1
|
Shen S, Liu W, Zeng G, Liang H, Yu X, Zhang H, Sun J, Guo H. Conditional replication and secretion of hepatitis B virus genome uncover the truncated 3' terminus of encapsidated viral pregenomic RNA. J Virol 2023; 97:e0076023. [PMID: 37754759 PMCID: PMC10617516 DOI: 10.1128/jvi.00760-23] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Accepted: 08/07/2023] [Indexed: 09/28/2023] Open
Abstract
IMPORTANCE The biogenesis and clinical application of serum HBV pgRNA have been a research hotspot in recent years. This study further characterized the heterogeneity of the 3' terminus of capsid RNA by utilizing a variety of experimental systems conditionally supporting HBV genome replication and secretion, and reveal that the 3' truncation of capsid pgRNA is catalyzed by cellular ribonuclease(s) and viral RNaseH at positions after and before 3' DR1, respectively, indicating the 3' DR1 as a boundary between the encapsidated portion of pgRNA for reverse transcription and the 3' unprotected terminus, which is independent of pgRNA length and the 3' terminal sequence. Thus, our study provides new insights into the mechanism of pgRNA encapsidation and reverse transcription, as well as the optimization of serum HBV RNA diagnostics.
Collapse
Affiliation(s)
- Sheng Shen
- Department of Infectious Diseases, State Key Laboratory of Organ Failure Research, Key Laboratory of Infectious Diseases Research in South China, Ministry of Education, Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Nanfang Hospital, Southern Medical University, Guangzhou, China
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Cancer Virology Program, UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Wendong Liu
- Department of Infectious Diseases, State Key Laboratory of Organ Failure Research, Key Laboratory of Infectious Diseases Research in South China, Ministry of Education, Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Ge Zeng
- Department of Infectious Diseases, State Key Laboratory of Organ Failure Research, Key Laboratory of Infectious Diseases Research in South China, Ministry of Education, Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Hongyan Liang
- Department of Infectious Diseases, State Key Laboratory of Organ Failure Research, Key Laboratory of Infectious Diseases Research in South China, Ministry of Education, Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xiaoyang Yu
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Cancer Virology Program, UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Hu Zhang
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Cancer Virology Program, UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Jian Sun
- Department of Infectious Diseases, State Key Laboratory of Organ Failure Research, Key Laboratory of Infectious Diseases Research in South China, Ministry of Education, Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Haitao Guo
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Cancer Virology Program, UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| |
Collapse
|
2
|
Evolutional transition of HBV genome during the persistent infection determined by single-molecule real-time sequencing. Hepatol Commun 2023; 7:e0047. [PMID: 36848123 PMCID: PMC9974078 DOI: 10.1097/hc9.0000000000000047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 12/20/2022] [Indexed: 03/01/2023] Open
Abstract
BACKGROUND Although HBV infection is a serious health issue worldwide, the landscape of HBV genome dynamics in the host has not yet been clarified. This study aimed to determine the continuous genome sequence of each HBV clone using a single-molecule real-time sequencing platform, and clarify the dynamics of structural abnormalities during persistent HBV infection without antiviral therapy. PATIENTS AND METHODS Twenty-five serum specimens were collected from 10 untreated HBV-infected patients. Continuous whole-genome sequencing of each clone was performed using a PacBio Sequel sequencer; the relationship between genomic variations and clinical information was analyzed. The diversity and phylogeny of the viral clones with structural variations were also analyzed. RESULTS The whole-genome sequences of 797,352 HBV clones were determined. The deletion was the most common structural abnormality and concentrated in the preS/S and C regions. Hepatitis B e antibody (anti-HBe)-negative samples or samples with high alanine aminotransferase levels have significantly diverse deletions than anti-HBe-positive samples or samples with low alanine aminotransferase levels. Phylogenetic analysis demonstrated that various defective and full-length clones evolve independently and form diverse viral populations. CONCLUSIONS Single-molecule real-time long-read sequencing revealed the dynamics of genomic quasispecies during the natural course of chronic HBV infections. Defective viral clones are prone to emerge under the condition of active hepatitis, and several types of defective variants can evolve independently of the viral clones with the full-length genome.
Collapse
|
3
|
5' preS1 mutations to prevent large envelope protein expression from hepatitis B virus genotype A or genotype D markedly increase polymerase-envelope fusion protein. J Virol 2022; 96:e0172321. [PMID: 35019714 PMCID: PMC8906437 DOI: 10.1128/jvi.01723-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hepatitis B virus (HBV) large (L) envelope protein is translated from 2.4-kb RNA. It contains preS1, preS2, and S domains and is detected in Western blot as p39 and gp42. The 3.5-kb pregenomic RNA produces core and polymerase (P) proteins. We generated L-minus mutants of a genotype A clone and a genotype D clone from 1.1mer or 1.3mer construct, with the former overproducing pregenomic RNA. Surprisingly, mutating preS1 ATG codon(s) or introducing a nonsense mutation soon afterwards switched secreted p39/gp42 into p41/p44 doublet, with its amount further increased by a nonsense mutation in the core gene. A more downstream preS1 nonsense mutation prevented p41/p44 production. Tunicamycin treatment confirmed p44 as glycosylated form of p41. In this regard splicing of 3.5-kb RNA to generate nt2447-nt2902 junction for genotype D enables translation of p43, with N-terminal 47 residues of P protein fused to C-terminal 371 residues of L protein. Indeed p41/p44 were detectable by an antibody against N-terminus of P protein, and eliminated by a nonsense mutation at 5' P gene or a point mutation to prevent that splicing. Therefore, lost L (and core) protein expression from 1.1mer or 1.3mer construct markedly increased p41/p44 (p43), the P-L fusion protein. Co-transfection with an expression construct for L/M proteins reversed high extracellular p41/p44 associated with L-minus mutants, suggesting that L protein retains p43 in wild-type HBV to promote its intracellular degradation. Considering that p43 lacks N-terminal preS1 sequence critical for receptor binding, its physiological significance during natural infection and therapeutic potential warrant further investigation. IMPORTANCE The large (L) envelope protein of hepatitis B virus (HBV) is translated from 2.4-kb RNA and detected in Western blot as p39 and gp42. Polymerase (P) protein is expressed at a low level from 3.5-kb RNA. The major spliced form of 3.5-kb RNA will produce a fusion protein between the first 47 residues of P protein and a short irrelevant sequence, although also at a low level. Another spliced form has the same P protein sequence fused to L protein missing its first 18 residues. We found that some point mutations to eliminate L and core protein expression from overlength HBV DNA constructs converted p39/gp42 into p41/gp44, which turned out to be that P-L fusion protein. Thus, the P-L fusion protein can be expressed at extremely high level when L protein expression is prevented. The underlying mechanism and functional significance of this variant form of L protein warrant further investigation.
