Induction of HOX genes by HCV infection via impairment of histone H2A monoubiquitination.

Hepatitis C virus (HCV) infection causes liver pathologies, including hepatocellular carcinoma (HCC). Homeobox (HOX) gene products regulate embryonic development and are associated with tumorigenesis, although the regulation of HOX genes by HCV infection has not been clarified in detail. We examined the effect of HCV infection on HOX gene expression. In this study, HCV infection induced more than half of the HOX genes and reduced the level of histone H2A monoubiquitination on lysine (K) 119 (H2Aub), which represses HOX gene promoter activity. HCV infection also promoted proteasome-dependent degradation of RNF2, which is an E3 ligase mediating H2A monoubiquitination as a component of polycomb repressive complex 1. Since full-genomic replicon cells but not subgenomic replicon cells exhibited reduced RNF2 and H2Aub levels and induction of HOX genes, we focused on the core protein. Expression of the core protein reduced the amounts of RNF2 and H2Aub and induced HOX genes. Treatment with LY-411575, which can reduce HCV core protein expression via SPP inhibition without affecting other viral proteins, dose-dependently restored the amounts of RNF2 and H2Aub in HCV-infected cells and impaired the induction of HOX genes and production of viral particles but not viral replication. The chromatin immunoprecipitation assay results also indicated infection- and proteasome-dependent reductions in H2Aub located in HOX gene promoters. These results suggest that HCV infection or core protein induces HOX genes by impairing histone H2A monoubiquitination via a reduction in the RNF2 level.Importance Recently sustained virologic response can be achieved by direct acting antiviral therapy in most of hepatitis C patients. Unfortunately, DAA therapy does not completely eliminate a risk of HCC. Several epigenetic factors, including histone modifications, are well known to contribute to HCV-associated HCC. However, the regulation of histone modifications by HCV infection has not been clarified in detail. In this study, our data suggest that HCV infection or HCV core protein expression impairs monoubiquitination of histone H2A K119 in HOX gene promoter via destabilization of RNF2 and then induces HOX genes. Several lines of evidence suggest that the expression of several HOX genes is dysregulated in certain types of tumors. These findings reveal a novel mechanism of HCV-related histone modification and may provide information about new targets for diagnosis and prevention of HCC occurrence.

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Immunoglobulin M reactivity towards the inununologically active region sp75 of the core protein of hepatitis C virus (HCV) in chronic HCV infection

Journal of Medical Virology ◽

10.1002/jmv.1890390412 ◽

1993 ◽

Vol 39 (4) ◽

pp. 325-332 ◽

Cited By ~ 28

Author(s):

U. B. Hellström ◽

S. P. E. Sylvan ◽

R. H. Decker ◽

A. Sönnerborg

Keyword(s):

Hepatitis C Virus ◽

Hepatitis C ◽

Active Region ◽

Core Protein ◽

Immunoglobulin M ◽

Hcv Infection ◽

The Core ◽

Chronic Hcv Infection ◽

Chronic Hcv

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

Journal of Virology ◽

10.1128/jvi.77.19.10237-10249.2003 ◽

2003 ◽

Vol 77 (19) ◽

pp. 10237-10249 ◽

Cited By ~ 116

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.

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Hepatitis C Virus (HCV) Infection, Monoclonal Immunoglobulin Specific for HCV Core Protein, and Plasma-Cell Malignancy

Blood ◽

10.1182/blood.v112.11.2712.2712 ◽

2008 ◽

Vol 112 (11) ◽

pp. 2712-2712

Author(s):

Edith Bigot-Corbel ◽

Michelle Gassin ◽

Isabelle Corre ◽

Didier Le Carrer ◽

Odile Delaroche ◽

...

Keyword(s):

