1
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Chen P, Wojdyla JA, Colasanti O, Li Z, Qin B, Wang M, Lohmann V, Cui S. Biochemical and structural characterization of hepatitis A virus 2C reveals an unusual ribonuclease activity on single-stranded RNA. Nucleic Acids Res 2022; 50:9470-9489. [PMID: 35947700 PMCID: PMC9458454 DOI: 10.1093/nar/gkac671] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 07/22/2022] [Indexed: 12/24/2022] Open
Abstract
The HAV nonstructural protein 2C is essential for virus replication; however, its precise function remains elusive. Although HAV 2C shares 24-27% sequence identity with other 2Cs, key motifs are conserved. Here, we demonstrate that HAV 2C is an ATPase but lacking helicase activity. We identified an ATPase-independent nuclease activity of HAV 2C with a preference for polyuridylic single-stranded RNAs. We determined the crystal structure of an HAV 2C fragment to 2.2 Å resolution, containing an ATPase domain, a region equivalent to enterovirus 2C zinc-finger (ZFER) and a C-terminal amphipathic helix (PBD). The PBD of HAV 2C occupies a hydrophobic pocket (Pocket) in the adjacent 2C, and we show the PBD-Pocket interaction is vital for 2C functions. We identified acidic residues that are essential for the ribonuclease activity and demonstrated mutations at these sites abrogate virus replication. We built a hexameric-ring model of HAV 2C, revealing the ribonuclease-essential residues clustering around the central pore of the ring, whereas the ATPase active sites line up at the gaps between adjacent 2Cs. Finally, we show the ribonuclease activity is shared by other picornavirus 2Cs. Our findings identified a previously unfound activity of picornavirus 2C, providing novel insights into the mechanisms of virus replication.
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Affiliation(s)
| | | | | | | | - Bo Qin
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, PR China
| | - Meitian Wang
- Swiss Light Source at the Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - Volker Lohmann
- Correspondence may also be addressed to Volker Lohmann. Tel: +49 6221 56 6449; Fax: +49 6221 56 4570;
| | - Sheng Cui
- To whom correspondence should be addressed. Tel: +86 10 67828669; Fax: +86 10 67855012;
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2
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Abstract
Hepatitis A virus (HAV) is a faeco-orally transmitted picornavirus and is one of the main causes of acute hepatitis worldwide. An overview of the molecular biology of HAV is presented with an emphasis on recent findings. Immune evasion strategies and a possible correlation between HAV and atopy are discussed as well. Despite the availability of efficient vaccines, antiviral drugs targeting HAV are required to treat severe cases of fulminant hepatitis, contain outbreaks, and halt the potential spread of vaccine-escape variants. Additionally, such drugs could be used to shorten the period of illness and decrease associated economical costs. Several known inhibitors of HAV with various mechanisms of action will be discussed. Since none of these molecules is readily useable in the clinic and since the availability of an anti-HAV drug would be of clinical importance, increased efforts should be targeted toward discovery and development of such antivirals.
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Affiliation(s)
- Yannick Debing
- Rega Institute for Medical ResearchUniversity of LeuvenLeuvenBelgium
| | - Johan Neyts
- Rega Institute for Medical ResearchUniversity of LeuvenLeuvenBelgium
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3
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Herod MR, Jones DM, McLauchlan J, McCormick CJ. Increasing rate of cleavage at boundary between non-structural proteins 4B and 5A inhibits replication of hepatitis C virus. J Biol Chem 2011; 287:568-580. [PMID: 22084249 DOI: 10.1074/jbc.m111.311407] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
In hepatitis C virus, non-structural proteins are cleaved from the viral polyprotein by viral encoded proteases. Although proteolytic processing goes to completion, the rate of cleavage differs between different boundaries, primarily due to the sequence at these positions. However, it is not known whether slow cleavage is important for viral replication or a consequence of restrictions on sequences that can be tolerated at the cleaved ends of non-structural proteins. To address this question, mutations were introduced into the NS4B side of the NS4B5A boundary, and their effect on replication and polyprotein processing was examined in the context of a subgenomic replicon. Single mutations that modestly increased the rate of boundary processing were phenotypically silent, but a double mutation, which further increased the rate of boundary cleavage, was lethal. Rescue experiments relying on viral RNA polymerase-induced error failed to identify second site compensatory mutations. Use of a replicon library with codon degeneracy did allow identification of second site compensatory mutations, some of which fell exclusively within the NS5A side of the boundary. These mutations slowed boundary cleavage and only enhanced replication in the context of the original lethal NS4B double mutation. Overall, the data indicate that slow cleavage of the NS4B5A boundary is important and identify a previously unrecognized role for NS4B5A-containing precursors requiring them to exist for a minimum finite period of time.
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Affiliation(s)
- Morgan R Herod
- Sir Henry Wellcome Laboratories, Division of Infection, Inflammation and Immunity, School of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom
| | - Daniel M Jones
- Medical Research Council-University of Glasgow Centre for Virus Research, 8 Church Street, Glasgow G11 5JR, Scotland, United Kingdom
| | - John McLauchlan
- Medical Research Council-University of Glasgow Centre for Virus Research, 8 Church Street, Glasgow G11 5JR, Scotland, United Kingdom
| | - Christopher J McCormick
- Sir Henry Wellcome Laboratories, Division of Infection, Inflammation and Immunity, School of Medicine, University of Southampton, Southampton SO16 6YD, United Kingdom.