Collapse
|
4
|
Kremsdorf D, Lekbaby B, Bablon P, Sotty J, Augustin J, Schnuriger A, Pol J, Soussan P. Alternative splicing of viral transcripts: the dark side of HBV. Gut 2021; 70:2373-2382. [PMID: 34535538 DOI: 10.1136/gutjnl-2021-324554] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 09/06/2021] [Indexed: 02/06/2023]
Abstract
Regulation of alternative splicing is one of the most efficient mechanisms to enlarge the proteomic diversity in eukaryotic organisms. Many viruses hijack the splicing machinery following infection to accomplish their replication cycle. Regarding the HBV, numerous reports have described alternative splicing events of the long viral transcript (pregenomic RNA), which also acts as a template for viral genome replication. Alternative splicing of HBV pregenomic RNAs allows the synthesis of at least 20 spliced variants. In addition, almost all these spliced forms give rise to defective particles, detected in the blood of infected patients. HBV-spliced RNAs have long been unconsidered, probably due to their uneasy detection in comparison to unspliced forms as well as for their dispensable role during viral replication. However, recent data highlighted the relevance of these HBV-spliced variants through (1) the trans-regulation of the alternative splicing of viral transcripts along the course of liver disease; (2) the ability to generate defective particle formation, putative biomarker of the liver disease progression; (3) modulation of viral replication; and (4) their intrinsic propensity to encode for novel viral proteins involved in liver pathogenesis and immune response. Altogether, tricky regulation of HBV alternative splicing may contribute to modulate multiple viral and cellular processes all along the course of HBV-related liver disease.
Collapse
Affiliation(s)
- Dina Kremsdorf
- Institut National de la Santé et de la Recherche Médicale U938, Centre de Recherche de Saint Antoine, Sorbonne Université-Faculté Saint Antoine, Paris, France
| | - Bouchra Lekbaby
- Institut National de la Santé et de la Recherche Médicale U938, Centre de Recherche de Saint Antoine, Sorbonne Université-Faculté Saint Antoine, Paris, France
| | - Pierre Bablon
- Institut National de la Santé et de la Recherche Médicale U938, Centre de Recherche de Saint Antoine, Sorbonne Université-Faculté Saint Antoine, Paris, France
| | - Jules Sotty
- Institut National de la Santé et de la Recherche Médicale U938, Centre de Recherche de Saint Antoine, Sorbonne Université-Faculté Saint Antoine, Paris, France
| | - Jérémy Augustin
- Institut National de la Santé et de la Recherche Médicale U938, Centre de Recherche de Saint Antoine, Sorbonne Université-Faculté Saint Antoine, Paris, France
| | - Aurélie Schnuriger
- Institut National de la Santé et de la Recherche Médicale U938, Centre de Recherche de Saint Antoine, Sorbonne Université-Faculté Saint Antoine, Paris, France.,Assistance Publique - Hôpitaux de Paris, Département de Virologie, GHU Paris-Est, Paris, France
| | - Jonathan Pol
- Institut National de la Santé et de la Recherche Médicale U1138, Centre de Recherche des Cordeliers, Université de Paris, Sorbonne Université, Paris, France.,Metabolomics ann Cell Biology Platforms, Gustave Roussy Cancer Campus, Villejuif, France
| | - Patrick Soussan
- Institut National de la Santé et de la Recherche Médicale U938, Centre de Recherche de Saint Antoine, Sorbonne Université-Faculté Saint Antoine, Paris, France .,Assistance Publique - Hôpitaux de Paris, Département de Virologie, GHU Paris-Est, Paris, France
| |
Collapse
|
5
|
Kubina J, Geldreich A, Gales JP, Baumberger N, Bouton C, Ryabova LA, Grasser KD, Keller M, Dimitrova M. Nuclear export of plant pararetrovirus mRNAs involves the TREX complex, two viral proteins and the highly structured 5' leader region. Nucleic Acids Res 2021; 49:8900-8922. [PMID: 34370034 PMCID: PMC8421220 DOI: 10.1093/nar/gkab653] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 07/09/2021] [Accepted: 07/22/2021] [Indexed: 11/13/2022] Open
Abstract
In eukaryotes, the major nuclear export pathway for mature mRNAs uses the dimeric receptor TAP/p15, which is recruited to mRNAs via the multisubunit TREX complex, comprising the THO core and different export adaptors. Viruses that replicate in the nucleus adopt different strategies to hijack cellular export factors and achieve cytoplasmic translation of their mRNAs. No export receptors are known in plants, but Arabidopsis TREX resembles the mammalian complex, with a conserved hexameric THO core associated with ALY and UIEF proteins, as well as UAP56 and MOS11. The latter protein is an orthologue of mammalian CIP29. The nuclear export mechanism for viral mRNAs has not been described in plants. To understand this process, we investigated the export of mRNAs of the pararetrovirus CaMV in Arabidopsis and demonstrated that it is inhibited in plants deficient in ALY, MOS11 and/or TEX1. Deficiency for these factors renders plants partially resistant to CaMV infection. Two CaMV proteins, the coat protein P4 and reverse transcriptase P5, are important for nuclear export. P4 and P5 interact and co-localise in the nucleus with the cellular export factor MOS11. The highly structured 5′ leader region of 35S RNAs was identified as an export enhancing element that interacts with ALY1, ALY3 and MOS11 in vitro.