Hepatitis C Virus ◽

Hepatitis C ◽

Plasma Cell ◽

Core Protein ◽

Hcv Infection ◽

Monoclonal Immunoglobulin ◽

Hcv Core Protein ◽

Increased Risk ◽

Genotype 2 ◽

Cell Malignancy

Abstract Hepatitis C virus (HCV) infection can lead to B-cell malignancy via direct infection and transformation of B-lymphocytes, or via indirect transformation by chronic antigen-driven stimulation. Both mechanisms may occur simultaneously, as we previously reported in a case of HCV infection followed by plasma-cell leukemia (PCL), where blasts were infected with HCV and the monoclonal immunoglobulin (Ig) they produced was directed against the core protein of the virus (New Engl J Med, 2003; 348:178). Approximately 10% of HCV-positive patients develop a monoclonal Ig, the specificity of which is usually unknown. To evaluate the link between chronic HCV-antigen driven stimulation and plasma–cell transformation, we studied the specificity of monoclonal Ig developed in the context of HCV infection. Over a period of 13 months, sera from patients consulting or hospitalised at the Centre Hospitalier Universitaire of Nantes found positive for monoclonal Ig, were systematically tested for the presence of HCV RNA and anti-HCV Ig. Among the 700 patients thus studied, 10 (1.4%) were found positive for HCV. Purification of the monoclonal Ig was achieved for 7/10 patients. Using immunoblotting, the purified monoclonal Ig (2 IgG, 1 IgA, 1 IgM) of 4 patients, all with HCV genotype 2, recognized the C22–3 fragment of HCV-core protein; 2 (IgG) recognized NS-4 and 1 did not recognize HCV. Among the 4 patients with anti-HCV-core monoclonal Ig, two presented with mixed (type II) cryoglobulinemia and one was diagnosed with multiple myeloma. Hence, 2/5 patients with anti-HCV core monoclonal Ig developed plasma-cell malignancy. Anti-HCV treatment resulted in the disappearance of the monoclonal Ig for 3/3 treated patients. In summary, in the context of HCV infection monoclonal Ig were typically directed against the virus, and could distinguish patients with increased risk of plasma-cell malignancy. Efforts should be made to identify such patients, as anti-viral therapy should help eradicate the HCV-driven plasma-cell clone.

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Interaction of Hepatitis C Virus Core Protein with Viral Sense RNA and Suppression of Its Translation

Journal of Virology ◽

10.1128/jvi.73.12.9718-9725.1999 ◽

1999 ◽

Vol 73 (12) ◽

pp. 9718-9725 ◽

Cited By ~ 117

Author(s):

Takashi Shimoike ◽

Shigetaka Mimori ◽

Hideki Tani ◽

Yoshiharu Matsuura ◽

Tatsuo Miyamura

Keyword(s):

Hepatitis C Virus ◽

Hepatitis C ◽

Core Protein ◽

Firefly Luciferase ◽

Encephalomyocarditis Virus ◽

Hcv Rna ◽

Dependent Manner ◽

Genomic Rna ◽

The Core ◽

Hcv Core Protein

ABSTRACT To clarify the binding properties of hepatitis C virus (HCV) core protein and its viral RNA for the encapsidation, morphogenesis, and replication of HCV, the specific interaction of HCV core protein with its genomic RNA synthesized in vitro was examined in an in vivo system. The positive-sense RNA from the 5′ end to nucleotide (nt) 2327, which covers the 5′ untranslated region (5′UTR) and a part of the coding region of HCV structural proteins, interacted with HCV core protein, while no interaction was observed in the same region of negative-sense RNA and in other regions of viral and antiviral sense RNAs. The internal ribosome entry site (IRES) exists around the 5′UTR of HCV; therefore, the interaction of the core protein with this region of HCV RNA suggests that there is some effect on its cap-independent translation. Cells expressing HCV core protein were transfected with reporter RNAs consisting of nt 1 to 709 of HCV RNA (the 5′UTR of HCV and about two-thirds of the core protein coding regions) followed by a firefly luciferase gene (HCV07Luc RNA). The translation of HCV07Luc RNA was suppressed in cells expressing the core protein, whereas no significant suppression was observed in the case of a reporter RNA possessing the IRES of encephalomyocarditis virus followed by a firefly luciferase. This suppression by the core protein occurred in a dose-dependent manner. The expression of the E1 envelope protein of HCV or β-galactosidase did not suppress the translation of both HCV and EMCV reporter RNAs. We then examined the regions that are important for suppression of translation by the core protein and found that the region from nt 1 to 344 was enough to exert this suppression. These results suggest that the HCV core protein interacts with viral genomic RNA at a specific region to form nucleocapsids and regulates the expression of HCV by interacting with the 5′UTR.

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Hepatitis C virus (HCV) infection, monoclonal immunoglobulin specific for HCV core protein, and plasma-cell malignancy

Blood ◽

10.1182/blood-2008-07-167569 ◽

2008 ◽

Vol 112 (10) ◽

pp. 4357-4358 ◽

Cited By ~ 11

Author(s):

Edith Bigot-Corbel ◽

Michelle Gassin ◽

Isabelle Corre ◽

Didier Le Carrer ◽

Odile Delaroche ◽

...

