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The Nucleocapsid of Paramyxoviruses: Structure and Function of an Encapsidated Template. Viruses 2021; 13:v13122465. [PMID: 34960734 PMCID: PMC8708338 DOI: 10.3390/v13122465] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 12/07/2021] [Accepted: 12/07/2021] [Indexed: 01/28/2023] Open
Abstract
Viruses of the Paramyxoviridae family share a common and complex molecular machinery for transcribing and replicating their genomes. Their non-segmented, negative-strand RNA genome is encased in a tight homopolymer of viral nucleoproteins (N). This ribonucleoprotein complex, termed a nucleocapsid, is the template of the viral polymerase complex made of the large protein (L) and its co-factor, the phosphoprotein (P). This review summarizes the current knowledge on several aspects of paramyxovirus transcription and replication, including structural and functional data on (1) the architecture of the nucleocapsid (structure of the nucleoprotein, interprotomer contacts, interaction with RNA, and organization of the disordered C-terminal tail of N), (2) the encapsidation of the genomic RNAs (structure of the nucleoprotein in complex with its chaperon P and kinetics of RNA encapsidation in vitro), and (3) the use of the nucleocapsid as a template for the polymerase complex (release of the encased RNA and interaction network allowing the progress of the polymerase complex). Finally, this review presents models of paramyxovirus transcription and replication.
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2
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Meng Q, He J, Zhong L, Zhao Y. Advances in the Study of Antitumour Immunotherapy for Newcastle Disease Virus. Int J Med Sci 2021; 18:2294-2302. [PMID: 33967605 PMCID: PMC8100649 DOI: 10.7150/ijms.59185] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 03/21/2021] [Indexed: 01/08/2023] Open
Abstract
This article reviews the preclinical research, clinical application and development of Newcastle disease virus (NDV) in the field of cancer therapy. Based on the distinctive antitumour properties of NDV and its positive interaction with the patient's immune system, this biologic could be considered a major breakthrough in cancer treatment. On one hand, NDV infection creates an inflammatory environment in the tumour microenvironment, which can directly activate NK cells, monocytes, macrophages and dendritic cells and promote the recruitment of immune cells. On the other hand, NDV can induce the upregulation of immune checkpoint molecules, which may break immune tolerance and immune checkpoint blockade resistance. In fact, clinical data have shown that NDV combined with immune checkpoint blockade can effectively enhance the antitumour response, leading to the regression of local tumours and distant tumours when injected, and this effect is further enhanced by targeted manipulation and modification of the NDV genome. At present, recombinant NDV and recombinant NDV combined with immune checkpoint blockers have entered different stages of clinical trials. Based on these studies, further research on NDV is warranted.
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Affiliation(s)
- Qiuxing Meng
- National Center for International Research of Bio-targeting Theranostics, Guangxi Key Laboratory of Bio-targeting Theranostics, Collaborative Innovation Center for Targeting Tumor Diagnosis and Therapy, Guangxi Talent Highland of Bio-targeting Theranostics, Guangxi Medical University, Nanning, Guangxi, China
| | - Jian He
- National Center for International Research of Bio-targeting Theranostics, Guangxi Key Laboratory of Bio-targeting Theranostics, Collaborative Innovation Center for Targeting Tumor Diagnosis and Therapy, Guangxi Talent Highland of Bio-targeting Theranostics, Guangxi Medical University, Nanning, Guangxi, China
| | - Liping Zhong
- National Center for International Research of Bio-targeting Theranostics, Guangxi Key Laboratory of Bio-targeting Theranostics, Collaborative Innovation Center for Targeting Tumor Diagnosis and Therapy, Guangxi Talent Highland of Bio-targeting Theranostics, Guangxi Medical University, Nanning, Guangxi, China
| | - Yongxiang Zhao
- National Center for International Research of Bio-targeting Theranostics, Guangxi Key Laboratory of Bio-targeting Theranostics, Collaborative Innovation Center for Targeting Tumor Diagnosis and Therapy, Guangxi Talent Highland of Bio-targeting Theranostics, Guangxi Medical University, Nanning, Guangxi, China
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Jadhav A, Zhao L, Liu W, Ding C, Nair V, Ramos-Onsins SE, Ferretti L. Genomic Diversity and Evolution of Quasispecies in Newcastle Disease Virus Infections. Viruses 2020; 12:v12111305. [PMID: 33202558 PMCID: PMC7698180 DOI: 10.3390/v12111305] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 10/31/2020] [Accepted: 11/06/2020] [Indexed: 12/19/2022] Open
Abstract