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4
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Qu L, Feng Z, Yamane D, Liang Y, Lanford RE, Li K, Lemon SM. Disruption of TLR3 signaling due to cleavage of TRIF by the hepatitis A virus protease-polymerase processing intermediate, 3CD. PLoS Pathog 2011; 7:e1002169. [PMID: 21931545 PMCID: PMC3169542 DOI: 10.1371/journal.ppat.1002169] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Accepted: 06/01/2011] [Indexed: 01/19/2023] Open
Abstract
Toll-like receptor 3 (TLR3) and cytosolic RIG-I-like helicases (RIG-I and MDA5) sense viral RNAs and activate innate immune signaling pathways that induce expression of interferon (IFN) through specific adaptor proteins, TIR domain-containing adaptor inducing interferon-β (TRIF), and mitochondrial antiviral signaling protein (MAVS), respectively. Previously, we demonstrated that hepatitis A virus (HAV), a unique hepatotropic human picornavirus, disrupts RIG-I/MDA5 signaling by targeting MAVS for cleavage by 3ABC, a precursor of the sole HAV protease, 3C(pro), that is derived by auto-processing of the P3 (3ABCD) segment of the viral polyprotein. Here, we show that HAV also disrupts TLR3 signaling, inhibiting poly(I:C)-stimulated dimerization of IFN regulatory factor 3 (IRF-3), IRF-3 translocation to the nucleus, and IFN-β promoter activation, by targeting TRIF for degradation by a distinct 3ABCD processing intermediate, the 3CD protease-polymerase precursor. TRIF is proteolytically cleaved by 3CD, but not by the mature 3C(pro) protease or the 3ABC precursor that degrades MAVS. 3CD-mediated degradation of TRIF depends on both the cysteine protease activity of 3C(pro) and downstream 3D(pol) sequence, but not 3D(pol) polymerase activity. Cleavage occurs at two non-canonical 3C(pro) recognition sequences in TRIF, and involves a hierarchical process in which primary cleavage at Gln-554 is a prerequisite for scission at Gln-190. The results of mutational studies indicate that 3D(pol) sequence modulates the substrate specificity of the upstream 3C(pro) protease when fused to it in cis in 3CD, allowing 3CD to target cleavage sites not normally recognized by 3C(pro). HAV thus disrupts both RIG-I/MDA5 and TLR3 signaling pathways through cleavage of essential adaptor proteins by two distinct protease precursors derived from the common 3ABCD polyprotein processing intermediate.
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Affiliation(s)
- Lin Qu
- Lineberger Comprehensive Cancer Center and the Division of Infectious Diseases, Department of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Zongdi Feng
- Lineberger Comprehensive Cancer Center and the Division of Infectious Diseases, Department of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Daisuke Yamane
- Lineberger Comprehensive Cancer Center and the Division of Infectious Diseases, Department of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Yuqiong Liang
- Lineberger Comprehensive Cancer Center and the Division of Infectious Diseases, Department of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Robert E. Lanford
- Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, Texas, United States of America
| | - Kui Li
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Stanley M. Lemon
- Lineberger Comprehensive Cancer Center and the Division of Infectious Diseases, Department of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
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5
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Insight into poliovirus genome replication and encapsidation obtained from studies of 3B-3C cleavage site mutants. J Virol 2009; 83:9370-87. [PMID: 19587035 DOI: 10.1128/jvi.02076-08] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A poliovirus (PV) mutant (termed GG), which is incapable of producing 3AB, VPg, and 3CD proteins due to a defective cleavage site between the 3B and 3C proteins, replicated, producing 3BC-linked RNA rather than the VPg-linked RNA produced by the wild type (WT). GG PV RNA is quasi-infectious. The yield of infectious GG PV relative to replicated RNA is reduced by almost 5 logs relative to that of WT PV. Proteolytic activity required for polyprotein processing is normal for the GG mutant. 3BC-linked RNA can be encapsidated as efficiently as VPg-linked RNA. However, a step after genome replication but preceding virus assembly that is dependent on 3CD and/or 3AB proteins limits production of infectious GG PV. This step may involve release of replicated genomes from replication complexes. A pseudorevertant (termed EG) partially restored cleavage at the 3B-3C cleavage site. The reduced rate of formation of 3AB and 3CD caused corresponding reductions in the observed rate of genome replication and infectious virus production by EG PV without impacting the final yield of replicated RNA or infectious virus relative to that of WT PV. Using EG PV, we showed that genome replication and encapsidation were distinct steps in the multiplication cycle. Ectopic expression of 3CD protein reversed the genome replication phenotype without alleviating the infectious-virus production phenotype. This is the first report of a trans-complementable function for 3CD for any picornavirus. This observation supports an interaction between 3CD protein and viral and/or host factors that is critical for genome replication, perhaps formation of replication complexes.