Keyword(s):

Hepatitis C Virus ◽

Hepatitis C ◽

Plasma Cell ◽

Core Protein ◽

Hcv Infection ◽

Monoclonal Immunoglobulin ◽

Hcv Core Protein ◽

Cell Malignancy

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Intramembrane Processing by Signal Peptide Peptidase Regulates the Membrane Localization of Hepatitis C Virus Core Protein and Viral Propagation

Journal of Virology ◽

10.1128/jvi.00306-08 ◽

2008 ◽

Vol 82 (17) ◽

pp. 8349-8361 ◽

Cited By ~ 75

Author(s):

Kiyoko Okamoto ◽

Yoshio Mori ◽

Yasumasa Komoda ◽

Toru Okamoto ◽

Masayasu Okochi ◽

...

Keyword(s):

Hepatitis C Virus ◽

Hepatitis C ◽

Signal Peptide ◽

Core Protein ◽

Biological Significance ◽

Signal Peptidase ◽

Signal Peptide Peptidase ◽

Viral Propagation ◽

The Core ◽

Hcv Core Protein

ABSTRACT Hepatitis C virus (HCV) core protein has shown to be localized in the detergent-resistant membrane (DRM), which is distinct from the classical raft fraction including caveolin, although the biological significance of the DRM localization of the core protein has not been determined. The HCV core protein is cleaved off from a precursor polyprotein at the lumen side of Ala191 by signal peptidase and is then further processed by signal peptide peptidase (SPP) within the transmembrane region. In this study, we examined the role of SPP in the localization of the HCV core protein in the DRM and in viral propagation. The C terminus of the HCV core protein cleaved by SPP in 293T cells was identified as Phe177 by mass spectrometry. Mutations introduced into two residues (Ile176 and Phe177) upstream of the cleavage site of the core protein abrogated processing by SPP and localization in the DRM fraction. Expression of a dominant-negative SPP or treatment with an SPP inhibitor, L685,458, resulted in reductions in the levels of processed core protein localized in the DRM fraction. The production of HCV RNA in cells persistently infected with strain JFH-1 was impaired by treatment with the SPP inhibitor. Furthermore, mutant JFH-1 viruses bearing SPP-resistant mutations in the core protein failed to propagate in a permissive cell line. These results suggest that intramembrane processing of HCV core protein by SPP is required for the localization of the HCV core protein in the DRM and for viral propagation.

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Hepatitis C Virus Genotype 1b Core Protein Does Not Exert Immunomodulatory Effects on Virus-Induced Cellular Immunity

Journal of Virology ◽

10.1128/jvi.76.3.990-997.2002 ◽

2002 ◽

Vol 76 (3) ◽

pp. 990-997 ◽

Cited By ~ 21

Author(s):

Zhang-Xu Liu ◽

Hiroshi Nishida ◽

Jian-Wen He ◽

Michael M. C. Lai ◽

Ni Feng ◽

...

Keyword(s):

Hepatitis C Virus ◽

Hepatitis C ◽

Liver Injury ◽

Core Protein ◽

Virus Genotype ◽

Hcv Genotype ◽

Cell Functions ◽

The Core ◽

Genotype 1B ◽

Hcv Core Protein

ABSTRACT The hepatitis C virus (HCV) core protein is among the most conserved proteins in HCV and is known to induce sensitization of cytotoxic T lymphocytes (CTL). Therefore, it is a prime candidate for a component of a potential HCV vaccine. The HCV core protein has, however, been reported to exert multiple effects on cell functions, raising questions as to its suitability for this purpose. This question was investigated here with mice into which replication-deficient adenoviruses expressing core protein of an HCV genotype 1b isolate were injected. We show that induction of cytokines in response to the infection, infiltration of lymphocytes into the infected liver, priming of virus-specific CTL, and liver injury are not modulated by expression of the core protein in the liver. Moreover, no changes in the sensitivity to tumor necrosis factor alpha- or Fas-mediated liver injury are demonstrable. A similar lack of demonstrable effects of the core protein on immune functions has also been obtained using transgenic mice expressing another HCV genotype 1b core protein. It is concluded that the HCV core protein of genotype 1b has no modulatory effects on induction of virus-specific immune responses and may therefore be a suitable component of an HCV vaccine.