Newcastle disease virus (NDV) infections are well known to harbour quasispecies, due to the error-prone nature of the RNA polymerase. Quasispecies variants in the fusion cleavage site of the virus are known to significantly change its virulence. However, little is known about the genomic patterns of diversity and selection in NDV viral swarms. We analyse deep sequencing data from in vitro and in vivo NDV infections to uncover the genomic patterns of diversity and the signatures of selection within NDV swarms. Variants in viruses from in vitro samples are mostly localised in non-coding regions and 3′ and 5′ untranslated regions (3′UTRs or 5′UTRs), while in vivo samples contain an order of magnitude more variants. We find different patterns of genomic divergence and diversity among NDV genotypes, as well as differences in the genomic distribution of intra-host variants among in vitro and in vivo infections of the same strain. The frequency spectrum shows clear signatures of intra-host purifying selection in vivo on the matrix protein (M) coding gene and positive or diversifying selection on nucleocapsid (NP) and haemagglutinin-neuraminidase (HN). The comparison between within-host polymorphisms and phylogenetic divergence reveals complex patterns of selective pressure on the NDV genome at between- and within-host level. The M sequence is strongly constrained both between and within hosts, fusion protein (F) coding gene is under intra-host positive selection, and NP and HN show contrasting patterns: HN RNA sequence is positively selected between hosts while its protein sequence is positively selected within hosts, and NP is under intra-host positive selection at the RNA level and negative selection at the protein level.
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Affiliation(s)
- Archana Jadhav
- Viral Oncogenesis Group, The Pirbright Institute, Pirbright, Woking GU24 0NF, Surrey, UK; (A.J.); (V.N.)
| | - Lele Zhao
- Nuffield Department of Medicine, Li Ka Shing Centre for Health Information and Discovery, Big Data Institute, University of Oxford, Oxford OX3 7LF, UK;
| | - Weiwei Liu
- Department of Avian Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China; (W.L.); (C.D.)
| | - Chan Ding
- Department of Avian Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China; (W.L.); (C.D.)
| | - Venugopal Nair
- Viral Oncogenesis Group, The Pirbright Institute, Pirbright, Woking GU24 0NF, Surrey, UK; (A.J.); (V.N.)
- UK-China Centre of Excellence on Avian Disease Research, Pirbright, Woking GU24 0NF, Surrey, UK
| | - Sebastian E. Ramos-Onsins
- Plant and Animal Genomics, Centre de Recerca en Agrigenòmica (CRAG) CSIC-IRTA-UAB-UB, 08193 Bellaterra, Spain
- Correspondence: (S.E.R.-O.); (L.F.)
| | - Luca Ferretti
- Nuffield Department of Medicine, Li Ka Shing Centre for Health Information and Discovery, Big Data Institute, University of Oxford, Oxford OX3 7LF, UK;
- Correspondence: (S.E.R.-O.); (L.F.)
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4
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Pong LY, Rabu A, Ibrahim N. The critical region for viral RNA encapsidation in leader promoter of Nipah virus. Mol Genet Genomics 2020; 295:1501-1516. [PMID: 32767127 DOI: 10.1007/s00438-020-01716-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 07/25/2020] [Indexed: 01/19/2023]
Abstract
Encapsidation by nucleocapsid (N) protein is crucial for viral RNA to serve as a functional template for virus replication. However, the potential region that is vital for RNA encapsidation of Nipah virus (NiV) is still unknown. Thus, this study was aimed to identify these regions using a NiV minireplicon system. A series of broad range internal deletion mutations was generated in the 5' non-translated region (NTR) of the N gene mRNA region of NiV leader promoter via site-directed overlapping PCR-mediated mutagenesis. The mutation effects on synthesis and encapsidation of antigenome RNA, transcription, and RNA binding affinity of N protein were evaluated. The deletions of nucleotides 73-108, 79-108, and 85-108 from NiV leader promoter inhibited the encapsidation of antigenome RNA, while the deletion of nucleotides 103-108 suppressed the synthesis and encapsidation of antigenome RNA, implying that these regions are required for genome replication. Surprisingly, none of the mutations had detrimental effect on viral transcription. Using isothermal titration calorimetry, the binding of NiV N protein to genome or antigenome RNA transcript lacking of nucleotides 73-108 was found to be suppressed. Additionally, in silico analysis on secondary structure of genome RNA further supported the plausible cause of inefficient encapsidation of antigenome RNA by the loss of encapsidation signal in genome template. In conclusion, this study suggests that the nucleotides 73-90 within 5' NTR of the N gene mRNA region in NiV leader promoter contain cis-acting RNA element that is important for efficient encapsidation of antigenome RNA.
