Evidence that the Genomic RNA of Hepatitis E Virus Is Capped

Kabrane-Lazizi, Yamina; Meng, Xiang‐Jin; Purcell, Robert H.; Emerson, Suzanne U.

doi:10.1128/jvi.73.10.8848-8850.1999

Cited by 125 publications

(45 citation statements)

References 14 publications

(14 reference statements)

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“…The HEV genome encodes a domain of methyltransferase that functions as a virus-specific mRNA capping enzyme, and this domain is known to be a crucial requirement for the infectivity. (31,32) However, G5 HEV was unexpectedly recovered from the cell culture supernatants by transfection with uncapped G5 HEV, demonstrating that the cap structure is not absolutely required for the initiation of viral replication. Nonetheless, the longer lag phase after transfection of the uncapped RNA, which extended the incubation for 36 days, suggested that the 5′-cap structure strongly affected the efficiency of the G5 HEV replication.…”

Section: Discussionmentioning

confidence: 99%

Genotype 5 Hepatitis E Virus Produced by a Reverse Genetics System Has the Potential for Zoonotic Infection

Bai

Yoshizaki

et al. 2018

Hepatol Commun

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Neither an animal model nor a cell culture system has been established for the genotype 5 hepatitis E virus (G5 HEV), and the pathogenicity, epidemiology, and replication mechanism of the virus remain unclear. In this study, we used a reverse genetics system to generate G5 HEV and examined the possibility of zoonotic infection. Capped and uncapped genomic G5 HEV RNAs generated by in vitro transcription were transfected into PLC/PRF/5 cells. Infectious G5 HEV was recovered from the capped G5 HEV RNA–transfected PLC/PRF/5 cells and the subsequently passaged cells. G5 HEV was also recovered from uncapped G5 HEV–transfected PLC/PRF/5 cells after a longer lag phase, suggesting that the 5′‐cap structure is not essential but affected the efficiency of G5 HEV replication. G5 HEV infection was neutralized not only by anti‐G5 HEV‐like particles (HEV‐LPs) antibody, but also by anti‐G1, anti‐G3, anti‐G4, and anti‐G7 HEV‐LPs antibodies. G5 HEV was capable of infecting cynomolgus monkeys negative for anti‐HEV antibody but not animals positive for anti‐G7 HEV immunoglobulin G (IgG), indicating that cynomolgus monkeys were susceptible to G5 HEV, and the serotype of G5 HEV was identical to that of G7 HEV and human HEVs. Moreover, G5 HEV replication was efficiently inhibited by ribavirin and partially inhibited by sofosbuvir. Conclusion: Infectious G5 HEV was produced using a reverse genetics system, and the antigenicity was identical to that of human HEVs and G7 HEV. Transmission of G5 HEV to primates was confirmed by an experimental infection, providing evidence of the possibility of zoonotic infection by G5 HEV.

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Section: Discussionmentioning

confidence: 99%

Genotype 5 Hepatitis E Virus Produced by a Reverse Genetics System Has the Potential for Zoonotic Infection

Bai

Yoshizaki

et al. 2018

Hepatol Commun

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“…Immunoprecipitation of RNAs with anti-cap MAb. Immunoprecipitation of RNAs with anti-cap MAb was performed as previously described (28). Briefly, H20, a specific anti-cap MAb, was incubated with protein G-Sepharose beads for 1 h at 4°C, and then the beads were washed three times with binding buffer (10 mM Tris base, 150 mM NaCl, 10 mM EDTA, pH 7.5).…”

Section: Methodsmentioning

confidence: 99%

VP1 and VP3 Are Required and Sufficient for Translation Initiation of Uncapped Infectious Bursal Disease Virus Genomic Double-Stranded RNA

