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Kleiner VA, Fearns R. How does the polymerase of non-segmented negative strand RNA viruses commit to transcription or genome replication? J Virol 2024:e0033224. [PMID: 39078194 DOI: 10.1128/jvi.00332-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/31/2024] Open
Abstract
The Mononegavirales, or non-segmented negative-sense RNA viruses (nsNSVs), includes significant human pathogens, such as respiratory syncytial virus, parainfluenza virus, measles virus, Ebola virus, and rabies virus. Although these viruses differ widely in their pathogenic properties, they are united by each having a genome consisting of a single strand of negative-sense RNA. Consistent with their shared genome structure, the nsNSVs have evolved similar ways to transcribe their genome into mRNAs and replicate it to produce new genomes. Importantly, both mRNA transcription and genome replication are performed by a single virus-encoded polymerase. A fundamental and intriguing question is: how does the nsNSV polymerase commit to being either an mRNA transcriptase or a replicase? The polymerase must become committed to one process or the other either before it interacts with the genome template or in its initial interactions with the promoter sequence at the 3´ end of the genomic RNA. This review examines the biochemical, molecular biology, and structural biology data regarding the first steps of transcription and RNA replication that have been gathered over several decades for different families of nsNSVs. These findings are discussed in relation to possible models that could explain how an nsNSV polymerase initiates and commits to either transcription or genome replication.
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Affiliation(s)
- Victoria A Kleiner
- Department of Virology, Immunology & Microbiology, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, USA
| | - Rachel Fearns
- Department of Virology, Immunology & Microbiology, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, USA
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Comparison of RNA synthesis initiation properties of non-segmented negative strand RNA virus polymerases. PLoS Pathog 2021; 17:e1010151. [PMID: 34914795 PMCID: PMC8717993 DOI: 10.1371/journal.ppat.1010151] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 12/30/2021] [Accepted: 11/26/2021] [Indexed: 11/19/2022] Open
Abstract
It is generally thought that the promoters of non-segmented, negative strand RNA viruses (nsNSVs) direct the polymerase to initiate RNA synthesis exclusively opposite the 3´ terminal nucleotide of the genome RNA by a de novo (primer independent) initiation mechanism. However, recent studies have revealed that there is diversity between different nsNSVs with pneumovirus promoters directing the polymerase to initiate at positions 1 and 3 of the genome, and ebolavirus polymerases being able to initiate at position 2 on the template. Studies with other RNA viruses have shown that polymerases that engage in de novo initiation opposite position 1 typically have structural features to stabilize the initiation complex and ensure efficient and accurate initiation. This raised the question of whether different nsNSV polymerases have evolved fundamentally different structural properties to facilitate initiation at different sites on their promoters. Here we examined the functional properties of polymerases of respiratory syncytial virus (RSV), a pneumovirus, human parainfluenza virus type 3 (PIV-3), a paramyxovirus, and Marburg virus (MARV), a filovirus, both on their cognate promoters and on promoters of other viruses. We found that in contrast to the RSV polymerase, which initiated at positions 1 and 3 of its promoter, the PIV-3 and MARV polymerases initiated exclusively at position 1 on their cognate promoters. However, all three polymerases could recognize and initiate from heterologous promoters, with the promoter sequence playing a key role in determining initiation site selection. In addition to examining de novo initiation, we also compared the ability of the RSV and PIV-3 polymerases to engage in back-priming, an activity in which the promoter template is folded into a secondary structure and nucleotides are added to the template 3´ end. This analysis showed that whereas the RSV polymerase was promiscuous in back-priming activity, the PIV-3 polymerase generated barely detectable levels of back-primed product, irrespective of promoter template sequence. Overall, this study shows that the polymerases from these three nsNSV families are fundamentally similar in their initiation properties, but have differences in their abilities to engage in back-priming.
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Bach S, Demper JC, Klemm P, Schlereth J, Lechner M, Schoen A, Kämper L, Weber F, Becker S, Biedenkopf N, Hartmann RK. Identification and characterization of short leader and trailer RNAs synthesized by the Ebola virus RNA polymerase. PLoS Pathog 2021; 17:e1010002. [PMID: 34699554 PMCID: PMC8547711 DOI: 10.1371/journal.ppat.1010002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 10/04/2021] [Indexed: 11/21/2022] Open
Abstract
Transcription of non-segmented negative sense (NNS) RNA viruses follows a stop-start mechanism and is thought to be initiated at the genome’s very 3’-end. The synthesis of short abortive leader transcripts (leaderRNAs) has been linked to transcription initiation for some NNS viruses. Here, we identified the synthesis of abortive leaderRNAs (as well as trailer RNAs) that are specifically initiated opposite to (anti)genome nt 2; leaderRNAs are predominantly terminated in the region of nt ~ 60–80. LeaderRNA synthesis requires hexamer phasing in the 3’-leader promoter. We determined a steady-state NP mRNA:leaderRNA ratio of ~10 to 30-fold at 48 h after Ebola virus (EBOV) infection, and this ratio was higher (70 to 190-fold) for minigenome-transfected cells. LeaderRNA initiation at nt 2 and the range of termination sites were not affected by structure and length variation between promoter elements 1 and 2, nor the presence or absence of VP30. Synthesis of leaderRNA is suppressed in the presence of VP30 and termination of leaderRNA is not mediated by cryptic gene end (GE) signals in the 3’-leader promoter. We further found different genomic 3’-end nucleotide requirements for transcription versus replication, suggesting that promoter recognition is different in the replication and transcription mode of the EBOV polymerase. We further provide evidence arguing against a potential role of EBOV leaderRNAs as effector molecules in innate immunity. Taken together, our findings are consistent with a model according to which leaderRNAs are abortive replicative RNAs whose synthesis is not linked to transcription initiation. Rather, replication and transcription complexes are proposed to independently initiate RNA synthesis at separate sites in the 3’-leader promoter, i.e., at the second nucleotide of the genome 3’-end and at the more internally positioned transcription start site preceding the first gene, respectively, as reported for Vesicular stomatitis virus. The RNA polymerase (RdRp) of Ebola virus (EBOV) initiates RNA synthesis at the 3’-leader promoter of its encapsidated, non-segmented negative sense (NNS) RNA genome, either at the penultimate 3’-end position of the genome in the replicative mode or more internally (position 56) at the transcription start site (TSS) in its transcription mode. Here we identified the synthesis of abortive replicative RNAs that are specifically initiated opposite to genome nt 2 (termed leaderRNAs) and predominantly terminated in the region of nt ~ 60–80 near the TSS. The functional role of abortive leaderRNA synthesis is still enigmatic; a role in interferon induction could be excluded. Our findings indirectly link leaderRNA termination to nucleoprotein (NP) availability for encapsidation of nascent replicative RNA or to NP removal from the template RNA. Our findings further argue against the model that leaderRNA synthesis is a prerequisite for each transcription initiation event at the TSS. Rather, our findings are in line with the existence of distinct replicase and transcriptase complexes of RdRp that interact differently with the 3’-leader promoter and intiate RNA synthesis independently at different sites (position 2 or 56 of the genome), mechanistically similar to another NNS virus, Vesicular stomatitis virus.
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Affiliation(s)
- Simone Bach
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marburg, Germany
| | - Jana-Christin Demper
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marburg, Germany
| | - Paul Klemm
- Zentrum für Synthetische Mikrobiologie, Philipps-Universität Marburg, Marburg, Germany
| | - Julia Schlereth
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marburg, Germany
| | - Marcus Lechner
- Zentrum für Synthetische Mikrobiologie, Philipps-Universität Marburg, Marburg, Germany
| | - Andreas Schoen
- Institut für Virologie, Justus-Liebig-Universität Gießen, Gießen, Germany
| | - Lennart Kämper
- Institut für Virologie, Philipps-Universität Marburg, Marburg, Germany
| | - Friedemann Weber
- Institut für Virologie, Justus-Liebig-Universität Gießen, Gießen, Germany
| | - Stephan Becker
- Institut für Virologie, Philipps-Universität Marburg, Marburg, Germany
| | - Nadine Biedenkopf
- Institut für Virologie, Philipps-Universität Marburg, Marburg, Germany
- * E-mail: (NB); (RKH)
| | - Roland K. Hartmann
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marburg, Germany
- * E-mail: (NB); (RKH)
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Cheng Q, Huai W, Wu X, Chen M. Sumoylation of Human Parainfluenza Virus Type 3 Phosphoprotein Correlates with A Reduction in Viral Replication. Virol Sin 2020; 36:438-448. [PMID: 33197004 DOI: 10.1007/s12250-020-00314-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 09/29/2020] [Indexed: 10/23/2022] Open
Abstract
Human parainfluenza virus type 3 (HPIV3), a member of the Paramyxoviridae family, can cause lower respiratory disease in infants and young children. The phosphoprotein (P) of HPIV3 is an essential cofactor of the viral RNA-dependent RNA polymerase large protein (L). P connects nucleocapsid protein (N) with L to initiate genome transcription and replication. Sumoylation influences many important pathways of the target proteins, and many viral proteins are also themselves sumoylated. In this study, we found that the P of HPIV3 could be sumoylated, and mutation of K492 and K532 to arginine (PK492R/K532R) failed to be sumoylated within P, which enhances HPIV3 minigenome activity. Biochemical studies showed that PK492R/K532R had no effect on its interactions with N, formation of homo-tetramers and formation of inclusion bodies. Finally, we found that incorporation of K492R/K532R into a recombinant HPIV3 (rHPIV3-PK492R/K532R) increased viral production in culture cells, suggesting that sumoylation attenuates functions of P and down-regulates viral replication.