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Affiliation(s)
- Lian Yih Pong
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600, UKM Bangi, Selangor Darul Ehsan, Malaysia.,Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Jalan Lagoon Selatan, 47500, Bandar Sunway, Selangor Darul Ehsan, Malaysia
| | - Amir Rabu
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600, UKM Bangi, Selangor Darul Ehsan, Malaysia
| | - Nazlina Ibrahim
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600, UKM Bangi, Selangor Darul Ehsan, Malaysia.
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Ogonczyk Makowska D, Hamelin MÈ, Boivin G. Engineering of Live Chimeric Vaccines against Human Metapneumovirus. Pathogens 2020; 9:E135. [PMID: 32093057 PMCID: PMC7168645 DOI: 10.3390/pathogens9020135] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 02/12/2020] [Accepted: 02/14/2020] [Indexed: 02/07/2023] Open
Abstract
Human metapneumovirus (HMPV) is an important human pathogen that, along with respiratory syncytial virus (RSV), is a major cause of respiratory tract infections in young infants. Development of an effective vaccine against Pneumoviruses has proven to be particularly difficult; despite over 50 years of research in this field, no vaccine against HMPV or RSV is currently available. Recombinant chimeric viruses expressing antigens of other viruses can be generated by reverse genetics and used for simultaneous immunization against more than one pathogen. This approach can result in the development of promising vaccine candidates against HMPV, and several studies have indeed validated viral vectors expressing HMPV antigens. In this review, we summarize current efforts in generating recombinant chimeric vaccines against HMPV, and we discuss their potential optimization based on the correspondence with RSV studies.
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Affiliation(s)
| | | | - Guy Boivin
- Centre de Recherche en Infectiologie of the Centre Hospitalier Universitaire de Québec and Université Laval, Québec, QC G1V 4G2, Canada; (D.O.M.); (M.-È.H.)
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Vijayakumar G, Zamarin D. Design and Production of Newcastle Disease Virus for Intratumoral Immunomodulation. Methods Mol Biol 2020; 2058:133-154. [PMID: 31486036 DOI: 10.1007/978-1-4939-9794-7_9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Newcastle disease virus (NDV) is an avian paramyxovirus that has been extensively studied as an oncolytic agent, in addition to being an economically important pathogen in the poultry industry. The establishment of a reverse genetics system for this virus has enabled the development of genetically modified recombinant NDV viruses with improved oncolytic and immunotherapeutic properties. In this chapter, we describe the materials and methods involved in the in vitro cloning and rescue of NDV expressing murine 4-1BBL as well as the in vivo evaluation of NDV expressing 4-1BBL in a B16-F10 murine melanoma model.
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Affiliation(s)
- Gayathri Vijayakumar
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Dmitriy Zamarin
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA. .,Department of Medicine, Weil Cornell Medical College, New York, NY, USA. .,Parker Institute for Cancer Immunotherapy, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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7
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Fearns R, Plemper RK. Polymerases of paramyxoviruses and pneumoviruses. Virus Res 2017; 234:87-102. [PMID: 28104450 DOI: 10.1016/j.virusres.2017.01.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Revised: 01/06/2017] [Accepted: 01/09/2017] [Indexed: 11/13/2022]
Abstract
The paramyxo- and pneumoviruses are members of the order Mononegavirales, a group of viruses with non-segmented, negative strand RNA genomes. The polymerases of these viruses are multi-functional complexes, capable of transcribing subgenomic capped and polyadenylated mRNAs and replicating the genome. Although there is no native structure available for any complete paramyxo- or pneumovirus polymerase, functional and structural studies of a fragment of a pneumovirus polymerase protein and mutation analyses and resistance profiling of small-molecule inhibitors have generated a wealth of mechanistic information. This review integrates these data with the structure of a related polymerase, identifying similarities, differences, gaps in knowledge, and avenues for antiviral drug development.