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Nakashima N, Nakamura Y. Cleavage sites of the “P3 region” in the nonstructural polyprotein precursor of a dicistrovirus. Arch Virol 2008; 153:1955-60. [DOI: 10.1007/s00705-008-0208-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2008] [Accepted: 08/29/2008] [Indexed: 11/24/2022]
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7
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Rosas MF, Vieira YA, Postigo R, Martín-Acebes MA, Armas-Portela R, Martínez-Salas E, Sobrino F. Susceptibility to viral infection is enhanced by stable expression of 3A or 3AB proteins from foot-and-mouth disease virus. Virology 2008; 380:34-45. [PMID: 18694581 DOI: 10.1016/j.virol.2008.06.040] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Revised: 06/27/2008] [Accepted: 06/28/2008] [Indexed: 11/19/2022]
Abstract
The foot-and-mouth disease virus (FMDV) 3A protein is involved in virulence and host range. A distinguishing feature of FMDV 3B among picornaviruses is that three non-identical copies are encoded in the viral RNA and required for optimal replication in cell culture. Here, we have studied the involvement of the 3AB region on viral infection using constitutive and transient expression systems. BHK-21 stably transformed clones expressed low levels of FMDV 3A or 3A(B) proteins in the cell cytoplasm. Transformed cells stably expressing these proteins did not exhibit inner cellular rearrangements detectable by electron microscope analysis. Upon FMDV infection, clones expressing either 3A alone or 3A(B) proteins showed a significant increase in the percentage of infected cells, the number of plaque forming units and the virus yield. The 3A-enhancing effect was specific for FMDV as no increase in viral multiplication was observed in transformed clones infected with another picornavirus, encephalomyocarditis virus, or the negative-strand RNA virus vesicular stomatitis virus. A potential role of 3A protein in viral RNA translation was discarded by the lack of effect on FMDV IRES-dependent translation. Increased viral susceptibility was not caused by a released factor; neither the supernatant of transformed clones nor the addition of purified 3A protein to the infection medium was responsible for this effect. Unlike stable expression, high levels of 3A or 3A(B) protein transient expression led to unspecific inhibition of viral infection. Therefore, the effect observed on viral yield, which inversely correlated with the intracellular levels of 3A protein, suggests a transacting role operating on the FMDV multiplication cycle.
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Affiliation(s)
- María F Rosas
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain
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8
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Zhang B, Morace G, Gauss-Müller V, Kusov Y. Poly(A) binding protein, C-terminally truncated by the hepatitis A virus proteinase 3C, inhibits viral translation. Nucleic Acids Res 2007; 35:5975-84. [PMID: 17726047 PMCID: PMC2034478 DOI: 10.1093/nar/gkm645] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2007] [Revised: 08/02/2007] [Accepted: 08/03/2007] [Indexed: 12/30/2022] Open
Abstract
Proteolytic cleavage of translation initiation factors is a means to interfere with mRNA circularization and to induce translation arrest during picornaviral replication or apoptosis. It was shown that the regulated cleavages of eukaryotic initiation factor (eIF) 4G and poly(A)-binding protein (PABP) by viral proteinases correlated with early and late arrest of host cap-dependent and viral internal ribosome entry site (IRES)-dependent translation, respectively. Here we show that in contrast to coxsackievirus, eIF4G is not a substrate of proteinase 3C of hepatitis A virus (HAV 3C(pro)). However, PABP is cleaved by HAV 3C(pro) in vitro and in vivo, separating the N-terminal RNA-binding domain (NTD) of PABP from the C-terminal protein-interaction domain. In vitro, NTD has a dominant negative effect on HAV IRES-dependent translation and an enhanced binding affinity to the RNA structural element pY1 in the 5' nontranslated region of the HAV RNA that is essential for viral genome replication. The results point to a regulatory role of PABP cleavage in RNA template switching of viral translation to RNA synthesis.
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Affiliation(s)
- Bo Zhang
- Institute of Medical Molecular Biology, University of Lübeck, Germany and Istituto Superiore di Sanita, Rome, Italy
| | - Graziella Morace
- Institute of Medical Molecular Biology, University of Lübeck, Germany and Istituto Superiore di Sanita, Rome, Italy
| | - Verena Gauss-Müller
- Institute of Medical Molecular Biology, University of Lübeck, Germany and Istituto Superiore di Sanita, Rome, Italy
| | - Yuri Kusov
- Institute of Medical Molecular Biology, University of Lübeck, Germany and Istituto Superiore di Sanita, Rome, Italy
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9
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Kusov Y, Gauss-Müller V, Morace G. Immunogenic epitopes on the surface of the hepatitis A virus capsid: Impact of secondary structure and/or isoelectric point on chimeric virus assembly. Virus Res 2007; 130:296-302. [PMID: 17640757 DOI: 10.1016/j.virusres.2007.06.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2007] [Revised: 06/07/2007] [Accepted: 06/08/2007] [Indexed: 11/17/2022]
Abstract
Hepatitis A virus (HAV) protein 2A has the capacity to harbor and expose a short foreign epitope. The chimeric virus, HAV-gp41, bearing seven amino acids of the 2F5 epitope of the HIV glycoprotein gp41, was shown to replicate in cell culture and laboratory animals and to induce a humoral immune response. As an extension of this work, we now investigated the possibility to insert longer epitopes, their impact on genetic stability, and the production of chimeric HAV. Twenty-seven amino acid residues of either HIV gp41, comprising the 2F5 epitope, or of a mimotope (F78) of the hypervariable region 1 of the hepatitis C virus (HCV) envelope protein E2 were inserted near the C-terminus of HAV 2A and viral capsid formation and replication were studied. The genome of the chimeric virus (HAV-F78) had reduced replication ability, yet the sedimentation profile of the chimeric particles was unchanged and the HCV sequence was maintained over serial viral passages. In contrast, no capsids were formed when an extended HIV epitope of 27 residues was inserted, precluding the rescue of infectious chimeric virus. Based on structural analyses, the data suggest that the isoelectric point (pI) and/or the secondary structure of the chimeric proteins are essential determinants that affect HAV particle formation for which protein 2A serves as an assembly signal.