Wang

Zhang

et al. 2018

J Virol

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Infectious bursal disease virus (IBDV) is a bi-segmented double-strand RNA (dsRNA) virus of the family. While IBDV genomic dsRNA lacks a 5' cap, the means by which the uncapped IBDV genomic RNA is translated effectively is unknown. In this study, we describe a cap-independent pathway of translation initiation of IBDV uncapped RNA that relies on VP1 and VP3. We show that neither purified IBDV genomic dsRNA nor the uncapped viral plus-sense RNA transcripts was directly translated and rescued into infectious viruses in host cells. This defect in translation of the uncapped IBDV genomic dsRNA was rescued by-supplementation of the viral proteins VP1 and VP3, which was dependent on both the intact polymerase activity of VP1 and the dsRNA binding activity of VP3. Deletion analysis showed that both 5' - and 3' -UTRs of IBDV dsRNA were essential for the VP1/VP3-dependent translation initiation. Significantly, VP1 and VP3 could also mediate the recovery of infectious IBDV from the authentic minus-sense strand of IBDV dsRNA. Moreover, down-regulation or inhibition of the cap-binding protein eIF4E did not decrease, but rather enhanced the VP1/VP3-mediated translation of the uncapped IBDV RNA. Collectively, our findings for the first time reveal that VP1 and VP3 compensate for the deficiency of 5' cap and replace eIF4E to confer upon the uncapped IBDV RNA the ability to be translated and rescued into infectious viruses.A key point of control for virus replication is the viral translation initiation. The current study shows that the uncapped IBDV RNA cannot be translated into viral proteins directly by host translation machinery, and is thus noninfectious. Our results constitute the first direct experimental evidence that the VP1 and VP3 are required and sufficient to initiate translation of uncapped IBDV genomic RNA by acting as a substitute of cap and replacing the cap-binding protein eIF4E. Significantly, the VP1/VP3 mediate the recovery of infectious IBDV not only from the plus-sense but also from the minus-sense strand of the IBDV dsRNA. These findings provide not only new insights into the molecular mechanisms of the life cycle of IBDV, but also a new tool for an alternative strategy for the recovery of IBDV from both the plus- and the minus-sense strand of the viral genomic dsRNA.

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“…The genome of HEV contains three ORFs, a 5′ non‐coding region (NCR) and a 3′ NCR. Open reading frame‐1 encodes a non‐structural polypeptide protein containing several functional domains and motifs such as the methyl transferase (Kabrane‐Lazizi et al., 1999; Magden et al., 2001), a putative papain‐like cystein protease (Ahmad et al., 2011), a dispensable hypervariable region (Pudupakam et al., 2009, 2011), a helicase (Karpe and Lole, 2010a,b) and an RNA‐dependent RNA polymerase (Ahmad et al., 2011). Open reading frame‐2 encodes the immunogenic Cap (Schofield et al., 2003).…”

Section: Swine Hepatitis E Virusmentioning

confidence: 99%

Emerging and Re-emerging Swine Viruses

Meng

2012

Transboundary and Emerging Diseases

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Summary In the past two decades or so, a number of viruses have emerged in the global swine population. Some, such as porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2), cause economically important diseases in pigs, whereas others such as porcine torque teno virus (TTV), now known as Torque teno sus virus (TTSuV), porcine bocavirus (PBoV) and related novel parvoviruses, porcine kobuvirus, porcine toroviruses (PToV) and porcine lymphotropic herpesviruses (PLHV), are mostly subclinical in swine herds. Although some emerging swine viruses such as swine hepatitis E virus (swine HEV), porcine endogenous retrovirus (PERV) and porcine sapovirus (porcine SaV) may have a limited clinical implication in swine health, they do pose a potential public health concern in humans due to zoonotic (swine HEV) or potential zoonotic (porcine SaV) and xenozoonotic (PERV, PLHV) risks. Other emerging viruses such as Nipah virus, Bungowannah virus and Menangle virus not only cause diseases in pigs but some also pose important zoonotic threat to humans. This article focuses on emerging and re‐emerging swine viruses that have a limited or uncertain clinical and economic impact on pig health. The transmission, epidemiology and pathogenic potential of these viruses are discussed. In addition, the two economically important emerging viruses, PRRSV and PCV2, are also briefly discussed to identify important knowledge gaps.

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Evidence that the Genomic RNA of Hepatitis E Virus Is Capped

Cited by 125 publications

References 14 publications

Genotype 5 Hepatitis E Virus Produced by a Reverse Genetics System Has the Potential for Zoonotic Infection

Genotype 5 Hepatitis E Virus Produced by a Reverse Genetics System Has the Potential for Zoonotic Infection

VP1 and VP3 Are Required and Sufficient for Translation Initiation of Uncapped Infectious Bursal Disease Virus Genomic Double-Stranded RNA

Emerging and Re-emerging Swine Viruses

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