at aa 70 (aa70R). Using flow cytometry analysis, we confirmed that HCV core protein accumulated in aa70Q clone transfected cells and it caused a reduction in cell-surface expression of major histocompatibility complex (MHC) class I molecules induced by IFN treatment through enhanced protein kinase R phosphorylation. We could not detect any effects due to the polymorphism at aa 91. In conclusion, the polymorphism at aa 70 was associated with efficiency of infectious virus production and this deteriorated virus production in strains with aa70Q resulted in the intracellular accumulation of HCV proteins and attenuation of MHC class I molecule expression. These observations may explain the strain-associated resistance to IFN-based therapy and hepatocarcinogenesis of HCV.

scholarly journals Hepatitis C Virus-Induced Rab32 Aggregation and Its Implications for Virion Assembly

2016 ◽  
Vol 91 (3) ◽  
Author(s):  
Tu M. Pham ◽  
Si C. Tran ◽  
Yun-Sook Lim ◽  
Soon B. Hwang
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Membrane Trafficking ◽  
Core Protein ◽  
Cell Types ◽  
Viral Assembly ◽  
Intracellular Membrane ◽  
Virion Assembly ◽  
Hcv Core Protein ◽  
Infected Cells

ABSTRACT Hepatitis C virus (HCV) is highly dependent on cellular factors for viral propagation. Using high-throughput next-generation sequencing, we analyzed the host transcriptomic changes and identified 30 candidate genes which were upregulated in cell culture-grown HCV (HCVcc)-infected cells. Of these candidates, we selected Rab32 for further investigation. Rab32 is a small GTPase that regulates a variety of intracellular membrane-trafficking events in various cell types. In this study, we demonstrated that both mRNA and protein levels of Rab32 were increased in HCV-infected cells. Furthermore, we showed that HCV infection converted the predominantly expressed GTP-bound Rab32 to GDP-bound Rab32, contributing to the aggregation of Rab32 and thus making it less sensitive to cellular degradation machinery. In addition, GDP-bound Rab32 selectively interacted with HCV core protein and deposited core protein into the endoplasmic reticulum (ER)-associated Rab32-derived aggregated structures in the perinuclear region, which were likely to be viral assembly sites. Using RNA interference technology, we demonstrated that Rab32 was required for the assembly step but not for other stages of the HCV life cycle. Taken together, these data suggest that HCV may modulate Rab32 activity to facilitate virion assembly. IMPORTANCE Rab32, a member of the Ras superfamily of small GTPases, regulates various intracellular membrane-trafficking events in many cell types. In this study, we showed that HCV infection concomitantly increased Rab32 expression at the transcriptional level and altered the balance between GDP- and GTP-bound Rab32 toward production of Rab32-GDP. GDP-bound Rab32 selectively interacted with HCV core protein and enriched core in the ER-associated Rab32-derived aggregated structures that were probably necessary for viral assembly. Indeed, we showed that Rab32 was specifically required for the assembly of HCV. Collectively, our study identifies that Rab32 is a novel host factor essential for HCV particle assembly.

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