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Affiliation(s)
- Rachel Fearns
- Department of Microbiology, Boston University School of Medicine, Boston, MA 02118, United States.
| | - Richard K Plemper
- Institute for Biomedical Sciences, Georgia State University, Atlanta, GA 30303, United States
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Yamamoto E, Ito T, Ito H. Completion of full length genome sequence of novel avian paramyxovirus strain APMV/Shimane67 isolated from migratory wild geese in Japan. J Vet Med Sci 2016; 78:1583-1594. [PMID: 27430258 PMCID: PMC5095628 DOI: 10.1292/jvms.16-0264] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The nucleotide sequences of nucleocapsid protein (N); phosphoprotein (P); matrix protein (M); hemagglutinin-neuraminidase (HN); and large polymerase protein (L) genes, 3'-end leader, 5'-end trailer and intergenic regions of the avian paramyxovirus (APMV) strain goose/Shimane/67/2000 (APMV/Shimane67) were determined. Together with previously reported data on fusion protein (F) gene sequence [46], the determination of the genome sequence of APMV/Shimane67 has been completed in this study. The genome of APMV/Shimane67 comprised 16,146 nucleotides in length and contains six genes in the order of 3'-N-P-M-F-HN-L-5'. The features of the APMV/Shimane67 genome (e.g., nucleotide length of whole genome and each of the six genes, and predicted amino acid length of each of the six genes) were distinct from those of other APMV serotypes. Phylogenetic analysis indicated that although APMV/Shimane67 was grouped with APMV-1, -9 and -12, the evolutionary distance between APMV/Shimane67 and these viruses was longer than that observed between intra-serotype viruses. These results show that the genome sequence of APMV/Shimane67 contains specific characteristics and is distinguishable from other types of APMV.
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Affiliation(s)
- Eiji Yamamoto
- United Graduate School of Veterinary Sciences, Yamaguchi University, Yamaguchi 753-8515, Japan
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Zhang Z, Zhao W, Li D, Yang J, Zsak L, Yu Q. Development of a Newcastle disease virus vector expressing a foreign gene through an internal ribosomal entry site provides direct proof for a sequential transcription mechanism. J Gen Virol 2015; 96:2028-2035. [DOI: 10.1099/vir.0.000142] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Zhenyu Zhang
- College of Life Sciences, Northeast Agricultural University, Harbin, Heilongjiang 150030, PR China
- United States Department of Agriculture, U.S. National Poultry Research Center, Agricultural Research Services, 934 College Station Road, Athens, GA, 30605, USA
| | - Wei Zhao
- United States Department of Agriculture, U.S. National Poultry Research Center, Agricultural Research Services, 934 College Station Road, Athens, GA, 30605, USA
- Beijing Centre for Disease Control and Prevention, Beijing 100013, PR China
| | - Deshan Li
- College of Life Sciences, Northeast Agricultural University, Harbin, Heilongjiang 150030, PR China
| | - Jinlong Yang
- United States Department of Agriculture, U.S. National Poultry Research Center, Agricultural Research Services, 934 College Station Road, Athens, GA, 30605, USA
- Chongqing Academy of Animal Sciences, Chongqing 402460, PR China
| | - Laszlo Zsak
- United States Department of Agriculture, U.S. National Poultry Research Center, Agricultural Research Services, 934 College Station Road, Athens, GA, 30605, USA
| | - Qingzhong Yu
- United States Department of Agriculture, U.S. National Poultry Research Center, Agricultural Research Services, 934 College Station Road, Athens, GA, 30605, USA
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10
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Initiation and regulation of paramyxovirus transcription and replication. Virology 2015; 479-480:545-54. [PMID: 25683441 DOI: 10.1016/j.virol.2015.01.014] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 01/04/2015] [Indexed: 12/18/2022]
Abstract
The paramyxovirus family has a genome consisting of a single strand of negative sense RNA. This genome acts as a template for two distinct processes: transcription to generate subgenomic, capped and polyadenylated mRNAs, and genome replication. These viruses only encode one polymerase. Thus, an intriguing question is, how does the viral polymerase initiate and become committed to either transcription or replication? By answering this we can begin to understand how these two processes are regulated. In this review article, we present recent findings from studies on the paramyxovirus, respiratory syncytial virus, which show how its polymerase is able to initiate transcription and replication from a single promoter. We discuss how these findings apply to other paramyxoviruses. Then, we examine how trans-acting proteins and promoter secondary structure might serve to regulate transcription and replication during different phases of the paramyxovirus replication cycle.