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Affiliation(s)
- Qi Cheng
- State Key Laboratory of Virology, Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Wenjing Huai
- State Key Laboratory of Virology, Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Xiaoyan Wu
- State Key Laboratory of Virology, Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Mingzhou Chen
- State Key Laboratory of Virology, Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
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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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Structure of a paramyxovirus polymerase complex reveals a unique methyltransferase-CTD conformation. Proc Natl Acad Sci U S A 2020; 117:4931-4941. [PMID: 32075920 PMCID: PMC7060699 DOI: 10.1073/pnas.1919837117] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Paramyxoviruses are enveloped, nonsegmented, negative-strand RNA viruses that cause a wide spectrum of human and animal diseases. The viral genome, packaged by the nucleoprotein (N), serves as a template for the polymerase complex, composed of the large protein (L) and the homo-tetrameric phosphoprotein (P). The ∼250-kDa L possesses all enzymatic activities necessary for its function but requires P in vivo. Structural information is available for individual P domains from different paramyxoviruses, but how P interacts with L and how that affects the activity of L is largely unknown due to the lack of high-resolution structures of this complex in this viral family. In this study we determined the structure of the L-P complex from parainfluenza virus 5 (PIV5) at 4.3-Å resolution using cryoelectron microscopy, as well as the oligomerization domain (OD) of P at 1.4-Å resolution using X-ray crystallography. P-OD associates with the RNA-dependent RNA polymerase domain of L and protrudes away from it, while the X domain of one chain of P is bound near the L nucleotide entry site. The methyltransferase (MTase) domain and the C-terminal domain (CTD) of L adopt a unique conformation, positioning the MTase active site immediately above the poly-ribonucleotidyltransferase domain and near the likely exit site for the product RNA 5' end. Our study reveals a potential mechanism that mononegavirus polymerases may employ to switch between transcription and genome replication. This knowledge will assist in the design and development of antivirals against paramyxoviruses.
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Noton SL, Tremaglio CZ, Fearns R. Killing two birds with one stone: How the respiratory syncytial virus polymerase initiates transcription and replication. PLoS Pathog 2019; 15:e1007548. [PMID: 30817806 PMCID: PMC6394897 DOI: 10.1371/journal.ppat.1007548] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Affiliation(s)
- Sarah L. Noton
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Chadene Z. Tremaglio
- Department of Biology, University of Saint Joseph, West Hartford, Connecticut, United States of America
| | - Rachel Fearns
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail:
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Human Parainfluenza Virus Type 3 Matrix Protein Reduces Viral RNA Synthesis of HPIV3 by Regulating Inclusion Body Formation. Viruses 2018. [PMID: 29534486 PMCID: PMC5869518 DOI: 10.3390/v10030125] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Human parainfluenza virus type 3 is one of the main causes of lower respiratory illness in newborns and infants. The role of the matrix protein (M) in viral budding is extensively studied, but the effect of M on viral replication remains to be determined. Using an HPIV3 minigenome assay, we found that M reduced HPIV3 mingenome-encoded reporter activity even though it had an unspecific effect on the expression of cellular genes. Furthermore, the inhibition effect of M on viral RNA synthesis was proven to be independent of its virus-like particles (VLPs)' release ability. A VLP's defective mutant (ML302A) decreased the expression of minigenome reporter as wild type M did. Using an immunofluorescence assay, we found that M weakened the formation of inclusion bodies (IBs), although it did not co-localize with the IBs. Moreover, using another mutant, ML305A , which is defective in M-nucleoprotein (N) interaction, we found that ML305A had no effect on reporter activity and IB formation as the wild type of M did. Taken together, we conclude that M reduces the replication of HPIV3 and IB formation by M-N interaction.
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Hu Z, Wang Y, Tang Q, Yang X, Qin Y, Chen M. Inclusion bodies of human parainfluenza virus type 3 inhibit antiviral stress granule formation by shielding viral RNAs. PLoS Pathog 2018. [PMID: 29518158 PMCID: PMC5860793 DOI: 10.1371/journal.ppat.1006948] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Viral invasion triggers the activation of the host antiviral response. Besides the innate immune response, stress granules (SGs) also act as an additional defense response to combat viral replication. However, many viruses have evolved various strategies to suppress SG formation to facilitate their own replication. Here, we show that viral mRNAs derived from human parainfluenza virus type 3 (HPIV3) infection induce SG formation in an eIF2α phosphorylation- and PKR-dependent manner in which viral mRNAs are sequestered and viral replication is inhibited independent of the interferon signaling pathway. Furthermore, we found that inclusion body (IB) formation by the interaction of the nucleoprotein (N) and phosphoprotein (P) of HPIV3 correlated with SG suppression. In addition, co-expression of P with NL478A (a point mutant of N, which is unable to form IBs with P) or with NΔN10 (lacking N-terminal 10 amino acids of N, which could form IBs with P but was unable to synthesize or shield viral RNAs) failed to inhibit SG formation, suggesting that inhibition of SG formation also correlates with the capacity of IBs to synthesize and shield viral RNAs. Therefore, we provide a model whereby viral IBs escape the antiviral effect of SGs by concealing their own newly synthesized viral RNAs and offer new insights into the emerging role of IBs in viral replication. Human parainfluenza virus type 3 (HPIV3) is one of the major causes of acute respiratory tract diseases such as pneumonia and bronchitis in infants and children. Virus invasion activates cellular stress responses. One of these responses is the formation of SGs which counteract viral replication. However, many viruses have evolved various strategies to suppress SG formation, thus facilitating their own replication. We sought to determine if (and how) HPIV3 modulates SG formation to facilitate its replication and found that the viral messenger RNAs (mRNAs) of HPIV3 trigger SG formation in infected cells. As time increased post-infection, the number of cells containing SGs increased as well. To escape this response, HPIV3 forms IBs that shield viral RNAs, thereby preventing SG formation and allowing the virus to replicate and survive—and potentially invade other cells.
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Affiliation(s)
- Zhulong Hu
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, LuoJia Hill, Wuhan, China
| | - Yuang Wang
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, LuoJia Hill, Wuhan, China
| | - Qiaopeng Tang
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, LuoJia Hill, Wuhan, China
| | - Xiaodan Yang
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, LuoJia Hill, Wuhan, China
| | - Yali Qin
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, LuoJia Hill, Wuhan, China
| | - Mingzhou Chen
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, LuoJia Hill, Wuhan, China
- * E-mail:
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Zhang S, Cheng Q, Luo C, Yin L, Qin Y, Chen M. An alanine residue in human parainfluenza virus type 3 phosphoprotein is critical for restricting excessive N 0-P interaction and maintaining N solubility. Virology 2018; 518:64-76. [PMID: 29455063 DOI: 10.1016/j.virol.2018.02.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 01/09/2018] [Accepted: 02/06/2018] [Indexed: 10/18/2022]
Abstract
The phosphoprotein (P) of human parainfluenza virus type 3 (HPIV3) plays a pivotal role in viral RNA synthesis, which interacts with the nucleoprotein (N) to form a soluble N0-P complex (N0, free of RNAs) to prevent the nonspecific RNA binding and illegitimate aggregation of N. Functional regions within P have been studied intensively. However, the precise site (s) within P directly involved in N0-P interaction still remains unclear. In this study, using a series of deleted and truncated mutants of P of HPIV3, we demonstrate that amino-terminal 40 amino acids (aa) of P restrict and regulate N0-P interaction. Furthermore, using in vivo HPIV3 minigenome replicon assay, we identify a critical P mutant (PA28P) located in amino-terminal 40 aa, which fails to support RNA synthesis of HPIV3 minigenome replicon. Although PA28P maintains an enhanced N-P interaction, it is unable to form N0-P complex and keep N soluble, thus, resulting in aggregation and functional abolishment of N-P complex. Moreover, we found that recombinant HPIV3 with mutation of A28P in P failed to be rescued. Taken together, we identified a residue within the extreme amino-terminus of P, which plays a critical role in restricting the excessively N-P interaction and keeping a functional N0-P complex formation.
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Affiliation(s)
- Shengwei Zhang
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, China; Hubei University of Chinese Medicine, School of Laboratory Medicine, Wuhan, China
| | - Qi Cheng
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, China
| | - Chenxi Luo
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, China
| | - Lei Yin
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yali Qin
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, China.
| | - Mingzhou Chen
- State Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan, China.