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Characterization of Hepatitis C Virus Core Protein Multimerization and Membrane Envelopment: Revelation of a Cascade of Core-Membrane Interactions

Journal of Virology ◽

10.1128/jvi.00066-09 ◽

2009 ◽

Vol 83 (19) ◽

pp. 9923-9939 ◽

Cited By ~ 23

Author(s):

Li-Shuang Ai ◽

Yu-Wen Lee ◽

Steve S.-L. Chen

Keyword(s):

Hepatitis C Virus ◽

Hepatitis C ◽

Complex Formation ◽

Signal Peptide ◽

Core Protein ◽

The Core ◽

Hcv Core Protein ◽

Core Proteins ◽

Multimeric Complex ◽

Protein Multimerization

ABSTRACT The molecular basis underlying hepatitis C virus (HCV) core protein maturation and morphogenesis remains elusive. We characterized the concerted events associated with core protein multimerization and interaction with membranes. Analyses of core proteins expressed from a subgenomic system showed that the signal sequence located between the core and envelope glycoprotein E1 is critical for core association with endoplasmic reticula (ER)/late endosomes and the core's envelopment by membranes, which was judged by the core's acquisition of resistance to proteinase K digestion. Despite exerting an inhibitory effect on the core's association with membranes, (Z-LL)2-ketone, a specific inhibitor of signal peptide peptidase (SPP), did not affect core multimeric complex formation, suggesting that oligomeric core complex formation proceeds prior to or upon core attachment to membranes. Protease-resistant core complexes that contained both innate and processed proteins were detected in the presence of (Z-LL)2-ketone, implying that core envelopment occurs after intramembrane cleavage. Mutations of the core that prevent signal peptide cleavage or coexpression with an SPP loss-of-function D219A mutant decreased the core's envelopment, demonstrating that SPP-mediated cleavage is required for core envelopment. Analyses of core mutants with a deletion in domain I revealed that this domain contains sequences crucial for core envelopment. The core proteins expressed by infectious JFH1 and Jc1 RNAs in Huh7 cells also assembled into a multimeric complex, associated with ER/late-endosomal membranes, and were enveloped by membranes. Treatment with (Z-LL)2-ketone or coexpression with D219A mutant SPP interfered with both core envelopment and infectious HCV production, indicating a critical role of core envelopment in HCV morphogenesis. The results provide mechanistic insights into the sequential and coordinated processes during the association of the HCV core protein with membranes in the early phase of virus maturation and morphogenesis.

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Ectopic Expression of Hepatitis C Virus Core Protein Differentially Regulates Nuclear Transcription Factors

Journal of Virology ◽

10.1128/jvi.72.12.9722-9728.1998 ◽

1998 ◽

Vol 72 (12) ◽

pp. 9722-9728 ◽

Cited By ~ 105

Author(s):

Anju Shrivastava ◽

Sunil K. Manna ◽

Ranjit Ray ◽

Bharat B. Aggarwal

Keyword(s):

Transcription Factors ◽

Hepatitis C Virus ◽

Hepatitis C ◽

Inflammatory Responses ◽

Core Protein ◽

Ectopic Expression ◽

Cellular Growth ◽

Mitogen Activated Protein Kinase ◽

The Core ◽

Hcv Core Protein

ABSTRACT The putative core protein of hepatitis C virus (HCV) regulates cellular growth and a number of cellular promoters. To further understand its effect, we investigated the role of the core protein in the endogenous regulation of two distinct transcription factors, nuclear factor-κB (NF-κB) and activating protein-1 (AP-1), and the related mitogen-activated protein kinase kinase (MAPKK) and c-Jun N-terminal kinase (JNK). Stable cell transfectants expressing the HCV core protein suppressed tumor necrosis factor (TNF)-induced NF-κB activation. Supershift analysis revealed that NF-κB consists of p50 and p65 subunits. This correlated with inhibition of the degradation of IκBα, the inhibitory subunit of NF-κB. The effect was not specific to TNF, as suppression in core protein-expressing cells was also observed in response to a number of other inflammatory agents known to activate NF-κB. In contrast to the effect on NF-κB, the HCV core protein constitutively activated AP-1, which correlated with the activation of JNK and MAPKK, which are known to regulate AP-1. These observations indicated that the core protein targets transcription factors known to be involved in the regulation of inflammatory responses and the immune system.

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