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The viral replication complex is associated with the virulence of Newcastle disease virus. J Virol 2010; 84:10113-20. [PMID: 20660202 DOI: 10.1128/jvi.00097-10] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Virulent strains of Newcastle disease virus ([NDV] also known as avian paramyxovirus type 1) can be discriminated from low-virulence strains by the presence of multiple basic amino acid residues at the proteolytic cleavage site of the fusion (F) protein. However, some NDV variants isolated from pigeons (pigeon paramyxovirus type 1 [PPMV-1]) have low levels of virulence, despite the fact that their F protein cleavage sites contain a multibasic amino acid sequence and have the same functionality as that of virulent strains. To determine the molecular basis of this discrepancy, we examined the role of the internal proteins in NDV virulence. Using reverse genetics, the genes encoding the nucleoprotein (NP), phosphoprotein (P), matrix protein (M), and large polymerase protein (L) were exchanged between the nonvirulent PPMV-1 strain AV324 and the highly virulent NDV strain Herts. Recombinant viruses were evaluated for their pathogenicities and replication levels in day-old chickens, and viral genome replication and plaque sizes were examined in cell culture monolayers. We also tested the contributions of the individual NP, P, and L proteins to the activity of the viral replication complex in an in vitro replication assay. The results showed that the replication proteins of Herts are more active than those of AV324 and that the activity of the viral replication complex is directly related to virulence. Although the M protein affected viral replication in vitro, it had only a minor effect on virulence.
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The complete sequence of a human parainfluenzavirus 4 genome. Viruses 2009; 1:26-41. [PMID: 21994536 PMCID: PMC3185463 DOI: 10.3390/v1010026] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Revised: 05/22/2009] [Accepted: 05/26/2009] [Indexed: 02/06/2023] Open
Abstract
Although the human parainfluenza virus 4 (HPIV4) has been known for a long time, its genome, alone among the human paramyxoviruses, has not been completely sequenced to date. In this study we obtained the first complete genomic sequence of HPIV4 from a clinical isolate named SKPIV4 obtained at the Hospital for Sick Children in Toronto (Ontario, Canada). The coding regions for the N, P/V, M, F and HN proteins show very high identities (95% to 97%) with previously available partial sequences for HPIV4B. The sequence for the L protein and the non-coding regions represent new information. A surprising feature of the genome is its length, more than 17 kb, making it the longest genome within the genus Rubulavirus, although the length is well within the known range of 15 kb to 19 kb for the subfamily Paramyxovirinae. The availability of a complete genomic sequence will facilitate investigations on a respiratory virus that is still not completely characterized.
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The marburg virus 3' noncoding region structurally and functionally differs from that of ebola virus. J Virol 2009; 83:4508-19. [PMID: 19225002 DOI: 10.1128/jvi.02429-08] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have previously shown that the first transcription start signal (TSS) of Zaire Ebola virus (ZEBOV) is involved in formation of an RNA secondary structure regulating VP30-dependent transcription activation. Interestingly, transcription of Marburg virus (MARV) minigenomes occurs independently of VP30. In this study, we analyzed the structure of the MARV 3' noncoding region and its influence on VP30 necessity. Secondary structure formation of the TSS of the first gene was experimentally determined and showed substantial differences from the structure formed by the ZEBOV TSS. Chimeric MARV minigenomes mimicking the ZEBOV-specific RNA secondary structure were neither transcribed nor replicated. Mapping of the MARV genomic replication promoter revealed that the region homologous to the sequence involved in formation of the regulatory ZEBOV RNA structure is part of the MARV promoter. The MARV promoter is contained within the first 70 nucleotides of the genome and consists of two elements separated by a spacer region, comprising the TSS of the first gene. Mutations within the spacer abolished transcription activity and led to increased replication, indicating competitive transcription and replication initiation. The second promoter element is located within the nontranslated region of the first gene and consists of a stretch of three UN(5) hexamers. Recombinant full-length MARV clones, in which the three conserved U residues were substituted, could not be rescued, underlining the importance of the UN(5) hexamers for replication activity. Our data suggest that differences in the structure of the genomic replication promoters might account for the different transcription strategies of Marburg and Ebola viruses.