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A Point Mutation in the RNA-Binding Domain of Human Parainfluenza Virus Type 2 Nucleoprotein Elicits Abnormally Enhanced Polymerase Activity. J Virol 2017; 91:JVI.02203-16. [PMID: 28179533 DOI: 10.1128/jvi.02203-16] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 02/06/2017] [Indexed: 11/20/2022] Open
Abstract
The genome RNA of human parainfluenza virus type 2 (hPIV2) that acts as the template for the polymerase complex is entirely encapsidated by the nucleoprotein (NP). Recently, the crystal structure of NP of PIV5, a virus closely related to hPIV2, was resolved in association with RNA. Ten amino acids that contact the bound RNA were identified and are strictly conserved between PIV5 and hPIV2 NP. Mutation of hPIV2 NP Q202 (which contacts a base rather than the RNA backbone) to various amino acids resulted in an over 30-fold increase of polymerase activity as evidenced by a minireplicon assay, even though the RNA-binding affinity was unaltered. Using various modified minireplicons, we found that the enhanced reporter gene expression could be accounted for by increased minigenome replication, whereas mRNA synthesis itself was not affected by Q202 mutation. Moreover, the enhanced activities were still observed in minigenomes partially lacking the leader sequence and which were not of hexamer genome length. Unexpectedly, recombinant hPIV2 possessing the NP Q202A mutation could not be recovered from cDNA.IMPORTANCE We examined the importance of amino acids in the putative RNA-binding domain of hPIV2 NP for polymerase activity using minireplicons. Abnormally enhanced genome replication was observed upon substitution mutation of the NP Q202 position to various amino acids. Surprisingly, this mutation enabled polymerase to use minigenomes that were partially lacking the leader sequence and not of hexamer genome length. This mutation does not affect fundamental properties of NP, e.g., recognition of gene junctional and editing signals. However, the strongly enhanced polymerase activity may not be viable for the infectious life cycle. This report highlights the potential of the polymerase complex with point mutations in NP and helps our detailed understanding of the molecular basis of gene expression.
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Inclusion Body Fusion of Human Parainfluenza Virus Type 3 Regulated by Acetylated α-Tubulin Enhances Viral Replication. J Virol 2017; 91:JVI.01802-16. [PMID: 27881643 DOI: 10.1128/jvi.01802-16] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 11/13/2016] [Indexed: 12/18/2022] Open
Abstract
Viral inclusion bodies (IBs), or replication factories, are unique structures generated by viral proteins together with some cellular proteins as a platform for efficient viral replication, but little is known about the mechanism underlying IB formation and fusion. Our previous study demonstrated that the interaction between the nucleoprotein (N) and phosphoprotein (P) of human parainfluenza virus type 3 (HPIV3), an enveloped virus with great medical impact, can form IBs. In this study, we found that small IBs can fuse with each other to form large IBs that enhance viral replication. Furthermore, we found that acetylated α-tubulin interacts with the N-P complex and colocalizes with IBs of HPIV3 but does not interact with the N-P complex of human respiratory syncytial virus or vesicular stomatitis virus and does not colocalize with IBs of human respiratory syncytial virus. Most importantly, enhancement of α-tubulin acetylation using the pharmacological inhibitor trichostatin A (TSA), RNA interference (RNAi) knockdown of the deacetylase enzymes histone deacetylase 6 (HDAC6) and sirtuin 2 (SIRT2), or expression of α-tubulin acetyltransferase 1 (α-TAT1) resulted in the fusion of small IBs into large IBs and effective viral replication. In contrast, suppression of acetylation of α-tubulin by overexpressing HDAC6 and SIRT2 profoundly inhibited the fusion of small IBs and viral replication. Our findings offer previously unidentified mechanistic insights into the regulation of viral IB fusion by acetylated α-tubulin, which is critical for viral replication. IMPORTANCE Inclusion bodies (IBs) are unique structures generated by viral proteins and some cellular proteins as a platform for efficient viral replication. Human parainfluenza virus type 3 (HPIV3) is a nonsegmented single-stranded RNA virus that mainly causes lower respiratory tract disease in infants and young children. However, no vaccines or antiviral drugs for HPIV3 are available. Therefore, understanding virus-host interactions and developing new antiviral strategies are increasingly important. Acetylation on lysine (K) 40 of α-tubulin is an evolutionarily conserved modification and plays an important role in many cellular processes, but its role in viral IB dynamics has not been fully explored. To our knowledge, our findings are the first to show that acetylated α-tubulin enhances viral replication by regulating HPIV3 IB fusion.
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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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14
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Mechanisms of temperature sensitivity of attenuated Urabe mumps virus. Virus Res 2016; 227:104-109. [PMID: 27720824 DOI: 10.1016/j.virusres.2016.10.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 10/04/2016] [Accepted: 10/05/2016] [Indexed: 11/23/2022]
Abstract
Temperature sensitivity is a phenotype often associated with attenuation of viruses. Previously, we purified several mumps variants from an incompletely attenuated Urabe strain live attenuated vaccine. Here we characterize one isolate that is sensitive to growth at high temperature. This virus was attenuated in a small animal model of mumps virulence, and we identified unique coding substitutions in the hemagglutinin-neuraminidase (HN), the viral polymerase (L) gene, and a non-coding substitution close to the anti-genome promoter sequences. At the non-permissive temperature, transcription of viral mRNAs and production of the replication intermediate were reduced compared to events at the permissive temperature and to a non-ts virulent Urabe virus. As well, synthesis of viral proteins was also reduced at the higher temperature. While the actual sequence substitutions in the ts virus were unique, the pattern of substitutions in HN, L and genome end sequences is similar to another attenuated Urabe virus previously described by us.
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15
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Kolakofsky D. Paramyxovirus RNA synthesis, mRNA editing, and genome hexamer phase: A review. Virology 2016; 498:94-98. [PMID: 27567257 DOI: 10.1016/j.virol.2016.08.018] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 08/11/2016] [Accepted: 08/18/2016] [Indexed: 11/17/2022]
Abstract
The recent flurry of high resolution structures of Negative Strand RNA Virus RNA-dependent RNA polymerases has rekindled interest in the manner in which these polymerases, and in particular those of the nonsegmented viruses, recognize the RNA sequences that control mRNA synthesis and genome replication. In the light of these polymerase structures, we re-examine some unusual aspects of the Paramyxoviridae, namely bipartite replication promoters and mRNA editing, and the manner in which these properties are governed by genome hexamer phase.
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Affiliation(s)
- Daniel Kolakofsky
- Department of Microbiology and Molecular Medicine, University of Geneva School of Medicine, Geneva, Switzerland.
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16
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Parainfluenza virus chimeric mini-replicons indicate a novel regulatory element in the leader promoter. J Gen Virol 2016; 97:1520-1530. [DOI: 10.1099/jgv.0.000479] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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17
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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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18
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An amino acid of human parainfluenza virus type 3 nucleoprotein is critical for template function and cytoplasmic inclusion body formation. J Virol 2013; 87:12457-70. [PMID: 24027324 DOI: 10.1128/jvi.01565-13] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The nucleoprotein (N) and phosphoprotein (P) interaction of nonsegmented negative-strand RNA viruses is essential for viral replication; this includes N⁰-P (N⁰, free of RNA) interaction and the interaction of N-RNA with P. The precise site(s) within N that mediates the N-P interaction and the detailed regulating mechanism, however, are less clear. Using a human parainfluenza virus type 3 (HPIV3) minigenome assay, we found that an N mutant (N(L478A) did not support reporter gene expression. Using in vivo and in vitro coimmunoprecipitation, we found that N(L478A) maintains the ability to form N(L478A)⁰-P, to self-assemble, and to form N(L478A)-RNA but that N(L478A)-RNA does not interact with P. Using an immunofluorescence assay, we found that N-P interaction provides the minimal requirement for the formation of cytoplasmic inclusion bodies, which contain viral RNA, N, P, and polymerase in HPIV3-infected cells. N(L478A) was unable to form inclusion bodies when coexpressed with P, but the presence of N rescued the ability of N(L478A) to form inclusion bodies and the transcriptional function of N(L478A), thereby suggesting that hetero-oligomers formed by N and N(L478A) are functional and competent to form inclusion bodies. Furthermore, we found that N(L478A) is also defective in virus growth. To our knowledge, we are the first to use a paramyxovirus to identify a precise amino acid within N that is critical for N-RNA and P interaction but not for N(0)-P interaction for the formation of inclusion bodies, which appear to be bona fide sites of RNA synthesis.