Collapse
Affiliation(s)
- Julie Kubina
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Angèle Geldreich
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Jón Pol Gales
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Nicolas Baumberger
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Clément Bouton
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Lyubov A Ryabova
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Klaus D Grasser
- Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, D-93053 Regensburg, Germany
| | - Mario Keller
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Maria Dimitrova
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France
| |
Collapse
|
6
|
Liu Y, Veeraraghavan V, Pinkerton M, Fu J, Douglas MW, George J, Tu T. Viral Biomarkers for Hepatitis B Virus-Related Hepatocellular Carcinoma Occurrence and Recurrence. Front Microbiol 2021; 12:665201. [PMID: 34194408 PMCID: PMC8236856 DOI: 10.3389/fmicb.2021.665201] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 05/06/2021] [Indexed: 12/24/2022] Open
Abstract
Hepatocellular carcinoma (HCC) is the sixth most common cancer worldwide and the fourth leading cause of cancer-related death. The most common risk factor for developing HCC is chronic infection with hepatitis B virus (HBV). Early stages of HBV-related HCC (HBV-HCC) are generally asymptomatic. Moreover, while serum alpha-fetoprotein (AFP) and abdominal ultrasound are widely used to screen for HCC, they have poor sensitivity. Thus, HBV-HCC is frequently diagnosed at an advanced stage, in which there are limited treatment options and high mortality rates. Serum biomarkers with high sensitivity and specificity are crucial for earlier diagnosis of HCC and improving survival rates. As viral-host interactions are key determinants of pathogenesis, viral biomarkers may add greater diagnostic power for HCC than host biomarkers alone. In this review, we summarize recent research on using virus-derived biomarkers for predicting HCC occurrence and recurrence; including circulating viral DNA, RNA transcripts, and viral proteins. Combining these viral biomarkers with AFP and abdominal ultrasound could improve sensitivity and specificity of early diagnosis, increasing the survival of patients with HBV-HCC. In the future, as the mechanisms that drive HBV-HCC to become clearer, new biomarkers may be identified which can further improve early diagnosis of HBV-HCC.
Collapse
Affiliation(s)
- Yuanyuan Liu
- Department of Infectious Diseases, The Affiliated Xi'an Central Hospital of Xi'an Jiaotong University, Xi'an, China.,Storr Liver Centre, The Westmead Institute for Medical Research, The University of Sydney and Westmead Hospital, Sydney, NSW, Australia
| | - Vaishnavi Veeraraghavan
- Storr Liver Centre, The Westmead Institute for Medical Research, The University of Sydney and Westmead Hospital, Sydney, NSW, Australia.,School of Medical Science, The University of Sydney, Camperdown, NSW, Australia
| | - Monica Pinkerton
- Storr Liver Centre, The Westmead Institute for Medical Research, The University of Sydney and Westmead Hospital, Sydney, NSW, Australia.,School of Medical Science, The University of Sydney, Camperdown, NSW, Australia
| | - Jianjun Fu
- Department of Infectious Diseases, The Affiliated Xi'an Central Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Mark W Douglas
- Storr Liver Centre, The Westmead Institute for Medical Research, The University of Sydney and Westmead Hospital, Sydney, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia.,Centre for Infectious Diseases and Microbiology, Westmead Hospital, Sydney, NSW, Australia
| | - Jacob George
- Storr Liver Centre, The Westmead Institute for Medical Research, The University of Sydney and Westmead Hospital, Sydney, NSW, Australia
| | - Thomas Tu
- Storr Liver Centre, The Westmead Institute for Medical Research, The University of Sydney and Westmead Hospital, Sydney, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia
| |
Collapse
|
7
|
Lim CS, Sozzi V, Littlejohn M, Yuen LK, Warner N, Betz-Stablein B, Luciani F, Revill PA, Brown CM. Quantitative analysis of the splice variants expressed by the major hepatitis B virus genotypes. Microb Genom 2021; 7:mgen000492. [PMID: 33439114 PMCID: PMC8115900 DOI: 10.1099/mgen.0.000492] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 11/23/2020] [Indexed: 12/13/2022] Open
Abstract
Hepatitis B virus (HBV) is a major human pathogen that causes liver diseases. The main HBV RNAs are unspliced transcripts that encode the key viral proteins. Recent studies have shown that some of the HBV spliced transcript isoforms are predictive of liver cancer, yet the roles of these spliced transcripts remain elusive. Furthermore, there are nine major HBV genotypes common in different regions of the world, these genotypes may express different spliced transcript isoforms. To systematically study the HBV splice variants, we transfected human hepatoma cells, Huh7, with four HBV genotypes (A2, B2, C2 and D3), followed by deep RNA-sequencing. We found that 13-28 % of HBV RNAs were splice variants, which were reproducibly detected across independent biological replicates. These comprised 6 novel and 10 previously identified splice variants. In particular, a novel, singly spliced transcript was detected in genotypes A2 and D3 at high levels. The biological relevance of these splice variants was supported by their identification in HBV-positive liver biopsy and serum samples, and in HBV-infected primary human hepatocytes. Interestingly the levels of HBV splice variants varied across the genotypes, but the spliced pregenomic RNA SP1 and SP9 were the two most abundant splice variants. Counterintuitively, these singly spliced SP1 and SP9 variants had a suboptimal 5' splice site, supporting the idea that splicing of HBV RNAs is tightly controlled by the viral post-transcriptional regulatory RNA element.
Collapse
Affiliation(s)
- Chun Shen Lim
- Department of Biochemistry, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Vitina Sozzi
- Victorian Infectious Diseases Reference Laboratory, Royal Melbourne Hospital at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Margaret Littlejohn
- Victorian Infectious Diseases Reference Laboratory, Royal Melbourne Hospital at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Lilly K.W. Yuen
- Victorian Infectious Diseases Reference Laboratory, Royal Melbourne Hospital at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Nadia Warner
- Victorian Infectious Diseases Reference Laboratory, Royal Melbourne Hospital at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Brigid Betz-Stablein
- Systems Medicine, School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
- Present address: Dermatology Research Centre, Diamantina Institute, University of Queensland, Brisbane, Queensland, Australia
| | - Fabio Luciani
- Systems Medicine, School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Peter A. Revill
- Victorian Infectious Diseases Reference Laboratory, Royal Melbourne Hospital at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
- Department of Microbiology and Immunology, University of Melbourne, Melbourne, Victoria, Australia
| | - Chris M. Brown
- Department of Biochemistry, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| |
Collapse
|
8
|
Shen S, Xie Z, Cai D, Yu X, Zhang H, Kim ES, Zhou B, Hou J, Zhang X, Huang Q, Sun J, Guo H. Biogenesis and molecular characteristics of serum hepatitis B virus RNA. PLoS Pathog 2020; 16:e1008945. [PMID: 33079954 PMCID: PMC7575114 DOI: 10.1371/journal.ppat.1008945] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 08/28/2020] [Indexed: 02/06/2023] Open
Abstract
HBV is an enveloped DNA virus that replicates its DNA genome via reverse transcription of a pregenomic (pg) RNA intermediate in hepatocytes. Interestingly, HBV RNA can be detected in virus-like particles in chronic hepatitis B (CHB) patient serum and has been utilized as a biomarker for intrahepatic cccDNA activity in treated patients. However, the biogenesis and molecular characteristics of serum HBV RNA remain to be fully defined. In this study, we found that the encapsidated serum HBV RNA predominately consists of pgRNA, which are detergent- and ribonuclease-resistant. Through blocking HBV DNA replication without affecting pgRNA encapsidation by using the priming-defective HBV mutant Y63D or 3TC treatment, we demonstrated that the cell culture supernatant contains a large amount of pgRNA-containing nonenveloped capsids and a minor population of pgRNA-containing virions. The formation of pgRNA-virion requires both capsid assembly and viral envelope proteins, which can be inhibited by capsid assembly modulators and an envelope-knockout mutant, respectively. Furthermore, the pgRNA-virion utilizes the multivesicular body pathway for egress, in a similar way as DNA-virion morphogenesis. Northern blotting, RT-PCR, and 3' RACE assays revealed that serum/supernatant HBV pgRNA are mainly spliced and devoid of the 3'-terminal sequences. Furthermore, pgRNA-virion collected from cells treated with a reversible HBV priming inhibitor L-FMAU was unable to establish infection in HepG2-NTCP cells. In summary, serum HBV RNA is secreted in noninfectious virion-like particle as spliced and poly(A)-free pgRNA. Our study will shed light on the molecular biology of serum HBV RNA in HBV life cycle, and aid the development of serum HBV RNA as a novel biomarker for CHB diagnosis and treatment prognosis.