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Abstract
Genome synthesis in paramyxoviruses, including Nipah virus (NiV), is controlled by sequence elements that reside in the non-coding nucleotides at the 5'-trailer (3'-antigenomic) end that make up the antigenomic promoter (AGP). Using a chloramphenicol acetyl transferase-based plasmid-driven minigenome system, the terminal 96 nt of NiV AGP were first mutagenized in blocks of three hexamers to enable broad mapping of the minigenome functional regions. This was followed by further dissection of these functional regions to define the cis-acting elements contained therein. Results based on RNA analysis and reporter gene activity identified a bipartite promoter structure similar to that seen in related viruses, but with some distinct differences: in NiV, each of the two discrete replication control elements was bimodal, characterized by a critical conserved region (nt 1-12 and 79-91) and a contiguous non-conserved region (nt 13-36 and 73-78), which appeared less important. The regulatory role of these less critical regions was underscored by the use of a two-step mutation strategy, which revealed the additive detrimental effect of substitutions in this part of the terminal element. The structure and sequence characteristics of the internal control element was also different: it involved four contiguous hexamers, and the region encompassing three of these (nt 79-96, corresponding to hexamers 14, 15 and 16), although analogous in position to the equivalent element in the Sendai virus AGP, was characterized by the distinct 5'-(GNNNUG)(14-15)(GNNNNN)(16) motif.
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Affiliation(s)
- Pramila Walpita
- Departments of Pathology, and Microbiology and Immunology, Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, TX, USA
| | - Clarence J Peters
- Departments of Pathology, and Microbiology and Immunology, Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, TX, USA
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Hoffman MA, Thorson LM, Vickman JE, Anderson JS, May NA, Schweitzer MN. Roles of human parainfluenza virus type 3 bases 13 to 78 in replication and transcription: identification of an additional replication promoter element and evidence for internal transcription initiation. J Virol 2007; 80:5388-96. [PMID: 16699019 PMCID: PMC1472146 DOI: 10.1128/jvi.00204-06] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The genomic promoter of human parainfluenza virus type 3 (HPIV3) contains multiple cis-elements controlling transcription and replication. Previous work showed that regions 1 to 12 and 79 to 96 were critical in promoting replication of an HPIV3 minireplicon, while the intergenic sequence and N gene start signal (IS/Ngs, bases 49 to 61) were important for transcription. Because these data were collected primarily using point mutations, not every base from position 1 to 96 was analyzed, and some important control elements may have been missed. To clarify the role of bases 13 to 78 in transcription and replication, a series of mutations were made which collectively scanned this entire region. Mutation of bases 13 to 28 resulted in markedly decreased HPIV3 minireplicon replication, indicating these bases constitute an additional cis-element involved in the synthesis of the HPIV3 antigenomic RNA. The position dependence of the IS/Ngs was also examined. Analysis of mutants in which the IS/Ngs was shifted 5' or 3' showed that this segment could be moved without significantly disrupting transcription initiation. Additional mutants which contained two successive IS/Ngs segments were created to test whether the polymerase accessed the gene start signal by proceeding along the template 3' to 5' or by binding internally at the gene start signal. Based on analysis of the double gene start mutants, we propose a model of internal transcription initiation in which the polymerase enters the template at approximately the location of the natural N gene start but then scans the template bidirectionally to find a gene start signal and initiate transcription.
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Affiliation(s)
- Michael A Hoffman
- Department of Microbiology, University of Wisconsin-La Crosse, 1725 State Street, La Crosse, WI 54601, USA.