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19
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Gander JR, Schwan LM, Hoffman MA. Analysis of nucleotides 13-96 of the human parainfluenza virus type 3 antigenomic promoter reveals positive- and negative-acting replication elements. Virology 2011; 419:90-6. [PMID: 21880340 DOI: 10.1016/j.virol.2011.08.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 06/27/2011] [Accepted: 08/08/2011] [Indexed: 10/17/2022]
Abstract
During replication of human parainfluenza virus type 3 (HPIV3), the 96-nucleotide antigenomic promoter (AGP) of HPIV3 directs the synthesis of genomic RNA. Previous work showed that nucleotides 1-12 were critical in promoting replication of an HPIV3 minireplicon, but nucleotides 13-96 were not investigated. In this study, the role of nucleotides 13-96 in AGP function was analyzed by creating and assaying mutations in an HPIV3 minireplicon. A replication promoting element known as promoter element II (nt 79-96) was confirmed in the HPIV3 AGP. Additionally, nucleotides 13-39 were found to constitute an additional positive-acting cis-element. However, detailed analysis of the 13-39 element revealed a complicated control element with both stimulatory and repressing elements. Specifically, nucleotides 21-28 were shown to repress RNA replication, while flanking sequences had a stimulatory effect.
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Affiliation(s)
- Jill R Gander
- Department of Microbiology, University of Wisconsin-La Crosse, La Crosse, WI 54601, USA
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20
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Imai C, Fujita K, Shimizu F, Sugai A, Yoneda M, Kai C. Comparative and mutational analyses of promoter regions of rinderpest virus. Virology 2009; 396:169-77. [PMID: 19913269 DOI: 10.1016/j.virol.2009.10.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Revised: 04/21/2009] [Accepted: 10/12/2009] [Indexed: 10/20/2022]
Abstract
Comparative and mutational analysis of promoter regions of rinderpest virus was conducted. Minigenomic RNAs harboring the genomic and antigenomic promoter of the lapinized virulent strain (Lv) or an attenuated vaccine strain (RBOK) were constructed, and the expression of the reporter gene was examined. The activities of the antigenomic promoters of these strains were similar, whereas the activity of the genomic promoter (GP) of the RBOK strain was significantly higher than that of the Lv strain, regardless of cell type and the source of the N, P and L proteins. Increased replication (and/or encapsidation) activities were observed in the minigenomes that contained RBOK GP. Mutational analysis revealed that the nucleotides specific to the RBOK strain are responsible for the strong GP activity of the strain. It was also demonstrated that other virulent strains of RPV (Kabete O, Saudi/81 and Kuwait 82/1) have weaker GPs than that of the RBOK strain.
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Affiliation(s)
- Chieko Imai
- Laboratory Animal Research Center, The Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
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21
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Mao H, Chattopadhyay S, Banerjee AK. N-terminally truncated C protein, CNDelta25, of human parainfluenza virus type 3 is a potent inhibitor of viral replication. Virology 2009; 394:143-8. [PMID: 19747707 DOI: 10.1016/j.virol.2009.08.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2009] [Revised: 07/06/2009] [Accepted: 08/18/2009] [Indexed: 11/27/2022]
Abstract
The C protein of human parainfluenza virus type 3 (HPIV3) is a multifunctional accessory protein that inhibits viral transcription and interferon (IFN) signaling. In the present study, we found that removal of N-terminal 25 or 50 amino acid residues from the C protein (CNDelta25 or CNDelta50) totally abolished viral RNA synthesis in the HPIV3 minigenome system. Further N-terminal or C-terminal deletion impaired the inhibitory ability of CNDelta25 and CNDelta50. Subsequent mutagenesis analysis suggested that the N-terminal-charged amino acid residues (K3, K6, K12, E16, and R24) contribute to the higher inhibition caused by CNDelta25 than the C protein. Consistent with viral RNA synthesis inhibition, the growth of HPIV3 was significantly decreased by 5 logs in HeLa-derived cell line expressing CNDelta25. Interestingly, replication of respiratory syncytial virus (RSV), another important respiratory tract pathogen, was also strongly inhibited in the presence of CNDelta25. These findings provide a promising potential to use CNDelta25 as an antiviral agent against the clinically important respiratory tract diseases caused by HPIV3 and RSV.
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Affiliation(s)
- Hongxia Mao
- Virology Section, Department of Molecular Genetics, Lerner Research Institute, Cleveland Clinic Foundation, NN1-06, 9500 Euclid Avenue, Cleveland, OH 44195, USA
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22
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Role for the paramyxovirus genomic promoter in limiting host cell antiviral responses and cell killing. J Virol 2009; 83:9057-67. [PMID: 19587032 DOI: 10.1128/jvi.01055-09] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The parainfluenza virus simian virus 5 (SV5) is a poor inducer of innate immune responses. In contrast, the naturally occurring SV5 variant Wake Forest parainfluenza virus (WF-PIV) activates the synthesis of proinflammatory cytokines and beta interferon (IFN-beta). Comparison of SV5 and WF-PIV genome sequences revealed nine nucleotide differences within the viral genomic promoter, including two substitutions (U5C and A14G) in the most highly conserved 3'-end promoter element. To test the consequences of these promoter variations, a recombinant SV5 mutant [Le-(U5C, A14G)] was engineered to harbor the two WF-PIV genomic promoter substitutions in an otherwise wild-type (WT) SV5 background. Human lung epithelial cells infected with the Le-(U5C, A14G) mutant had higher rates of viral protein synthesis and levels of mRNA than cells infected with WT SV5, but levels of genomic RNA were not changed. Unlike WT SV5, the Le-(U5C, A14G) mutant was a potent inducer of interleukin-6 and IFN-beta synthesis, despite expressing a functional V protein antagonist. Cytokine responses to Le-(U5C, A14G) infection were reduced either by small interfering RNA-mediated knockdown of retinoic acid-inducible gene I (RIG-I) or after infection of cells that were engineered to express the reovirus sigma3 double-stranded RNA-binding protein. Le-(U5C, A14G) induced cytopathic effects not seen with WT SV5, and the extent of cell killing correlated with elevated levels of viral F protein and cell-cell fusion. Our results support a model whereby the SV5 promoter has evolved to function at an attenuated level in order to limit (i) synthesis of aberrant RNAs which induce RIG-I-mediated responses and (ii) overproduction of mRNA for potentially toxic gene products, such as the F protein. Control of genomic promoter activity may be particularly important for viruses such as SV5, that express a V protein targeting mda-5 but do not encode antagonists such as the paramyxovirus C proteins, that specifically target RIG-I.
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23
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Malur AG, Wells G, McCoy A, Banerjee AK. Evidence for phosphorylation of human parainfluenza virus type 3 C protein: mutant C proteins exhibit variable inhibitory activities in vitro. Virus Res 2009; 144:180-7. [PMID: 19410612 DOI: 10.1016/j.virusres.2009.04.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Revised: 04/16/2009] [Accepted: 04/26/2009] [Indexed: 11/16/2022]
Abstract
The P mRNA of human parainfluenza virus type 3, like other members of the subfamily Paramyxovirinae, gives rise to several polypeptides, one amongst them, the C protein, which is involved in inhibition of viral RNA synthesis as well as counteracting the host interferon signaling pathway. As a further step towards characterizing the function of C protein we present evidence to demonstrate the phosphorylation of C protein. Evidence for this observation emerged from deletion mapping studies coupled with mass spectroscopy analysis confirming residues S7, S22, S47T48 and S81 residues as the phosphorylation sites within the NH(2)-terminus of C protein. Here, we utilized a HPIV 3 minigenome replication assay and real time RT-PCR analysis to measure the relative RNA levels synthesized in the presence of mutant C proteins. Mutants S7A and S81A displayed low levels of RNA while mutant 5A that was devoid of all these phosphorylation sites exhibited high RNA level in comparison to wild type C during transcription. Interestingly, high levels of RNA were observed in the presence of S81A and mutant 5A during replication. Taken together, our results indicate that phosphorylation may differentially affect the inhibitory activity of C protein thereby regulating viral RNA synthesis.
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Affiliation(s)
- Achut G Malur
- Department of Microbiology and Immunology, Brody School of Medicine, Biotech 124, East Carolina University, 600 Moye Boulevard, Greenville, NC 27834, USA.
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24
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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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25
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Chattopadhyay S, Banerjee AK. Phosphoprotein, P of human parainfluenza virus type 3 prevents self-association of RNA-dependent RNA polymerase, L. Virology 2008; 383:226-36. [PMID: 19012944 DOI: 10.1016/j.virol.2008.10.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Revised: 08/22/2008] [Accepted: 10/13/2008] [Indexed: 10/21/2022]
Abstract
The RNA-dependent RNA-polymerase (RdRp) of human parainfluenza virus type 3 (HPIV3) is a large protein (L, 2233 amino acids), and along with the phosphoprotein (P, 603 amino acids) forms a heterocomplex that transcribes the genome RNA into mRNAs in vitro and in vivo that are 5'-capped and methylated and 3'-polyadenylated. The interaction of the P protein, an obligatory cofactor, imparts the RdRp activity of the L protein, which is otherwise inactive. The precise mechanism underlying this activation process remains unknown. Several recent reports suggested that the L proteins of paramyxoviruses, when expressed alone, self-associate to form an oligomeric structure. The presumptive oligomerization domain lies in the N-terminal part of the L protein (for HPIV3, 889 amino acids). Here, we demonstrate that a series of N-terminally deleted L proteins as well as several truncated proteins that span different regions of the L protein can also efficiently co-immunoprecipitate the full length L protein. In addition, by several biochemical parameters, the L-L interaction was shown to form aggregates rather than oligomers. In contrast, when the P protein was co-expressed with the L protein, the former bound to a domain spanning the N-terminal 1060 amino acids of the latter, which prevented L-L self-association, resulting in the formation of structurally competent and functionally active RdRp.