Collapse
Affiliation(s)
- Sheng Shen
- Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, China
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, United States of America
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States of America
| | - Zhanglian Xie
- Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, China
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, United States of America
| | - Dawei Cai
- Assembly Biosciences, Inc., South San Francisco, CA, United States of America
| | - Xiaoyang Yu
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, United States of America
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States of America
| | - Hu Zhang
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, United States of America
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States of America
| | - Elena S. Kim
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, United States of America
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States of America
| | - Bin Zhou
- Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, China
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, United States of America
| | - Jinlin Hou
- Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xiaoyong Zhang
- Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Qi Huang
- Assembly Biosciences, Inc., South San Francisco, CA, United States of America
| | - Jian Sun
- Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Haitao Guo
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, United States of America
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States of America
- Cancer Virology Program, UPMC Hillman Cancer Center, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States of America
| |
Collapse
|
9
|
Yao Z, Jia X, Megger DA, Chen J, Liu Y, Li J, Sitek B, Yuan Z. Label-Free Proteomic Analysis of Exosomes Secreted from THP-1-Derived Macrophages Treated with IFN-α Identifies Antiviral Proteins Enriched in Exosomes. J Proteome Res 2018; 18:855-864. [DOI: 10.1021/acs.jproteome.8b00514] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Zhenlan Yao
- Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Xiaofang Jia
- Shanghai Public Health Clinical Center, Fudan University, Shanghai 201508, China
| | - Dominik A. Megger
- Medizinisches Proteom-Center, Ruhr-Universität Bochum, 44801 Bochum, Germany
- Institute for Virology, University Hospital Essen, University Duisburg-Essen, 50 Virchowstraße 179, 45147 Essen, Germany
| | - Jieliang Chen
- Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Yuyi Liu
- Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Jianhua Li
- Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Barbara Sitek
- Medizinisches Proteom-Center, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Zhenghong Yuan
- Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai 200032, China
| |
Collapse
|
10
|
Abstract
This chapter is the first one to introduce the detection of viral RNA splicing as a new tool for clinical diagnosis of virus infections. These include various infections caused by influenza viruses, human immunodeficiency viruses (HIV), human T-cell leukemia viruses (HTLV), Torque teno viruses (TTV), parvoviruses, adenoviruses, hepatitis B virus, polyomaviruses, herpesviruses, and papillomaviruses. Detection of viral RNA splicing for active viral gene expression in a clinical sample is a nucleic acid-based detection. The interpretation of the detected viral RNA splicing results is straightforward without concern for carry-over DNA contamination, because the spliced RNA is smaller than its corresponding DNA template. Although many methods can be used, a simple method to detect viral RNA splicing is reverse transcription-polymerase chain reaction (RT-PCR). In principle, the detection of spliced RNA transcripts by RT-PCR depends on amplicon selection and primer design. The most common approach is the amplification over the intron regions by a set of primers in flanking exons. A larger product than the predicted size of smaller, spliced RNA is in general an unspliced RNA or contaminating viral genomic DNA. A spliced mRNA always gives a smaller RT-PCR product than its unspliced RNA due to removal of intron sequences by RNA splicing. The contaminating viral DNA can be determined by a minus RT amplification (PCR). Alternatively, specific amplification of a spliced RNA can be obtained by using an exon-exon junction primer because the sequence at exon-exon junction is not present in the unspliced RNA nor in viral genomic DNA.
Collapse
|
11
|
Mitra B, Thapa RJ, Guo H, Block TM. Host functions used by hepatitis B virus to complete its life cycle: Implications for developing host-targeting agents to treat chronic hepatitis B. Antiviral Res 2018; 158:185-198. [PMID: 30145242 PMCID: PMC6193490 DOI: 10.1016/j.antiviral.2018.08.014] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 08/21/2018] [Accepted: 08/22/2018] [Indexed: 02/06/2023]
Abstract
Similar to other mammalian viruses, the life cycle of hepatitis B virus (HBV) is heavily dependent upon and regulated by cellular (host) functions. These cellular functions can be generally placed in to two categories: (a) intrinsic host restriction factors and innate defenses, which must be evaded or repressed by the virus; and (b) gene products that provide functions necessary for the virus to complete its life cycle. Some of these functions may apply to all viruses, but some may be specific to HBV. In certain cases, the virus may depend upon the host function much more than does the host itself. Knowing which host functions regulate the different steps of a virus' life cycle, can lead to new antiviral targets and help in developing novel treatment strategies, in addition to improving a fundamental understanding of viral pathogenesis. Therefore, in this review we will discuss known host factors which influence key steps of HBV life cycle, and further elucidate therapeutic interventions targeting host-HBV interactions.