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Affiliation(s)
- Yuri Kusov
- Institute of Medical Molecular Biology, University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
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10
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Kusov Y, Kanda T, Palmenberg A, Sgro JY, Gauss-Müller V. Silencing of hepatitis A virus infection by small interfering RNAs. J Virol 2007; 80:5599-610. [PMID: 16699041 PMCID: PMC1472172 DOI: 10.1128/jvi.01773-05] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Infection by hepatitis A virus (HAV) can cause acute hepatitis and, rarely, fulminant liver failure, in particular in patients chronically infected with hepatitis C virus. Based on our previous observation that small interfering RNAs (siRNAs) can silence translation and replication of the firefly luciferase-encoding HAV replicon, we now exploited this technology to demonstrate the effect of siRNAs on viral infection in Huh-7 cells. Freshly and persistently infected cells were transfected with siRNAs targeting various sites in the HAV nonstructural genes. Compared to a single application, consecutive siRNA transfections targeting multiple sequences in the viral genome resulted in a more efficient and sustained silencing effect than a single transfection. In most instances, multiple applications of a single siRNA led to the emergence of viral escape mutants with mutated target sites that rendered these genomes resistant to RNA interference (RNAi). Efficient and sustained suppression of the viral infectivity was achieved after consecutive applications of an siRNA targeting a computer-predicted hairpin structure. This siRNA holds promise as a therapeutic tool for severe courses of HAV infection. In addition, the results provide new insight into the structural bases for sequence-specific RNAi.
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Affiliation(s)
- Yuri Kusov
- Institute of Medical Molecular Biology, University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany.
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11
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Kusov YY, Zamjatina NA, Poleschuk VF, Michailov MI, Morace G, Eberle J, Gauss-Müller V. Immunogenicity of a chimeric hepatitis A virus (HAV) carrying the HIV gp41 epitope 2F5. Antiviral Res 2006; 73:101-11. [PMID: 17014915 DOI: 10.1016/j.antiviral.2006.08.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2006] [Revised: 06/27/2006] [Accepted: 08/04/2006] [Indexed: 10/24/2022]
Abstract
Its stable particle structure combined with its high immunogenicity makes the hepatitis A virus (HAV) a perfect carrier to expose foreign epitopes to the host immune system. In an earlier report [Beneduce, F., Kusov, Y., Klinger, M., Gauss-Müller, V., Morace, G., 2002. Chimeric hepatitis A virus particles presenting a foreign epitope (HIV gp41) at their surface. Antiviral Res. 55, 369-377] chimeric virus-like particles (HAV-gp41) were described that carried at their surface the dominant gp41 epitope 2F5 (2F5e) of the human immunodeficiency virus HIV-1. Extending this work, we now report that chimeric virus HAV-gp41 replicates in HAV-susceptible cells as well as in non-human primates. Infected marmosets developed both an anti-HAV and anti-2F5 epitope immune response. Furthermore, an HIV-neutralizing antibody response was elicited in guinea pigs immunized with HAV-gp41 chimeric particles. The results demonstrate that the replication-competent chimeric HAV-gp41 can serve as either a live or a subunit vaccine for eliciting of antibodies directed against a foreign antigenic epitope.
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Affiliation(s)
- Yuri Y Kusov
- Institute of Medical Molecular Biology, University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany.
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12
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Peters H, Kusov Y, Meyer S, Benie A, Bäuml E, Wolff M, Rademacher C, Peters T, Gauss-Müller V. Hepatitis A virus proteinase 3C binding to viral RNA: correlation with substrate binding and enzyme dimerization. Biochem J 2005; 385:363-70. [PMID: 15361063 PMCID: PMC1134706 DOI: 10.1042/bj20041153] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Proteinase 3C of hepatitis A virus (HAV) plays a key role in the viral life cycle by generating mature viral proteins from the precursor polyprotein. In addition to its proteolytic activity, 3C binds to viral RNA, and thus influences viral genome replication. In order to investigate the interplay between proteolytic activity and RNA binding at the molecular level, we subjected HAV 3C and three variants carrying mutations of the cysteine residues [C24S (Cys-24-->Ser), C172A and C24S/C172A] to proteolysis assays with peptide substrates, and to surface plasmon resonance binding studies with peptides and viral RNA. We report that the enzyme readily forms dimers via disulphide bridges involving Cys-24. Dissociation constants (K(D)) for peptides were in the millimolar range. The binding kinetics for the peptides were characterized by k(on) and k(off) values of the order of 10(2) M(-1) x s(-1) and 10(-2) to 10(-1) s(-1) respectively. In contrast, 3C binding to immobilized viral RNA, representing the structure of the 5'-terminal domain, followed fast binding kinetics with k(on) and k(off) values beyond the limits of the kinetic resolution of the technique. The affinity of viral RNA depended strongly on the dimerization status of 3C. Whereas monomeric 3C bound to the viral RNA with a K(D) in the millimolar range, dimeric 3C had a significantly increased binding affinity with K(D) values in the micromolar range. A model of the 3C dimer suggests that spatial proximity of the presumed RNA-binding motifs KFRDI is possible. 3C binding to RNA was also promoted in the presence of substrate peptides, indicating co-operativity between RNA binding and protease activity. The data imply that the dual functions of 3C are mutually dependent, and regulate protein and RNA synthesis during the viral life cycle.