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Affiliation(s)
- Santanu Chattopadhyay
- Department of Molecular Genetics, Section of Virology, Lerner Research Institute, The Cleveland Clinic, Cleveland, OH 44195, USA
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26
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Mao H, Thakur CS, Chattopadhyay S, Silverman RH, Gudkov A, Banerjee AK. Inhibition of human parainfluenza virus type 3 infection by novel small molecules. Antiviral Res 2007; 77:83-94. [PMID: 17964670 DOI: 10.1016/j.antiviral.2007.09.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2007] [Revised: 08/31/2007] [Accepted: 09/04/2007] [Indexed: 01/07/2023]
Abstract
Human parainfluenza virus type 3 (HPIV3) is an important respiratory tract pathogen of infants and children. There are no vaccines or antivirals currently approved for prevention or treatment of HPIV3 infection. Towards developing an antiviral therapy to combat HPIV3 infection, we have established a green fluorescent protein (GFP)-tagged HPIV3 infected-cell assay and used it for screening of a small molecule library obtained from ChemBridge Diver. Two novel small molecules (C5 and C7) which shared structural similarities were identified and their inhibitory effects on HPIV3 were confirmed in CV-1 and human lung epithelium A549 cells by plaque assay, Western blot and Northern blot analyses. C5 and C7 effectively prevented the cytopathic effect in cells infected with HPIV3, achieving IC(50) values of 2.36 microM and 0.08 microM, respectively, for infectious virus production. The inhibition appears to be at the primary transcriptional level of HPIV3 life cycle based on sequential time course test, binding and internalization assays, and finally by a minigenome transcription assay in cells as well as measuring viral transcripts in cells in the presence of anisomycin. Interestingly, vesicular stomatitis virus (VSV), another member of mononegavirales order, was also inhibited by these compounds, whereas poliovirus-a picornavirus was not. Use of these inhibitors has a strong potential to develop novel antiviral agents against this important human pathogen.
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Affiliation(s)
- Hongxia Mao
- Department of Molecular Genetics, Virology Section NN10, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
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27
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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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28
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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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29
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Liu X, Bankamp B, Xu W, Bellini WJ, Rota PA. The genomic termini of wild-type and vaccine strains of measles virus. Virus Res 2006; 122:78-84. [PMID: 16889863 DOI: 10.1016/j.virusres.2006.06.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2006] [Revised: 06/15/2006] [Accepted: 06/28/2006] [Indexed: 11/23/2022]
Abstract
The genomic termini from 18 strains of measles virus (MV) including wild-type MVs from the pre-vaccine period, recent wild-type isolates and various vaccine strains were sequenced. The first 25 nucleotides of the 3' terminus and last 52 nucleotides of the 5' terminus were conserved in all of the viruses examined. Nucleotides 26 and 42 of the 3' leader were A and G, respectively, in all genotype A viruses except Edmonston wild-type (Ed-WT). All non-genotype A viruses and Ed-WT had U in both positions. No consistent substitution pattern was found in the 5' trailer region of the genome. The nucleotide substitutions at positions 26 and 42 in the 3' leader region were introduced into a MV-CAT mini-genome to test for their effect on the production of reporter protein in both a vaccinia T7-driven, plasmid-based replication assay as well as in a helper virus system. Regardless of the source of the polymerase proteins or the natural leader sequence of the helper viruses, the mini-genome 26A42G produced more CAT protein than 26U42U. The nucleotide substitution at 26 had the greatest effect on CAT production. These results indicated that naturally occurring nucleotide variations in the 3' leader region can affect the levels of reporter protein synthesis, and presumably affected the level of replication of the virus.
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Affiliation(s)
- Xin Liu
- Measles, Mumps, Rubella and Herpesvirus Branch, Centers for Disease Control and Prevention, MS-C-22, 1600 Clifton Rd., Atlanta, GA 30333, USA
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30
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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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31
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Cowton VM, Fearns R. Evidence that the respiratory syncytial virus polymerase is recruited to nucleotides 1 to 11 at the 3' end of the nucleocapsid and can scan to access internal signals. J Virol 2005; 79:11311-22. [PMID: 16103183 PMCID: PMC1193587 DOI: 10.1128/jvi.79.17.11311-11322.2005] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The 3'-terminal end of the respiratory syncytial virus genomic RNA contains a 44-nucleotide leader (Le) region adjoining the gene start signal of the first gene. Previous mapping studies demonstrated that there is a promoter located at the 3' end of Le, which can signal initiation of antigenome synthesis. The aim of this study was to investigate the role of the 3' terminus of the RNA template in (i) promoter recognition and (ii) determining the initiation site for antigenome synthesis. A panel of minigenomes containing additional sequence at the 3' end of the Le were analyzed for their ability to direct antigenome and mRNA synthesis. Minigenomes containing heterologous extensions of 6 nucleotides or more were unable to support efficient RNA synthesis. However, the activity of a minigenome with a 56-nucleotide extension could be restored by insertion of Le nucleotides 1 to 11 or 1 to 13 at the 3' end, indicating that these nucleotides, in conjunction with the 3' terminus, are sufficient to recruit polymerase to the template. Northern blot and 5' rapid amplification of cDNA ends analysis of antigenome RNA indicated that antigenome initiation occurred at the first position of Le, irrespective of the terminal extension. This finding demonstrates that the 3' terminus of the RNA is not necessary for determining the antigenome initiation site. Data are presented which suggest that following recruitment to a promoter at the 3' end of Le, the polymerase is able to scan and respond to a promoter signal embedded within the RNA template.
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Affiliation(s)
- Vanessa M Cowton
- Division of Pathology and Neuroscience, University of Dundee, UK
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32
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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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33
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Kolakofsky D, Roux L, Garcin D, Ruigrok RWH. Paramyxovirus mRNA editing, the "rule of six" and error catastrophe: a hypothesis. J Gen Virol 2005; 86:1869-1877. [PMID: 15958664 DOI: 10.1099/vir.0.80986-0] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The order Mononegavirales includes three virus families that replicate in the cytoplasm: the Paramyxoviridae, composed of two subfamilies, the Paramyxovirinae and Pneumovirinae, the Rhabdoviridae and the Filoviridae. These viruses, also called non-segmented negative-strand RNA viruses (NNV), contain five to ten tandemly linked genes, which are separated by conserved junctional sequences that act as mRNA start and poly(A)/stop sites. For the NNV, downstream mRNA synthesis depends on termination of the upstream mRNA, and all NNV RNA-dependent RNA polymerases reiteratively copy ("stutter" on) a short run of template uridylates during transcription to polyadenylate and terminate their mRNAs. The RNA-dependent RNA polymerase of a subset of the NNV, all members of the Paramyxovirinae, also stutter in a very controlled fashion to edit their phosphoprotein gene mRNA, and Ebola virus, a filovirus, carries out a related process on its glycoprotein mRNA. Remarkably, all viruses that edit their phosphoprotein mRNA are also governed by the "rule of six", i.e. their genomes must be of polyhexameric length (6n+0) to replicate efficiently. Why these two seemingly unrelated processes are so tightly linked in the Paramyxovirinae has been an enigma. This paper will review what is presently known about these two processes that are unique to viruses of this subfamily, and will discuss whether this enigmatic linkage could be due to the phenomenon of RNA virus error catastrophe.
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Affiliation(s)
- Daniel Kolakofsky
- Department of Microbiology and Molecular Medicine, Université de Genève, Geneva, Switzerland
| | - Laurent Roux
- Department of Microbiology and Molecular Medicine, Université de Genève, Geneva, Switzerland
| | - Dominique Garcin
- Department of Microbiology and Molecular Medicine, Université de Genève, Geneva, Switzerland
| | - Rob W H Ruigrok
- Laboratoire de Virologie Moléculaire et Structurale, FRE 2854 CNRS-Université Joseph Fourier, Grenoble, France
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34
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Bailey D, Banyard A, Dash P, Ozkul A, Barrett T. Full genome sequence of peste des petits ruminants virus, a member of the Morbillivirus genus. Virus Res 2005; 110:119-24. [PMID: 15845262 DOI: 10.1016/j.virusres.2005.01.013] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2004] [Revised: 01/25/2005] [Accepted: 01/25/2005] [Indexed: 11/17/2022]
Abstract
Peste des petits ruminants virus (PPRV) causes an acute febrile illness in small ruminant species, mostly sheep and goats. PPRV is a member of the Morbillivirus genus which includes measles, rinderpest (cattle plague), canine distemper, phocine distemper and the morbilliviruses found in whales, porpoises and dolphins. Full length genome sequences for these morbilliviruses are available and reverse genetic rescue systems have been developed for the viruses of terrestrial mammals, with the exception of PPRV. This paper presents the first published full length genome sequence for PPRV. The genome was found to be consistent with the rule-of-six and open reading frames (ORFs) were identified that encoded the eight proteins characteristic of morbilliviruses. At the nucleotide (nt) level, the full length genome of PPRV was most similar to that of rinderpest, the other ruminant morbillivirus. However, at the protein level five of the six structural proteins and the V protein showed a greater similarity to the dolphin morbillivirus (DMV) while only the C and L proteins showed a high relationship to rinderpest.