Collapse
Affiliation(s)
- Bidisha Mitra
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, USA
| | | | - Haitao Guo
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, USA.
| | | |
Collapse
|
12
|
Valaydon ZS, Locarnini SA. The virological aspects of hepatitis B. Best Pract Res Clin Gastroenterol 2017; 31:257-264. [PMID: 28774407 DOI: 10.1016/j.bpg.2017.04.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 04/28/2017] [Indexed: 01/31/2023]
Abstract
Human hepatitis B virus (HBV) is a hepatotropic virus that is responsible for a significant burden of disease, causing liver disease and hepatocellular carcinoma. It is a small DNA virus with a replication strategy that is similar to that of a retrovirus. HBV is prone to mutagenesis and under the influence of diverse selection pressures, has evolved into a pool of quasispecies, genotypes and mutants, which confers a significant survival advantage. The genome is small, circular, and compact but has a complex replication strategy. The viral life cycle involves the formation of a covalently closed circular DNA (cccDNA), which is organized into a minichromosome that is the template for the synthesis of viral mRNA. HBV DNA (double-stranded linear form) can also integrate into the host genome, ensuring lifelong persistence of the virus. To date, despite great advances in therapeutics, once HBV is chronically established, it is incurable. This is by virtue of many aspects of its virological structure and viral life cycle. In this review, we aim to discuss important aspects of the virology of HBV with a focus on clinical implications.
Collapse
Affiliation(s)
- Zina S Valaydon
- Division of Research and Molecular Development, Victorian Infectious Diseases Reference Laboratory, Peter Doherty Institute, Parkville, Victoria, Australia; Department of Gastroenterology, St. Vincent's Hospital, Fitzroy, Victoria, Australia; Department of Medicine, Eastern Hill Academic Centre, The University of Melbourne, Parkville, Victoria, Australia.
| | - Stephen A Locarnini
- Division of Research and Molecular Development, Victorian Infectious Diseases Reference Laboratory, Peter Doherty Institute, Parkville, Victoria, Australia
| |
Collapse
|
13
|
Lim CS, Brown CM. Hepatitis B virus nuclear export elements: RNA stem-loop α and β, key parts of the HBV post-transcriptional regulatory element. RNA Biol 2016; 13:743-7. [PMID: 27031749 DOI: 10.1080/15476286.2016.1166330] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Many viruses contain RNA elements that modulate splicing and/or promote nuclear export of their RNAs. The RNAs of the major human pathogen, hepatitis B virus (HBV) contain a large (~600 bases) composite cis-acting 'post-transcriptional regulatory element' (PRE). This element promotes expression from these naturally intronless transcripts. Indeed, the related woodchuck hepadnavirus PRE (WPRE) is used to enhance expression in gene therapy and other expression vectors. These PRE are likely to act through a combination of mechanisms, including promotion of RNA nuclear export. Functional components of both the HBV PRE and WPRE are 2 conserved RNA cis-acting stem-loop (SL) structures, SLα and SLβ. They are within the coding regions of polymerase (P) gene, and both P and X genes, respectively. Based on previous studies using mutagenesis and/or nuclear magnetic resonance (NMR), here we propose 2 covariance models for SLα and SLβ. The model for the 30-nucleotide SLα contains a G-bulge and a CNGG(U) apical loop of which the first and the fourth loop residues form a CG pair and the fifth loop residue is bulged out, as observed in the NMR structure. The model for the 23-nucleotide SLβ contains a 7-base-pair stem and a 9-nucleotide loop. Comparison of the models with other RNA structural elements, as well as similarity searches of human transcriptome and viral genomes demonstrate that SLα and SLβ are specific to HBV transcripts. However, they are well conserved among the hepadnaviruses of non-human primates, the woodchuck and ground squirrel.
Collapse
Affiliation(s)
- Chun Shen Lim
- a Biochemistry and Genetics Otago , University of Otago , Dunedin , New Zealand
| | - Chris M Brown
- a Biochemistry and Genetics Otago , University of Otago , Dunedin , New Zealand
| |
Collapse
|
14
|
Hepatitis B virus spliced variants are associated with an impaired response to interferon therapy. Sci Rep 2015; 5:16459. [PMID: 26585041 PMCID: PMC4653653 DOI: 10.1038/srep16459] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 10/14/2015] [Indexed: 02/08/2023] Open
Abstract
During hepatitis B virus (HBV) replication, spliced HBV genomes and splice-generated proteins have been widely described, however, their biological and clinical significance remains to be defined. Here, an elevation of the proportion of HBV spliced variants in the sera of patients with chronic hepatitis B (CHB) is shown to correlate with an impaired respond to interferon-α (IFN-α) therapy. Transfection of the constructs encoding the three most dominant species of spliced variants into cells or ectopic expression of the two major spliced protein including HBSP and N-terminal-truncated viral polymerase protein result in strong suppression of IFN-α signaling transduction, while mutation of the major splicing-related sites of HBV attenuates the viral anti-IFN activities in both cell and mouse models. These results have associated the productions of HBV spliced variants with the failure response to IFN therapy and illuminate a novel mechanism where spliced viral products are employed to resist IFN-mediated host defense.
Collapse
|
15
|
Zhang X, Zhu S, Zhu W, Li A, Zhu N. A Newly Identified Natural Splice Variant ASN Enhances Hepatitis B Virus Amplification. Viral Immunol 2015; 29:27-32. [PMID: 26501888 DOI: 10.1089/vim.2015.0044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Chronic hepatitis B virus (HBV) infection causes approximately one-third of all the cases of liver cirrhosis and more than three-quarters of hepatocellular carcinoma (HCC) worldwide. There are eight different genotypes (A-H) of HBV, among which B and C are the major types of HBV in China. There is a positive correlation between viral load and level of viral splicing variants and the high risk of HCC. The aim of this study was to investigate the splicing variants of HBV circulating in HCC patients. Twenty-four carcinoma and adjacent liver tissues collected from HCC patients were studied. Using reverse transcription-polymerase chain reaction (RT-PCR) and sequencing, we identified a new type of natural splice variant with nucleotides 2448-489 and 910-2120 deleted, and we named it ASN. We also found that a higher viral load and splicing variant level existed in liver carcinoma tissues compared to paracarcinoma tissues. In the investigation of our splicing variant, we found its enhancing effect on HBV replication in vitro. Although splicing variants are not essential for the replication of HBV, they may have an important influence.