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Affiliation(s)
- Hannelore Peters
- *Institute of Chemistry, University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
| | - Yuri Y. Kusov
- †Institute of Medical Molecular Biology, University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
| | - Sonja Meyer
- *Institute of Chemistry, University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
| | - Andrew J. Benie
- *Institute of Chemistry, University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
| | - Englbert Bäuml
- *Institute of Chemistry, University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
| | - Maike Wolff
- *Institute of Chemistry, University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
| | - Christoph Rademacher
- *Institute of Chemistry, University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
| | - Thomas Peters
- *Institute of Chemistry, University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
- To whom correspondence should be addressed (email )
| | - Verena Gauss-Müller
- †Institute of Medical Molecular Biology, University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
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13
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Harris JR, Racaniello VR. Amino acid changes in proteins 2B and 3A mediate rhinovirus type 39 growth in mouse cells. J Virol 2005; 79:5363-73. [PMID: 15827151 PMCID: PMC1082767 DOI: 10.1128/jvi.79.9.5363-5373.2005] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Many steps of viral replication are dependent on the interaction of viral proteins with host cell components. To identify rhinovirus proteins involved in such interactions, human rhinovirus 39 (HRV39), a virus unable to replicate in mouse cells, was adapted to efficient growth in mouse cells producing the viral receptor ICAM-1 (ICAM-L cells). Amino acid changes were identified in the 2B and 3A proteins of the adapted virus, RV39/L. Changes in 2B were sufficient to permit viral growth in mouse cells; however, changes in both 2B and 3A were required for maximal viral RNA synthesis in mouse cells. Examination of infected HeLa cells by electron microscopy demonstrated that human rhinoviruses induced the formation of cytoplasmic membranous vesicles, similar to those observed in cells infected with other picornaviruses. Vesicles were also observed in the cytoplasm of HRV39-infected mouse cells despite the absence of viral RNA replication. Synthesis of picornaviral nonstructural proteins 2C, 2BC, and 3A is known to be required for formation of membranous vesicles. We suggest that productive HRV39 infection is blocked in ICAM-L cells at a step posttranslation and prior to the formation of a functional replication complex. The observation that changes in HRV39 2B and 3A proteins lead to viral growth in mouse cells suggests that one or both of these proteins interact with host cell proteins to promote viral replication.
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Affiliation(s)
- Julie R Harris
- Department of Microbiology, Columbia University College of Physicians & Surgeons, 701 W. 168th St., New York, NY 10032, USA
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14
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Kusov YY, Gosert R, Gauss-Müller V. Replication and in vivo repair of the hepatitis A virus genome lacking the poly(A) tail. J Gen Virol 2005; 86:1363-1368. [PMID: 15831948 DOI: 10.1099/vir.0.80644-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The precise role of the poly(A) tail at the 3' end of the picornavirus RNA genome and the cellular factors that control its homeostasis are unknown. To assess the importance of the poly(A) tail for virus replication, the genome of the slowly replicating hepatitis A virus (HAV) with and without a poly(A) tail was studied after transfection into cells maintained under various conditions. A tailless HAV genome had a shorter half-life than a poly(A)-containing genome and was unable to replicate in quiescent cells. In dividing cells, the tailless RNA gave rise to infectious virus with a restored poly(A) tail of up to 60 residues. Cells arrested at the G(0) and the G(2)/M phase produced lower amounts of infectious HAV than cells in the G(1) phase. These data suggest that the 3' poly(A) tail of HAV can be restored with the help of a cellular and/or viral function that is regulated during the cell cycle.