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Affiliation(s)
- Dalan Bailey
- Pirbright Laboratory, Institute for Animal Health, Ash Road, Woking, Surrey GU24 ONF, UK
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35
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Banyard AC, Baron MD, Barrett T. A role for virus promoters in determining the pathogenesis of Rinderpest virus in cattle. J Gen Virol 2005; 86:1083-1092. [PMID: 15784902 DOI: 10.1099/vir.0.80752-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Rinderpest virus (RPV) is a morbillivirus that causes cattle plague, a disease of large ruminants. The viral genome is flanked at the 3′ and 5′ genome termini by the genome promoter (GP) and antigenome promoter (AGP), respectively. These promoters play essential roles in directing replication and transcription as well as RNA encapsidation and packaging. It has previously been shown that individual changes to the GP of RPV greatly affect promoter activity in a minigenome assay and it was therefore proposed that individual nucleotide changes in the GP and AGP might also have significant effects on the ability of the virus to replicate and cause disease in cattle. The Plowright vaccine strain of RPV has been derived by tissue-culture passage from the virulent Kabete ‘O’ isolate (KO) and is highly attenuated for all ruminant species in which it has been used. Here, it was shown that swapping the GP and the first 76 nt of the AGP between virulent and avirulent strains affected disease progression. In particular, it was shown that flanking the virulent strain with the vaccine GP and AGP sequences, while not appreciably affecting virus growth in vitro, led to attenuation in vivo. The reverse was not true, since the KO promoters did not alter the vaccine's attenuated nature. The GP/AGP therefore play a role in attenuation, but are not the only determinants of attenuation in this vaccine.
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Affiliation(s)
| | | | - Thomas Barrett
- Institute for Animal Health, Pirbright, Surrey GU24 0NF, UK
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36
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Marcos F, Ferreira L, Cros J, Park MS, Nakaya T, García-Sastre A, Villar E. Mapping of the RNA promoter of Newcastle disease virus. Virology 2005; 331:396-406. [PMID: 15629782 DOI: 10.1016/j.virol.2004.10.040] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2004] [Revised: 08/25/2004] [Accepted: 10/25/2004] [Indexed: 11/18/2022]
Abstract
The RNA promoters of the genome and antigenome of Newcastle disease virus (NDV) were studied by mutational analysis of their 3' terminal ends. Similarly to other paramyxoviruses, NDV RNA replication follows the rule of six, and the genomic and antigenomic promoters require two discontinuous regions: conserved region I (first 18 nucleotides) and conserved region II (nucleotides 73-90). Proper spacing between those regions and the phase of six in region II is critical for efficient RNA promoter activity. As expected, the gene start signal at the 3' end of the NDV genome was required for mRNA transcription, but not for RNA replication. Surprisingly, mutation of the polyadenylation signal in the 5' end did not affect gene expression transcription. Although the conserved region I of NDV (avulavirus) promoter appears to be more similar to that of Sendai virus (SeV) (respirovirus), conserved region II is analogous to that of rubulaviruses.
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Affiliation(s)
- Fernando Marcos
- Departamento de Bioquímica y Biología Molecular, Universidad de Salamanca, Plaza Doctores de la Reina s/n, Edificio Departamental, lab. 108. Salamanca 37007, Spain
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37
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Vulliémoz D, Cordey S, Mottet-Osman G, Roux L. Nature of a paramyxovirus replication promoter influences a nearby transcription signal. J Gen Virol 2005; 86:171-180. [PMID: 15604444 DOI: 10.1099/vir.0.80435-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The genomic and antigenomic 3' ends of the Sendai virus replication promoters are bi-partite in nature. They are symmetrically composed of leader or trailer sequences, a gene start (gs) or gene end (ge) site, respectively, and a simple hexameric repeat. Studies of how mRNA synthesis initiates from the first gene start site (gs1) have been hampered by the fact that gs1 is located between two essential elements of the replication promoter. Transcription initiation, then, is separated from the replication initiation site by only 56 nt on the genome, so that transcription and replication may sterically interfere with each other. In order to study the initiation of Sendai virus mRNAs without this possible interference, Sendai virus mini-genomes were prepared having tandem promoters in which replication takes place from the external one, whereas mRNA synthesis occurs from the internal one. Transcription now initiates at position 146 rather than position 56 relative to the genome 3' end. Under these conditions, it was found that the frequency with which mRNA synthesis initiates depends, in an inverse fashion, on the strength of the external replication promoter. It was also found that the sequences essential for replication are not required for basic mRNA synthesis as long as there is an external replication promoter at which viral RNA polymerase can enter the nucleocapsid template. The manner in which transcription and replication initiations influence each other is discussed.
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Affiliation(s)
- Diane Vulliémoz
- Department of Microbiology and Molecular Medicine, University of Geneva Medical School, CMU, 1 rue Michel-Servet, CH-1211 Geneva 4, Switzerland
| | - Samuel Cordey
- Department of Microbiology and Molecular Medicine, University of Geneva Medical School, CMU, 1 rue Michel-Servet, CH-1211 Geneva 4, Switzerland
| | - Geneviève Mottet-Osman
- 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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38
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McGivern DR, Collins PL, Fearns R. Identification of internal sequences in the 3' leader region of human respiratory syncytial virus that enhance transcription and confer replication processivity. J Virol 2005; 79:2449-60. [PMID: 15681446 PMCID: PMC546581 DOI: 10.1128/jvi.79.4.2449-2460.2005] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2004] [Accepted: 09/23/2004] [Indexed: 11/20/2022] Open
Abstract
Previous studies of respiratory syncytial virus have shown that the 44-nucleotide (nt) leader (Le) region is sufficient to initiate RNA replication, producing antigenome RNA, and that the Le and adjoining gene start (GS) signal of the first gene are sufficient to initiate transcription, producing mRNA. A cis-acting element necessary for both transcription and replication was mapped within the first 11 nt at the 3' end of Le. In the present study the remainder of the Le region was mapped to identify sequences important for transcription and replication. A series of minigenomes with mutant Le sequences was generated, and their ability to direct transcription and replication was determined by Northern blot analysis, which examined full-length antigenome and mRNA, and by primer extension analysis, which examined antigenome and mRNA initiation. With regard to transcription, nt 36 to 43, located immediately upstream of the GS signal, were found to be necessary for optimal levels of mRNA synthesis, although the GS signal in conjunction with the 3'-terminal region of Le was sufficient to direct accurate mRNA synthesis initiation. With regard to replication, the first 15 nt of Le were found to be sufficient to direct initiation of antigenome synthesis, but nt 16 to 34 were required in addition for efficient encapsidation and production of full-length antigenome. Analysis of transcripts produced from di- and tricistronic minigenomes indicated that a significant proportion of abortive replicases continue RNA synthesis to the end of the first gene and then continue in a transcription mode along the remainder of the genome.
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Affiliation(s)
- David R McGivern
- Division of Pathology and Neuroscience, University of Dundee Medical School, Ninewells Hospital, Dundee DD1 9SY, UK
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39
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Malur AG, Hoffman MA, Banerjee AK. The human parainfluenza virus type 3 (HPIV 3) C protein inhibits viral transcription. Virus Res 2004; 99:199-204. [PMID: 14749186 DOI: 10.1016/j.virusres.2003.11.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The C protein of human parainfluenza virus type 3 (HPIV 3), like other paramyxovirus C proteins, is synthesized from an alternate open reading frame (ORF) encoded within the phosphoprotein (P) mRNA, in addition, to two other proteins, namely D and V, which arise from the same mRNA by a process of transcriptional editing. The precise role of the C, D, and V proteins in viral transcription and replication, and their interaction, if any, with other viral proteins remains unknown. To ascertain the role of the C protein, we have examined its effect on transcription using an HPIV 3 minigenome construct and monitoring the luciferase reporter gene expression. Our results demonstrate that the HPIV 3 C protein effectively inhibits minigenome transcription in a dose-dependent manner. Interestingly, the Sendai virus (Se-V) C protein was also capable of inducing an inhibitory effect on the HPIV 3 minigenome transcription, thus demonstrating a heterologous interaction. A coiled-coil motif within the C protein has been identified, and a deletion mutant within this motif abrogated the inhibitory effect significantly thereby implying that oligomerization of the C protein may be involved in inhibition of transcription.