Collapse
Affiliation(s)
- Xiumin Zhang
- 1 Lab of Molecular Immunology, State Key Lab of Genetic Engineering, Institute of Biomedical Sciences (IBS), School of Life Sciences, Fudan University , Shanghai, People's Republic of China
| | - Sibo Zhu
- 1 Lab of Molecular Immunology, State Key Lab of Genetic Engineering, Institute of Biomedical Sciences (IBS), School of Life Sciences, Fudan University , Shanghai, People's Republic of China
| | - Wei Zhu
- 1 Lab of Molecular Immunology, State Key Lab of Genetic Engineering, Institute of Biomedical Sciences (IBS), School of Life Sciences, Fudan University , Shanghai, People's Republic of China
| | - Aijun Li
- 2 Oriental Liver Surgery Hospital, Second Military Medical University , Shanghai, People's Republic of China
| | - Naishuo Zhu
- 1 Lab of Molecular Immunology, State Key Lab of Genetic Engineering, Institute of Biomedical Sciences (IBS), School of Life Sciences, Fudan University , Shanghai, People's Republic of China
| |
Collapse
|
16
|
Bouton C, Geldreich A, Ramel L, Ryabova LA, Dimitrova M, Keller M. Cauliflower mosaic virus Transcriptome Reveals a Complex Alternative Splicing Pattern. PLoS One 2015; 10:e0132665. [PMID: 26162084 PMCID: PMC4498817 DOI: 10.1371/journal.pone.0132665] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 06/18/2015] [Indexed: 12/23/2022] Open
Abstract
The plant pararetrovirus Cauliflower mosaic virus (CaMV) uses alternative splicing to generate several isoforms from its polycistronic pregenomic 35S RNA. This pro-cess has been shown to be essential for infectivity. Previous works have identified four splice donor sites and a single splice acceptor site in the 35S RNA 5' region and suggested that the main role of CaMV splicing is to downregulate expression of open reading frames (ORFs) I and II. In this study, we show that alternative splicing is a conserved process among CaMV isolates. In Cabb B-JI and Cabb-S isolates, splicing frequently leads to different fusion between ORFs, particularly between ORF I and II. The corresponding P1P2 fusion proteins expressed in E. coli interact with viral proteins P2 and P3 in vitro. However, they are detected neither during infection nor upon transient expression in planta, which suggests rapid degradation after synthesis and no important biological role in the CaMV infectious cycle. To gain a better understanding of the functional relevance of 35S RNA alternative splicing in CaMV infectivity, we inactivated the previously described splice sites. All the splicing mutants were as pathogenic as the corresponding wild-type isolate. Through RT-PCR-based analysis we demonstrate that CaMV 35S RNA exhibits a complex splicing pattern, as we identify new splice donor and acceptor sites whose selection leads to more than thirteen 35S RNA isoforms in infected turnip plants. Inactivating splice donor or acceptor sites is not lethal for the virus, since disrupted sites are systematically rescued by the activation of cryptic and/or seldom used splice sites. Taken together, our data depict a conserved, complex and flexible process, involving multiple sites, that ensures splicing of 35S RNA.
Collapse
Affiliation(s)
- Clément Bouton
- Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, Strasbourg, France
| | - Angèle Geldreich
- Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, Strasbourg, France
| | - Laëtitia Ramel
- Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, Strasbourg, France
| | - Lyubov A. Ryabova
- Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, Strasbourg, France
| | - Maria Dimitrova
- Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, Strasbourg, France
- * E-mail: (MD); (MK)
| | - Mario Keller
- Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, Strasbourg, France
- * E-mail: (MD); (MK)
| |
Collapse
|
17
|
Hao R, Xiang K, Peng Y, Hou J, Sun J, Li Y, Su M, Yan L, Zhuang H, Li T. Naturally occurring deletion/insertion mutations within HBV whole genome sequences in HBeAg-positive chronic hepatitis B patients are correlated with baseline serum HBsAg and HBeAg levels and might predict a shorter interval to HBeAg loss and seroconversion during antiviral treatment. INFECTION GENETICS AND EVOLUTION 2015; 33:261-8. [DOI: 10.1016/j.meegid.2015.05.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 05/10/2015] [Accepted: 05/11/2015] [Indexed: 12/26/2022]
|
18
|
Wei YF, Cui GY, Ye P, Chen JN, Diao HY. MicroRNAs may solve the mystery of chronic hepatitis B virus infection. World J Gastroenterol 2013; 19:4867-4876. [PMID: 23946591 PMCID: PMC3740416 DOI: 10.3748/wjg.v19.i30.4867] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2013] [Revised: 06/04/2013] [Accepted: 07/05/2013] [Indexed: 02/06/2023] Open
Abstract
Hepatitis B virus (HBV) infection is a global public health problem that causes persistent liver diseases such as chronic hepatitis, cirrhosis, and hepatocellular carcinoma. A large amount of people die annually from HBV infection. However, the pathogenesises of the HBV-related diseases are ill defined and the therapeutic strategies for the diseases are less than optimum. The recently discovered microRNAs (miRNAs) are tiny noncoding RNAs that regulate gene expression primarily at the post-transcriptional level by binding to mRNAs. miRNAs contribute to a variety of physiological and pathological processes. A number of miRNAs have been found to play a pivotal role in the host-virus interaction including host-HBV interaction. Numerous studies have indicated that HBV infection could change the cellular miRNA expression patterns and different stages of HBV associated disease have displayed distinctive miRNA profiles. Furthermore, the differential expressed miRNAs have been found involved in the progression of HBV-related diseases, for instance some miRNAs are involved in liver tumorigenesis and tumor metastasis. Studies have also shown that the circulating miRNA in serum or plasma might be a very useful biomarker for the diagnosis and prognosis of HBV-related diseases. In addition, miRNA-based therapy strategies have attracted increasing attention, indicating a promising future in the treatment of HBV-related diseases.