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Affiliation(s)
- Yuri Y Kusov
- Department of Medical Molecular Biology, University of Lübeck, Ratzeburger Allee 160, D-23562 Lübeck, Germany
| | - Rainer Gosert
- Department of Medical Microbiology, Department of Virology, Basel, Switzerland
| | - Verena Gauss-Müller
- Department of Medical Molecular Biology, University of Lübeck, Ratzeburger Allee 160, D-23562 Lübeck, Germany
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15
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Rachow A, Gauss-Müller V, Probst C. Homogeneous hepatitis A virus particles. Proteolytic release of the assembly signal 2A from procapsids by factor Xa. J Biol Chem 2003; 278:29744-51. [PMID: 12782637 DOI: 10.1074/jbc.m300454200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Among the picornaviridae, hepatitis A virus (HAV) is unique in that its assembly is driven by domain 2A of P1-2A, the precursor of the structural proteins (Probst, C., Jecht, M., and Gauss-Müller, V. (1999) J. Biol. Chem. 274, 4527-4531). Whereas infected individuals excrete in stool mature HAV capsids with VP1 as the major structural protein, its C-terminal extended form VP1-2A is the main component of immature procapsids produced in HAV-infected cells in culture. Obviously, a postassembly proteolytic step is required to remove the primary assembly signal 2A from VP1-2A of procapsids. Mutants of VP1-2A were expressed in COS7 cells to determine the cleavage site in VP1-2A and to test for the cleavage potential of viral and host proteinases (factor Xa and thrombin). Site-specific in vitro cleavage by factor Xa and thrombin occurred in procapsids that contained VP1-2A with engineered cognate cleavage sites for these proteinases. Interestingly, factor Xa but not thrombin liberated mature VP1 also from native procapsids in an assembly-dependent manner. The data show that domain 2A, which is required for pentamerization of its precursor polypeptides and thus for the primary step of HAV assembly, is removed from the surface of immature procapsid by a host proteinase. Moreover, our data open a novel avenue to produce homogeneous HAV particles from recombinant intermediates by in vitro treatment with exogenously added proteases such as factor Xa or thrombin.
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Affiliation(s)
- Andrea Rachow
- Institute of Medical Molecular Biology, University of Luebeck, 23538 Luebeck, Germany
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16
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Kanda T, Yokosuka O, Kato N, Imazeki F, Fujiwara K, Kawai S, Saisho H, Omata M. Hepatitis A virus VP3 may activate serum response element associated transcription. Scand J Gastroenterol 2003; 38:307-13. [PMID: 12737447 DOI: 10.1080/00365520310000654a] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Hepatitis A virus (HAV) infection is a major public health problem worldwide. The infection does not induce any visible cytopathic effects or interfere with macromolecular synthesis in host cells. However, the hepatitis B and C viruses have recently been reported to activate intracellular signals. To clarify the effects of HAV infection on intracellular signalling, we examined the influence of 9 FLAG-tagged HAV proteins (VP2, VP3, VP1-2A, 2B, 2C, 3A, 3BC, 3C and 3D) on signal transduction pathways. METHODS Viral protein expression vectors were co-transfected into HeLa cells with reporter plasmids controlled by a synthetic promoter containing direct repeats of the cyclic AMP response element (CRE), serum response factor (SRF), activator protein 1 (AP-1), nuclear factor kappaB (NF-kappaB) or serum response element (SRE). Cells were harvested 42 h after transfection and luciferase assays were performed. Viral protein activation twice that of the control was defined as significant. RESULTS VP3 induced an SRE-associated signal 2.2 +/- 0.3 times higher than that of control. VP3 did not activate CRE-, SRF-, AP-1- or NF-kappaB- associated signalling. The other HAV proteins tested also failed to induce these pathways. CONCLUSIONS HAV interacts with the host signalling mechanism, and HAV VP3, different from HBX and hepatitis C core protein, may activate only SRE-associated intracellular signalling, a pathway associated with cell proliferation and differentiation.
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Affiliation(s)
- T Kanda
- Dept. of Medicine and Clinical Oncology, Graduate School of Medicine, Chiba University, Chiba, Japan
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17
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Han S, Sanfaçon H. Tomato ringspot virus proteins containing the nucleoside triphosphate binding domain are transmembrane proteins that associate with the endoplasmic reticulum and cofractionate with replication complexes. J Virol 2003; 77:523-34. [PMID: 12477857 PMCID: PMC140641 DOI: 10.1128/jvi.77.1.523-534.2003] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Replication of all known positive-strand RNA viruses occurs in replication complexes associated with intracellular membranes. The putative nucleoside triphosphate binding (NTB) protein of Tomato ringspot virus (ToRSV) contains a stretch of hydrophobic residues at its C terminus, suggesting that it may act as a membrane anchor for the replication complex. Anti-NTB antibodies detected two predominant proteins in membrane-enriched fractions (the 66-kDa NTB and 69-kDa NTB-VPg proteins) along with other, larger proteins. The proteins containing the NTB domain cofractionated with markers of the endoplasmic reticulum (ER) and with ToRSV-specific RNA-dependent RNA polymerase activity in sucrose gradients. ToRSV infection induced severe changes in the morphology of the ER in plants expressing an ER-targeted green fluorescent protein (ER-GFP), and proteins containing the NTB domain colocalized with ER-GFP in indirect immunofluorescence assays. The proteins containing the NTB domain have properties of integral membrane proteins. Proteinase K protection assays using purified membranes from infected plants revealed that although the central portion of the NTB domain is exposed to the cytoplasmic face of the membranes, an 8-kDa fragment, recognized by anti-VPg antibodies, is protected by the membranes. This fragment probably consists of the 3-kDa VPg and the 5-kDa stretch of hydrophobic residues at the C terminus of the NTB protein, suggesting a luminal location for the VPg in at least a portion of the molecules. These results provide evidence that proteins containing the NTB domain are transmembrane proteins associated with ER-derived membranes and support the hypothesis that one or several of the proteins containing the NTB domain anchor the replication complex to the ER.