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Ujvári D. Complete nucleotide sequence of IT-227/82, an avian paramyxovirus type-1 strain of pigeons (Columba livia). Virus Genes 2006; 32:49-57. [PMID: 16525735 DOI: 10.1007/s11262-005-5845-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2005] [Accepted: 06/24/2005] [Indexed: 11/26/2022]
Abstract
This paper describes the complete genome sequence of IT-227/82, a strain of avian paramyxovirus type-1 of pigeon (PPMV-1). IT-227/82 is an antigenic variant of Newcastle disease virus (NDV) of chickens. The genome is 15,192 nucleotides (nt) long, similarly to the previously published NDV strain ZJ1. It is, however, six nt longer than the genomes of NDV strains LaSota/46 and Beaudette C. The six-nt insertion was located in the 5' non-coding region of the nucleoprotein (NP) gene. The presence of this six-nt insertion showed no correlation with the virulence or the reservoir of the NDV strains sequenced so far. The genome length of 15,186 or 15,192 nt can be connected however, to "old" (I, II, III and IV) and "new" (V, VI, VII and VIII) NDV genotypes, respectively. Comparison of open reading frames indicated that the PPMV-1 strain IT-227/82 encodes the longest W protein, (227 amino acids). The length of the W protein showed remarkable differences even within genotypes and cannot be regarded, therefore, as a phylogenetic feature. The haemagglutinin-neuraminidase protein of strain IT-227/82 consists of 571 amino acids, similarly to genotypes IV, V and VII NDV strains, while genotype I and II strains have longer HN proteins, 616 and 577 amino acids, respectively. The length of the haemagglutinin-neuraminidase protein possesses phylogenetic importance.
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Affiliation(s)
- Dorina Ujvári
- Veterinary Medical Research Institute, P.O. Box 18, 1581, Budapest, Hungary.
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Cordey S, Roux L. Transcribing paramyxovirus RNA polymerase engages the template at its 3′ extremity. J Gen Virol 2006; 87:665-672. [PMID: 16476989 DOI: 10.1099/vir.0.81353-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
For the non-segmented, negative-stranded RNA viruses, the mechanism controlling transcription or replication is still a matter of debate. To gain information about this mechanism and about the nature of the RNA polymerase involved, the length of an intervening sequence separating the 3′ end of Sendai virus minigenomes and a downstream transcription-initiation signal was increased progressively. It was found that transcription, as measured by green fluorescent protein (GFP) expression, decreased progressively in proportion to the increase in length of the intervening sequence. GFP expression correlated well with the levels of GFP mRNA in the cells, as measured by quantitative primer extension and by RNase protection. Thus, mRNA transcription was inversely proportional to the length of the inserted sequence. These data are evidence that the RNA polymerase initiating transcription at the downstream transcription signal somehow sees the distance separating this signal and the template 3′ extremity. Implication of this observation for the nature of the Sendai virus RNA polymerase and for the mechanism by which it synthesizes mRNAs or replication products is presented.
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Affiliation(s)
- Samuel Cordey
- Department of Microbiology and Molecular Medicine, University of Geneva Medical School, CMU, 1 rue Michel-Servet, CH-1211 Geneva 4, Switzerland
| | - Laurent Roux
- Department of Microbiology and Molecular Medicine, University of Geneva Medical School, CMU, 1 rue Michel-Servet, CH-1211 Geneva 4, Switzerland
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Weik M, Enterlein S, Schlenz K, Mühlberger E. The Ebola virus genomic replication promoter is bipartite and follows the rule of six. J Virol 2005; 79:10660-71. [PMID: 16051858 PMCID: PMC1182658 DOI: 10.1128/jvi.79.16.10660-10671.2005] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this work we investigated the cis-acting signals involved in replication of Ebola virus (EBOV) genomic RNA. A set of mingenomes with mutant 3' ends were generated and used in a reconstituted replication and transcription system. Our results suggest that the EBOV genomic replication promoter is bipartite, consisting of a first element located within the leader region of the genome and a second, downstream element separated by a spacer region. While proper spacing of the two promoter elements is a prerequisite for replication, the nucleotide sequence of the spacer is not important. Replication activity was only observed when six or a multiple of six nucleotides were deleted or inserted, while all other changes in length abolished replication completely. These data indicate that the EBOV replication promoter obeys the rule of six, although the genome length is not divisible by six. The second promoter element is located in the 3' nontranslated region of the first gene and consists of eight UN5 hexamer repeats, where N is any nucleotide. However, three consecutive hexamers, which could be located anywhere within the promoter element, were sufficient to support replication as long as the hexameric phase was preserved. By using chemical modification assays, we could demonstrate that nucleotides 5 to 44 of the EBOV leader are involved in the formation of a stable secondary structure. Formation of the RNA stem-loop occurred independently of the presence of the trailer, indicating that a panhandle structure is not formed between the 3' and 5' ends.
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Affiliation(s)
- Michael Weik
- Department of Virology, Philipps University Marburg, Robert-Koch-Str.17, 35037 Marburg, Germany
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