Collapse
|
19
|
Chen J, Wu M, Zhang X, Zhang W, Zhang Z, Chen L, He J, Zheng Y, Chen C, Wang F, Hu Y, Zhou X, Wang C, Xu Y, Lu M, Yuan Z. Hepatitis B virus polymerase impairs interferon-α-induced STA T activation through inhibition of importin-α5 and protein kinase C-δ. Hepatology 2013; 57:470-82. [PMID: 22996189 DOI: 10.1002/hep.26064] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 08/30/2012] [Indexed: 12/24/2022]
Abstract
UNLABELLED Treatment with exogenous interferon (IFN)-α is not effective in the majority of patients with chronic hepatitis B virus (HBV) infection. Recent evidence suggests that HBV has evolved strategies to block the nuclear translocation of signal transducer and activator of transcription (STAT) 1 to limit IFN-α-induced cellular antiviral responses. However, it remains unclear whether STAT1 translocation is impaired in chronic hepatitis B patients and what mechanisms are involved. Here we report that the expression of HBV polymerase (Pol) in human hepatic cell lines inhibited induction of IFN-stimulated genes and resulted in a weakened antiviral activity of IFN-α. Ectopic expression of Pol suppressed IFN-α-induced STAT1 serine 727 phosphorylation and STAT1/2 nuclear accumulation, whereas STAT1 tyrosine 701 phosphorylation, and STAT1-STAT2 heterodimer formation were not affected. Further studies demonstrated that Pol interacted with the catalytic domain of protein kinase C-δ (PKC-δ) and perturbed PKC-δ phosphorylation and its association with STAT1, which resulted in the suppression of STAT1 Ser727 phosphorylation. Moreover, Pol was found to interfere with nuclear transportation of STAT1/2 by competitively binding to the region of importin-α5 required for STAT1/2 recruitment. Truncation analysis suggested that the terminal protein and RNase H domains of Pol were able to bind to PKC-δ and importin-α5, respectively, and were responsible for the inhibition of IFN-α signaling. More importantly, the inhibition of STAT1 and PKC-δ phosphorylation were confirmed in a hydrodynamic-based HBV mouse model, and the blockage of IFN-α-induced STAT1/2 nuclear translocation was observed in HBV-infected cells from liver biopsies of chronic HBV patients. CONCLUSIONS These results demonstrate a role for Pol in HBV-mediated antagonization of IFN-α signaling and provide a possible molecular mechanism by which HBV resists the IFN therapy and maintains its persistence.
Collapse
Affiliation(s)
- Jieliang Chen
- Key Laboratory of Medical Molecular Virology, Ministry of Education and HealthShanghai Medical College of Fudan University, Shanghai, China
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Tang YW, Stratton CW. Detection of Viral RNA Splicing in Diagnostic Virology. ADVANCED TECHNIQUES IN DIAGNOSTIC MICROBIOLOGY 2013. [PMCID: PMC7120143 DOI: 10.1007/978-1-4614-3970-7_38] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Yi-Wei Tang
- Department of Laboratory Medicine, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, 10065 New York USA
| | - Charles W. Stratton
- Vanderbilt Clinic, Clinical Microbiology Laboratory, Vanderbilt University Medical Center, 22nd Avenue 1301, Nashville, 37232-5310 Tennessee USA
| |
Collapse
|
21
|
Abstract
Persistent infection with cancer risk-related viruses leads to molecular, cellular and immune response changes in host organisms that in some cases direct cellular transformation. Alternative splicing is a conserved cellular process that increases the coding complexity of genomes at the pre-mRNA processing stage. Human and other animal tumour viruses use alternative splicing as a process to maximize their transcriptomes and proteomes. Medical therapeutics to clear persistent viral infections are still limited. However, specific lessons learned in some viruses [e.g. HIV and HCV (hepatitis C virus)] suggest that drug-directed inhibition of alternative splicing could be useful for this purpose. The present review describes the basic mechanisms of constitutive and alternative splicing in a cellular context and known splicing patterns and the mechanisms by which these might be achieved for the major human infective tumour viruses. The roles of splicing-related proteins expressed by these viruses in cellular and viral gene regulation are explored. Moreover, we discuss some currently available drugs targeting SR (serine/arginine-rich) proteins that are the main regulators of constitutive and alternative splicing, and their potential use in treatment for so-called persistent viral infections.
Collapse
|
22
|
Köck J, Rösler C, Zhang J, Blum HE, Nassal M, Thoma C. Human hepatitis B virus production in avian cells is characterized by enhanced RNA splicing and the presence of capsids containing shortened genomes. PLoS One 2012; 7:e37248. [PMID: 22624002 PMCID: PMC3356268 DOI: 10.1371/journal.pone.0037248] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 04/16/2012] [Indexed: 01/25/2023] Open
Abstract
Experimental studies on hepatitis B virus (HBV) replication are commonly done with human hepatoma cells to reflect the natural species and tissue tropism of the virus. However, HBV can also replicate, upon transfection of virus coding plasmids, in cells of other species. In such cross-species transfection experiments with chicken LMH hepatoma cells, we previously observed the formation of HBV genomes with aberrant electrophoretic mobility, in addition to the those DNA species commonly seen in human HepG2 hepatoma cells. Here, we report that these aberrant DNA forms are mainly due to excessive splicing of HBV pregenomic RNA and the abundant synthesis of spliced DNA products, equivalent to those also made in human cells, yet at much lower level. Mutation of the common splice acceptor site abolished splicing and in turn enhanced production of DNA from full-length pgRNA in transfected LMH cells. The absence of splicing made other DNA molecules visible, that were shortened due to the lack of sequences in the core protein coding region. Furthermore, there was nearly full-length DNA in the cytoplasm of LMH cells that was not protected in viral capsids. Remarkably, we have previously observed similar shortened genomes and non-protected viral DNA in human HepG2 cells, yet exclusively in the nucleus where uncoating and final release of viral genomes occurs. Hence, two effects reflecting capsid disassembly in the nucleus in human HepG2 cells are seen in the cytoplasm of chicken LMH cells.