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Affiliation(s)
- Sumin Han
- Department of Botany, University of British Columbia, Vancouver, Canada
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18
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Capozzo AVE, Burke DJ, Fox JW, Bergmann IE, La Torre JL, Grigera PR. Expression of foot and mouth disease virus non-structural polypeptide 3ABC induces histone H3 cleavage in BHK21 cells. Virus Res 2002; 90:91-9. [PMID: 12457965 DOI: 10.1016/s0168-1702(02)00140-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Auto-processing of the non-structural polypeptide 3ABC of foot and mouth disease virus (FMDV) expressed in Escherichia coli-BL21-DE3 was prevented by mutating either four glutamic acid residues at the 3A/3B1, 3B1/2, 3B2/3 and 3B3/3C junctions (3ABCtet) or a single cysteine residue at position 383 within the 3C domain (3ABCm). Independent expression of 3ABC and 3ABCtet genes induced expression of chaperone DnaK and degradation of ribosomal S1 protein in E. coli. They also induced cleavage of nucleosomal histone H3 when transiently expressed in BHK21 cells. 3ABCtet, 3ABCm, 3AB and 3A proteins concentrated in the perinuclear region suggesting that peptide sequences within the 3A domain specify intracellular targeting of 3ABC in BHK-21 cells. We propose that 3ABC molecules localized in the nuclear periphery are a source of protease 3C activity and are responsible for histone H3 processing during FMDV infections.
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Affiliation(s)
- A V E Capozzo
- Centro de Virologia Animal (CEVAN-CONICET), Serrano 669, Ciudad de Buenos Aires, 1414 Capital Federa, Buenos Aires, Argentina
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19
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Kusov YY, Shatirishvili G, Klinger M, Gauss-Müller V. A vaccinia virus MVA-T7-mediated recovery of infectious hepatitis A virus from full-size cDNA or from two cDNAs, both by themselves unable to complete the virus life cycle. Virus Res 2002; 89:75-88. [PMID: 12367752 DOI: 10.1016/s0168-1702(02)00115-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The replication-deficient vaccinia virus (VV) MVA-T7 produces large amounts of T7 RNA polymerase and permits efficient protein expression from cDNA of T7-promoted genes. Yet, unlike recombinant VV vTF7-3, (VV) MVA-T7 produces no cytopathic effect in primate cells, thus allowing the study of processes with slow kinetics. We have applied MVA-T7 to aid genome expression of HAV, a representative of the Picornaviridae family that is well known for its inefficient replication in mammalian cell cultures. After cDNA transfection and MVA-T7 infection, empty capsids and mature HAV particles were formed with different kinetics and were characterized by their morphology, protein content, and infectivity. The data suggests that HAV genome replication is initiated from RNA, which was transcribed in vivo by the MVA-T7-encoded T7 RNA polymerase. HAV genome replication was also demonstrated in a recombination assay. After co-expression of two subgenomic HAV cDNAs, both by themselves unable to complete the viral life cycle, infectious HAV was rescued, indicating that replication-dependent genetic recombination has occurred. We propose that the high-level genome expression mediated in vivo by the VV-encoded T7 RNA polymerase augments the amount of viral RNA, such that replication of viruses poorly replicating in cell cytoplasm is detectable.
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Affiliation(s)
- Yuri Y Kusov
- Institute of Medical Molecular Biology, Medical University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany.
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20
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Gauss-Müller V, Kusov YY. Replication of a hepatitis A virus replicon detected by genetic recombination in vivo. J Gen Virol 2002; 83:2183-2192. [PMID: 12185272 DOI: 10.1099/0022-1317-83-9-2183] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Unlike other picornaviruses, hepatitis A virus (HAV) replicates so inefficiently in cell culture that the study of its RNA biosynthesis presents a major experimental challenge. To assess viral RNA replication independent of particle formation, a subgenomic replicon representing a self-replicating RNA was constructed by replacing the P1 domain encoding the capsid proteins with the firefly luciferase sequence. Although translation of the HAV replicon was as efficient as a similar poliovirus replicon, the luciferase activity derived from replication of the HAV construct was more than 100-fold lower than that of poliovirus. The replication capacity of the HAV replicon was clearly demonstrated by its ability to recombine genetically with a non-viable, full-length HAV genome that served as capsid donor and thus to rescue a fully infectious virus. In contrast to a replication-deficient replicon, co-expression of the genetically marked and replication-competent HAV replicon with several lethally mutated HAV genomes resulted in the successful rescue of infectious HAV with a unique genetic marker. Our data suggest: (i) that autonomous HAV RNA replication does not require sequences for the HAV structural proteins; and (ii) that low-level genome replication can unequivocally be demonstrated by the rescue of infectious virus after co-expression with non-viable genomes.