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Affiliation(s)
- Achut G Malur
- Department of Virology NN-10, The Lerner Research Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA
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40
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Le Mercier P, Garcin D, Garcia E, Kolakofsky D. Competition between the Sendai virus N mRNA start site and the genome 3'-end promoter for viral RNA polymerase. J Virol 2003; 77:9147-55. [PMID: 12915531 PMCID: PMC187394 DOI: 10.1128/jvi.77.17.9147-9155.2003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The genomic and antigenomic 3'-end replication promoters of Sendai virus are bipartite in nature and symmetrical, composed of le or tr sequences; a gene start or gene end site, respectively; and a simple hexameric repeat. The relative strengths of these 3'-end promoters determines the ratios of genomes and antigenomes formed during infection and whether model mini-genomes can be rescued from DNA by nondefective helper viruses. Using these tests of promoter strength, we have confirmed that tr is stronger than le in this respect. We have also found that the presence of a gene start site within either 3'-end promoter strongly reduces 3'-end promoter strength. The negative effects of the gene start site on the 3'-end promoter suggest that these closely spaced RNA start sites compete with each other for a common pool of viral RNA polymerase. The manner in which this competition could occur for polymerase off the template (in trans) and polymerase on the template (in cis) adds insight into how the viral RNA polymerase switches between its dual functions as transcriptase and replicase.
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Affiliation(s)
- Philippe Le Mercier
- Department of Genetics and Microbiology, University of Geneva School of Medicine, CH1211 Geneva, Switzerland
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41
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Keller MA, Parks GD. Positive- and negative-acting signals combine to determine differential RNA replication from the paramyxovirus simian virus 5 genomic and antigenomic promoters. Virology 2003; 306:347-58. [PMID: 12642107 DOI: 10.1016/s0042-6822(02)00071-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The cis-acting signals found at the 3' ends of the genomic and antigenomic RNAs are a major factor determining the level of paramyxovirus RNA replication from each promoter. Using a minigenome system that reconstitutes SV5 RNA synthesis from cDNA-derived components, we show here that the genomic promoter (GP) for the paramyxovirus SV5 directs RNA replication approximately 14-fold lower than that seen from the antigenomic promoter (AGP). The goal of this study was to identify cis-acting signals responsible for differential levels of RNA replication from the SV5 GP and AGP. We have previously shown that the SV5 AGP contains three sequence-dependent elements (CRI, CRII, and Region III) that are separated by sequence-independent spacer regions. Minigenomes containing chimeric promoters were constructed to test the hypothesis that transfer of discrete cis-acting AGP elements to the GP could confer higher replication properties to the GP. Minigenomes containing a substitution of the AGP CRI, CRII, or Region III elements alone in place of the corresponding GP sequences did not show enhanced levels of RNA replication. However, transfer of both the AGP 3' terminal CRI and Region III elements into the corresponding sites of the GP led to a minigenome which replicated to approximately 40% of the levels seen with the AGP. This enhanced RNA replication from the GP was further increased up to AGP levels by also including the intervening AGP segment (bases 20-50) located between CRI and Region III. Importantly, transfer of nonviral sequences in place of GP bases 20-50 also increased RNA replication to levels approaching that of the AGP, but only in the context of the AGP CRI and Region III substitutions. These data indicate that differential levels of RNA replication from the SV5 GP and AGP are due to a combination of positive-acting signals in the AGP (CRI and Region III) and a negative-acting signal in the GP (bases 20-50). Possible functions for the SV5 promoter elements in determining RNA replication levels are proposed.
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Affiliation(s)
- Michael A Keller
- Department of Microbiology and Immunology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157-1064, USA
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42
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Gupta AK, Shaji D, Banerjee AK. Identification of a novel tripartite complex involved in replication of vesicular stomatitis virus genome RNA. J Virol 2003; 77:732-8. [PMID: 12477878 PMCID: PMC140603 DOI: 10.1128/jvi.77.1.732-738.2003] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Our laboratory's recent observations that transcriptionally inactive phosphoprotein (P) mutants can efficiently function in replicating vesicular stomatitis virus (VSV) defective interfering particle in a three-plasmid-based (L, P, and N) reverse genetics system in vivo (A. K. Pattnaik, L. Hwang, T. Li, N. Englund, M. Mathur, T. Das, and A. K. Banerjee, J. Virol. 71:8167-8175, 1997) led us to propose that a tripartite complex consisting of L-(N-P) protein may represent the putative replicase for synthesis of the full-length genome RNA. In this communication we demonstrate that such a complex is indeed detectable in VSV-infected BHK cells. Furthermore, coexpression of L, N, and P proteins in Sf21 insect cells by recombinant baculovirus containing the respective genes also resulted in the formation of a tripartite complex, as shown by immunoprecipitation with specific antibodies. A basic amino acid mutant of P protein, P260A, previously shown to be inactive in transcription but active in replication (T. Das, A. K. Pattnaik, A. M. Takacs, T. Li, L. N. Hwang, and A. K. Banerjee, Virology 238:103-114, 1997) was also capable of forming the mutant [L-(N-Pmut)] complex in both insect cells and BHK cells. Sf21 extract containing either the wild-type P protein or the mutant P protein along with the L and N proteins was capable of synthesizing 42S genome-sense RNA in an in vitro replication reconstitution reaction. Addition of N-Pmut or wild-type N-P complex further stimulated the synthesis of the genome-length RNA. These results indicate that the transcriptase and replicase complexes of VSV are possibly two distinct entities involved in carrying out capped mRNAs and uncapped genome and antigenome RNAs, respectively.
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Affiliation(s)
- Ashim K Gupta
- Department of Virology, Lerner Research Institute, The Cleveland Clinic Foundation, Ohio 44195, USA
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43
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Neumann G, Whitt MA, Kawaoka Y. A decade after the generation of a negative-sense RNA virus from cloned cDNA - what have we learned? J Gen Virol 2002; 83:2635-2662. [PMID: 12388800 DOI: 10.1099/0022-1317-83-11-2635] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Since the first generation of a negative-sense RNA virus entirely from cloned cDNA in 1994, similar reverse genetics systems have been established for members of most genera of the Rhabdo- and Paramyxoviridae families, as well as for Ebola virus (Filoviridae). The generation of segmented negative-sense RNA viruses was technically more challenging and has lagged behind the recovery of nonsegmented viruses, primarily because of the difficulty of providing more than one genomic RNA segment. A member of the Bunyaviridae family (whose genome is composed of three RNA segments) was first generated from cloned cDNA in 1996, followed in 1999 by the production of influenza virus, which contains eight RNA segments. Thus, reverse genetics, or the de novo synthesis of negative-sense RNA viruses from cloned cDNA, has become a reliable laboratory method that can be used to study this large group of medically and economically important viruses. It provides a powerful tool for dissecting the virus life cycle, virus assembly, the role of viral proteins in pathogenicity and the interplay of viral proteins with components of the host cell immune response. Finally, reverse genetics has opened the way to develop live attenuated virus vaccines and vaccine vectors.
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Affiliation(s)
- Gabriele Neumann
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, 2015 Linden Drive West, Madison, WI 53706, USA1
| | - Michael A Whitt
- Department of Molecular Sciences, University of Tennessee Health Science Center, Memphis, TN, USA2
| | - Yoshihiro Kawaoka
- CREST, Japan Science and Technology Corporation, Japan4
- Institute of Medical Science, University of Tokyo, Tokyo, Japan3
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, 2015 Linden Drive West, Madison, WI 53706, USA1
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44
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Choudhary SK, Malur AG, Huo Y, De BP, Banerjee AK. Characterization of the oligomerization domain of the phosphoprotein of human parainfluenza virus type 3. Virology 2002; 302:373-82. [PMID: 12441081 DOI: 10.1006/viro.2002.1668] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The phosphoprotein (P) of human parainfluenza virus type 3 (HPIV 3) plays a central role in the viral genome RNA transcription and replication. It acts as an essential cofactor of the RNA polymerase (L) by forming a functional L-P complex, binds to the genomic N-RNA template to recruit the L-P complex for RNA synthesis, and interacts with the nucleocapsid protein (N) to form the encapsidation complex (N-P). We have earlier demonstrated that the P protein forms oligomers (B. P. De, M. A. Hoffman, S. Choudhary, C. C. Huntley, and A. K. Banerjee, 2000, J. Virol. 74, 5886-5895) and in this article we identified the putative oligomerization domain of the P protein and studied the role of this domain in transcription. By computer analyses, we have localized a high-score coiled-coil motif characteristic of oligomerization domain residing between the amino acid residues 423 and 457 of the P protein. Deletion of 12 amino acid residues within this coiled-coil motif (P Delta 439-450) completely abrogated oligomerization, whereas deletion in other regions outside the motif had no significant effect. The mutant P Delta 439-450 was both defective in mRNA synthesis in vitro and minigenome transcription in vivo. Interestingly, the mutant interacted with L to form L-P complex, albeit less efficiently, while its interaction with N protein to form N-P complex and with N-RNA template was similar to the wt P protein. Our results indicate that oligomerization provides a key function to the P protein in the transcription of HPIV 3 genome RNA.