Collapse
Affiliation(s)
- Josef Köck
- Department of Medicine II, University Hospital of Freiburg, Freiburg, Germany
- * E-mail: (JK); (CT)
| | - Christine Rösler
- Department of Medicine II, University Hospital of Freiburg, Freiburg, Germany
| | - Jingjing Zhang
- Department of Medicine II, University Hospital of Freiburg, Freiburg, Germany
| | - Hubert E. Blum
- Department of Medicine II, University Hospital of Freiburg, Freiburg, Germany
| | - Michael Nassal
- Department of Medicine II, University Hospital of Freiburg, Freiburg, Germany
| | - Christian Thoma
- Department of Medicine II, University Hospital of Freiburg, Freiburg, Germany
- * E-mail: (JK); (CT)
| |
Collapse
|
23
|
Liu WH, Yeh SH, Chen PJ. Role of microRNAs in hepatitis B virus replication and pathogenesis. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2011; 1809:678-85. [DOI: 10.1016/j.bbagrm.2011.04.008] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2011] [Revised: 04/24/2011] [Accepted: 04/25/2011] [Indexed: 02/08/2023]
|
24
|
Köck J, Rösler C, Zhang JJ, Blum HE, Nassal M, Thoma C. Generation of covalently closed circular DNA of hepatitis B viruses via intracellular recycling is regulated in a virus specific manner. PLoS Pathog 2010; 6:e1001082. [PMID: 20824087 PMCID: PMC2932716 DOI: 10.1371/journal.ppat.1001082] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Accepted: 07/29/2010] [Indexed: 12/12/2022] Open
Abstract
Persistence of hepatitis B virus (HBV) infection requires covalently closed circular (ccc)DNA formation and amplification, which can occur via intracellular recycling of the viral polymerase-linked relaxed circular (rc) DNA genomes present in virions. Here we reveal a fundamental difference between HBV and the related duck hepatitis B virus (DHBV) in the recycling mechanism. Direct comparison of HBV and DHBV cccDNA amplification in cross-species transfection experiments showed that, in the same human cell background, DHBV but not HBV rcDNA converts efficiently into cccDNA. By characterizing the distinct forms of HBV and DHBV rcDNA accumulating in the cells we find that nuclear import, complete versus partial release from the capsid and complete versus partial removal of the covalently bound polymerase contribute to limiting HBV cccDNA formation; particularly, we identify genome region-selectively opened nuclear capsids as a putative novel HBV uncoating intermediate. However, the presence in the nucleus of around 40% of completely uncoated rcDNA that lacks most if not all of the covalently bound protein strongly suggests a major block further downstream that operates in the HBV but not DHBV recycling pathway. In summary, our results uncover an unexpected contribution of the virus to cccDNA formation that might help to better understand the persistence of HBV infection. Moreover, efficient DHBV cccDNA formation in human hepatoma cells should greatly facilitate experimental identification, and possibly inhibition, of the human cell factors involved in the process. Persistent infection with hepatitis B virus (HBV) causes chronic hepatitis B which frequently progresses to hepatocellular carcinoma, a leading cause of cancer-mediated mortality worldwide. Persistence requires formation and amplification of covalently closed circular (ccc)DNA, an episomal form of the viral genome that is not targeted by current drugs and thus is responsible for the notorious difficulties in therapeutic elimination of infection. Initial generation of cccDNA occurs upon nuclear import of the virion-borne relaxed circular (rc) DNA to which the viral polymerase is covalently linked; amplification occurs via intracellular recycling. The underlying molecular pathway is poorly understood. Because HBV infects only primates, in vivo studies are extremely restricted; in vitro, select hepatoma cell lines transfected with HBV support viral replication, however with little if any cccDNA formation. Here, we compared intracellular recycling of HBV and DHBV, a model hepatitis B virus from ducks, in cross-species transfections. Surprisingly, the major contribution to cccDNA formation comes from the virus rather than the cell as DHBV but not HBV rcDNA converted efficiently into cccDNA in the same human cell background. This unexpected difference might help to better understand persistence of HBV infection; efficient DHBV cccDNA formation in human cells provides a new tool to facilitate identification, and possibly targeting, of the human cell factors involved.
Collapse
MESH Headings
- Active Transport, Cell Nucleus
- Animals
- Cell Nucleus/genetics
- Cell Nucleus/metabolism
- DNA, Circular/genetics
- DNA, Viral/genetics
- Genome, Viral
- Hepadnaviridae Infections/genetics
- Hepadnaviridae Infections/metabolism
- Hepadnaviridae Infections/virology
- Hepatitis B/genetics
- Hepatitis B/metabolism
- Hepatitis B/virology
- Hepatitis B Virus, Duck/genetics
- Hepatitis B virus/genetics
- Hepatitis, Viral, Animal/genetics
- Hepatitis, Viral, Animal/metabolism
- Hepatitis, Viral, Animal/virology
- Humans
- Immunoprecipitation
- Polymerase Chain Reaction
- Recycling
- Virion/genetics
- Virus Replication/genetics
Collapse
Affiliation(s)
- Josef Köck
- Department of Medicine II, University Hospital of Freiburg, Freiburg, Germany
| | - Christine Rösler
- Department of Medicine II, University Hospital of Freiburg, Freiburg, Germany
| | - Jing-Jing Zhang
- Department of Medicine II, University Hospital of Freiburg, Freiburg, Germany
| | - Hubert E. Blum
- Department of Medicine II, University Hospital of Freiburg, Freiburg, Germany
| | - Michael Nassal
- Department of Medicine II, University Hospital of Freiburg, Freiburg, Germany
- * E-mail: (CT); (MN)
| | - Christian Thoma
- Department of Medicine II, University Hospital of Freiburg, Freiburg, Germany
- * E-mail: (CT); (MN)
| |
Collapse
|
25
|
HBV life cycle: entry and morphogenesis. Viruses 2009; 1:185-209. [PMID: 21994545 PMCID: PMC3185491 DOI: 10.3390/v1020185] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2009] [Revised: 07/31/2009] [Accepted: 08/13/2009] [Indexed: 02/07/2023] Open
Abstract
Hepatitis B virus (HBV) is a major cause of liver disease. HBV primarily infects hepatocytes by a still poorly understood mechanism. After an endocytotic process, the nucleocapsids are released into the cytoplasm and the relaxed circular rcDNA genome is transported towards the nucleus where it is converted into covalently closed circular cccDNA. Replication of the viral genome occurs via an RNA pregenome (pgRNA) that binds to HBV polymerase (P). P initiates pgRNA encapsidation and reverse transcription inside the capsid. Matured, rcDNA containing nucleocapsids can re-deliver the RC-DNA to the nucleus, or be secreted via interaction with the envelope proteins as progeny virions.
Collapse
|
26
|
Analysis of hepatitis B virus X gene phylogeny, genetic variability and its impact on pathogenesis: implications in Eastern Indian HBV carriers. Virology 2008; 382:190-8. [PMID: 18952249 DOI: 10.1016/j.virol.2008.09.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Revised: 08/15/2008] [Accepted: 09/04/2008] [Indexed: 02/07/2023]
Abstract
HBx genetic variability was explored in the Eastern Indian population with low HCC incidence. DNase I sensitive HBV DNA was detected in 53% samples, which differed significantly between clinical groups (P<0.001). HBV genotypes A (Aa/A1), C (Cs/C1) and D (D1, D2, D3, D5) were detected in 37.5%, 18.7% and 43.7% samples respectively. Population specific signature HBx residues A(36), V(88), S(101) in Aa/A1 and residues P(41), Q(110) in D5 were detected. Mutations T(127), M(130) and I(131) were detected in 66.7%, 91% and 75% of genotype A, C and D5 samples respectively. Very low occurrence of HCC associated mutations (V(5)M/L, P(38)S, and H(94)Y) and absence of C-terminal deletions were observed. Our study shows that HBV genotype associated clinically important HBx variations may evolve and act distinctly in different geo-ethnic populations. Further studies on HBx functions from the perspective of genetic variability are essential for the better understanding of the clinical significance of HBV.
Collapse
|