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Affiliation(s)
- Verena Gauss-Müller
- Institute of Medical Molecular Biology, Medical University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany1
| | - Yuri Y Kusov
- Institute of Medical Molecular Biology, Medical University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany1
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21
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Beneduce F, Kusov Y, Klinger M, Gauss-Müller V, Morace G. Chimeric hepatitis A virus particles presenting a foreign epitope (HIV gp41) at their surface. Antiviral Res 2002; 55:369-77. [PMID: 12103436 DOI: 10.1016/s0166-3542(02)00073-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hepatitis A virus (HAV) protein 2A has been demonstrated to be involved in virus morphogenesis and suggested to be located on the surface of the particle. To determine whether this protein can function as a target structure to harbor and expose foreign epitopes on HAV particles, a full-length HAV cDNA, containing a seven amino acid stretch of human immunodeficiency virus type 1 (HIV-1) envelope protein gp41, was constructed. Following vaccinia virus MVA-T7-mediated expression of the cDNA in COS7 and Huh-T7 cells, chimeric HAV particles, exposing the foreign epitope gp41 on their surface, were produced. These particles were found to be empty capsids (70S), as judged by immunospecific enzyme linked immunosorbent assay (ELISA) on sucrose gradient fractions and immunoelectron microscopy. The immunological detection of VP1-2A harboring the gp41 epitope of HIV suggests that the 2A domain of HAV is suitable to present foreign antigenic epitopes.
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Affiliation(s)
- Francesca Beneduce
- Laboratory of Virology, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy
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22
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Affiliation(s)
- E Sadowy
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
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23
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Pintó RM, Guix S, González-Dankaart JF, Caballero S, Sánchez G, Guo KJ, Ribes E, Bosch A. Hepatitis A virus polyprotein processing by Escherichia coli proteases. J Gen Virol 2002; 83:359-368. [PMID: 11807229 DOI: 10.1099/0022-1317-83-2-359] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Hepatitis A virus (HAV) encodes a single polyprotein, which is post-translationally processed. This processing represents an essential step in capsid formation. The virus possesses only one protease, 3C, responsible for all cleavages, except for that at the VP1/2A junction region, which is processed by cellular proteases. In this study, data demonstrates that HAV polyprotein processing by Escherichia coli protease(s) leads to the formation of particulate structures. P3 polyprotein processing in E. coli is not dependent on an active 3C protease: the same processing pattern is observed with wild-type 3C or with several 3C mutants. However, this processing pattern is temperature-dependent, since it differs at 37 or 42 degrees C. The bacterial protease(s) cleave scissile bonds other than those of HAV; this contributes to the low efficiency of particle formation.
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Affiliation(s)
- Rosa M Pintó
- Department of Microbiology1 and Department of Animal and Plant Cell Biology2, University of Barcelona, Av. Diagonal 645, 08028 Barcelona, Spain
| | - Susana Guix
- Department of Microbiology1 and Department of Animal and Plant Cell Biology2, University of Barcelona, Av. Diagonal 645, 08028 Barcelona, Spain
| | - Juan F González-Dankaart
- Department of Microbiology1 and Department of Animal and Plant Cell Biology2, University of Barcelona, Av. Diagonal 645, 08028 Barcelona, Spain
| | - Santiago Caballero
- Department of Microbiology1 and Department of Animal and Plant Cell Biology2, University of Barcelona, Av. Diagonal 645, 08028 Barcelona, Spain
| | - Gloria Sánchez
- Department of Microbiology1 and Department of Animal and Plant Cell Biology2, University of Barcelona, Av. Diagonal 645, 08028 Barcelona, Spain
| | - Ke-Jian Guo
- Department of Microbiology1 and Department of Animal and Plant Cell Biology2, University of Barcelona, Av. Diagonal 645, 08028 Barcelona, Spain
| | - Enric Ribes
- Department of Microbiology1 and Department of Animal and Plant Cell Biology2, University of Barcelona, Av. Diagonal 645, 08028 Barcelona, Spain
| | - Albert Bosch
- Department of Microbiology1 and Department of Animal and Plant Cell Biology2, University of Barcelona, Av. Diagonal 645, 08028 Barcelona, Spain
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Kusov YY, Shatirishvili G, Dzagurov G, Gauss-Müller V. A new G-tailing method for the determination of the poly(A) tail length applied to hepatitis A virus RNA. Nucleic Acids Res 2001; 29:E57-7. [PMID: 11410680 PMCID: PMC55756 DOI: 10.1093/nar/29.12.e57] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
To study the role of the poly(A) tail length during the replication of poly(A)-containing plus-strand RNA virus, we have developed a simple reverse transcription polymerase chain reaction (RT-PCR)-based method that substantially improves the previously reported PAT [poly(A) test] assay. In contrast to the PAT assay, the new method is based on the enzymatic 3' elongation of mRNA with guanosine residues, thus immediately preserving the 3' end of the RNA and creating a unique poly(A)-oligo(G) junction. The oligo(G)-protected full-length poly(A) tail is reverse transcribed using the universal anti-sense primer oligo(dC(9)T(6)) and amplified by PCR with a gene-specific sense primer. After sequencing the resulting RT-PCR product the length of the poly(A) tail was unequivocally deduced from the number of adenosine residues between the oligo(G) stretch and the sequence upstream of the poly(A) tail. The efficiency and specificity of the newly developed assay was demonstrated by analysing the poly(A) tail length of the hepatitis A virus (HAV) RNA. We show here that the poly(A) tail of HAV RNA rescued after transfection of in vitro transcripts was elongated in the course of HAV replication.
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Affiliation(s)
- Y Y Kusov
- Institute of Medical Molecular Biology, Medical University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany.
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