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Affiliation(s)
- Suresh K Choudhary
- Department of Virology NN-10, Lerner Research Institute, The Cleveland Clinic Foundation, Ohio 44195, USA
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45
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Fujii Y, Sakaguchi T, Kiyotani K, Huang C, Fukuhara N, Egi Y, Yoshida T. Involvement of the leader sequence in Sendai virus pathogenesis revealed by recovery of a pathogenic field isolate from cDNA. J Virol 2002; 76:8540-7. [PMID: 12163573 PMCID: PMC136997 DOI: 10.1128/jvi.76.17.8540-8547.2002] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We previously demonstrated that a systematic passage of a pathogenic field isolate of Sendai virus (SeV), the Hamamatsu strain, in embryonated eggs caused attenuation of virulence to mice, and we isolated viral clones of distinct virulence (K. Kiyotani et al. Arch. Virol. 146:893-908, 2001). One of the clones, E15cl2, which was obtained from the virus at the 15th egg passage of E0, the parental Hamamatsu clone for egg passage, had 165-fold-attenuated virulence to mice and possessed only four mutations in the entire 15,384-base genome: in an antigenomic sense, U to A at position 20 (U20A) and U to A at position 24 (U24A) in the leader sequence, the promoter for transcription and replication, and A to G at position 9346 (silent) and A to U at position 12174 (Ser to Cys) in the L gene. To examine the possibility that leader mutations affect virus pathogenesis, we recovered live viruses from cDNA derived from the Hamamatsu strain. A mutant virus possessing either a mutation of U20A or U24A in the leader sequence showed a slightly lower pathogenicity than that of the parental virus, whereas a double mutant virus possessing both of the mutations showed 25-fold-attenuated virulence, accompanying a significantly lower virus replication in the mouse lung. Replications of the leader mutant viruses were also impaired in a primary culture of mouse pulmonary epithelial cells but not in chicken embryo fibroblasts. These findings suggest that leader mutations of SeV affect virus pathogenesis by altering virus replication in a host-dependent manner.
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Affiliation(s)
- Yutaka Fujii
- Department of Virology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 734-8551, Japan
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Malur AG, Choudhary SK, De BP, Banerjee AK. Role of a highly conserved NH(2)-terminal domain of the human parainfluenza virus type 3 RNA polymerase. J Virol 2002; 76:8101-9. [PMID: 12134015 PMCID: PMC155155 DOI: 10.1128/jvi.76.16.8101-8109.2002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The RNA polymerase complex of human parainfluenza virus type 3 (HPIV 3), a member of the family Paramyxoviridae, is composed of two virally encoded polypeptides: a multifunctional large protein (L, 255 kDa) and a phosphoprotein (P, 90 kDa). From extensive deduced amino acid sequence analyses of the cDNA clones of a number of L proteins of nonsegmented negative-strand RNA viruses, a cluster of high-homology sequence segments have been identified within the body of the L proteins. Here, we have focused on the NH(2)-terminal domain of HPIV 3 L protein that is also highly conserved. Following mutational analyses within this domain, we examined the ability of the mutant L proteins to (i) transcribe an HPIV 3 minireplicon, (ii) transcribe the viral RNA in vitro using the HPIV 3 nucleocapsid RNA template, and (iii) interact with HPIV 3 P protein. Our results demonstrate that the first 15 amino acids of the NH(2)-terminal domain spanning a highly conserved motif is directly involved in transcription of the genome RNA and in forming a functional complex with the P protein. Substitution of eight nonconserved amino acids within this domain by the corresponding Sendai virus L protein residues yielded mutants with variable transcriptional activities. However, one mutant in which all eight amino acids were replaced with the corresponding residues of Sendai virus L protein failed to both transcribe the minireplicon and interact with HPIV 3 P and the Sendai virus P protein. The possible functional significance of the NH(2)-terminal domain of paramyxovirus L protein is discussed.
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Affiliation(s)
- Achut G Malur
- Department of Virology, Lerner Research Institute, Cleveland Clinic Foundation, Ohio 44195, USA
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Le Mercier P, Garcin D, Hausmann S, Kolakofsky D. Ambisense sendai viruses are inherently unstable but are useful to study viral RNA synthesis. J Virol 2002; 76:5492-502. [PMID: 11991977 PMCID: PMC137047 DOI: 10.1128/jvi.76.11.5492-5502.2002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Ambisense Sendai virus (SeV) was prepared in order to study the control of viral RNA synthesis. In these studies, we found that the relative ratios of genomes/antigenomes formed during infection are largely determined by the relative strengths of the replication promoters, independent of the presence of a functional mRNA start site. We also found that the ability of the viral polymerase (vRdRP) to respond to an mRNA editing site requires prior (re)initiation at an mRNA start site, similar to the acquisition of vRdRP processivity in the absence of nascent chain coassembly. During these studies, the inherent instability of ambisense SeV upon passage in embryonated chicken eggs was noted and was found to be associated with a point mutation in the ambisense mRNA (ambi-mRNA) start site that severely limited its expression. Since the interferon (IFN)-induced antiviral state is mediated in part via double-stranded RNA (dsRNA), the efficiency of the ambi-mRNA poly(A)/stop site was examined. This site was found to operate in a manner similar to that of other SeV mRNA poly(A)/stop sites, i.e., at approximately 95% efficiency. This modest level of vRdRP read-through is apparently tolerable for natural SeV because the potential to form dsRNA during infection remains limited. However, when mRNAs are expressed from ambisense SeV antigenomes, vRdRP read-through of the ambi-mRNA poly(A)/stop site creates a capped transcript that can potentially extend the entire length of the antigenome, since there are no further poly(A)/stop sites here. In support of this hypothesis, loss of ambi-mRNA expression during passage of ambisense SeV stocks in eggs is also characterized by conversion of virus that grows poorly in IFN-sensitive cultures and is relatively IFN sensitive to virus that grows well even in IFN-pretreated cells that restrict vesicular stomatitis virus replication, i.e., the wild-type SeV phenotype. The selection of mutants unable to express ambi-mRNA on passage in chicken eggs is presumably due to increased levels of dsRNA during infection. How natural ambisense viruses may deal with this dilemma is discussed.
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Affiliation(s)
- Philippe Le Mercier
- Department of Genetics and Microbiology, University of Geneva School of Medicine, CH1211 Geneva, Switzerland
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Fearns R, Peeples ME, Collins PL. Mapping the transcription and replication promoters of respiratory syncytial virus. J Virol 2002; 76:1663-72. [PMID: 11799161 PMCID: PMC135899 DOI: 10.1128/jvi.76.4.1663-1672.2002] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
An important, unresolved issue in mononegavirus biology is whether or not transcription is initiated by the same promoter as RNA replication. In this study, residues important for respiratory syncytial virus (RSV) transcription and RNA replication were identified by subjecting the first 26 nucleotides of genome RNA to saturation mutagenesis. This analysis was performed using a genome analog that allowed transcription and RNA replication to be dissociated from each other and monitored as independent events in an intracellular assay. This analysis showed that nucleotides 3C, 5C, 8U, 9U, 10U, and 11U were important for transcription and RNA replication. Additional nucleotides (1U, 2G, 6U, and 7U) were important for RNA replication, but not transcription. At position 4, G versus C or U augmented transcription and decreased replication, showing that the naturally occurring assignments in the genomic (4G) and antigenomic (4U) promoters are optimal for transcription and RNA replication, respectively. These data show that RSV transcription and RNA replication each involve a cis-acting signal at the very 3" end of the genome. This signal appears to contain a minimum, common element that functions in both transcription and RNA replication, defined by those substitutions that had similar effects on the two processes. Apart from these common nucleotides, other positions were involved in RNA replication but not transcription or had different effects on the two processes. This indicates that the promoters for transcription and replication involve overlapping sets of nucleotides at the very 3" end of the genome and provides evidence that the nucleotide preferences for the two processes are not identical.
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Affiliation(s)
- Rachel Fearns
- Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892-0720, USA
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Mioulet V, Barrett T, Baron MD. Scanning mutagenesis identifies critical residues in the rinderpest virus genome promoter. J Gen Virol 2001; 82:2905-2911. [PMID: 11714965 DOI: 10.1099/0022-1317-82-12-2905] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Short regions at the 3' and 5' ends of the genome of Rinderpest virus (RPV) contain signals that regulate transcription of the viral genome, known as the genome promoter and the (complement to the) antigenome promoter, respectively. An RPV minigenome construct carrying the CAT coding sequence was used as a reporter to investigate residues in the 3'-terminal region of the genome important for these functions. Single-base scanning mutagenesis showed that modifications to nucleotides 1, 3, 4, 10 and 19 of the RPV leader had an extremely inhibitory effect on transcription and/or encapsidation of the minigenome, with CAT expression reduced to 0-10% of control values. Changes in any of the other first 22 nucleotides reduced the efficiency of the minigenome to 20-80% of the wild-type control, with the exception of nucleotides 16, 17 and 20, where mutations did not affect CAT expression significantly. Mutagenesis in blocks identified critical residues in positions 23-26, but changes to leader residues 27-48 had no major effect on CAT expression. A region of about 16 nucleotides (49-65) located around the start of the nucleocapsid gene, including the intergenic triplet CTT, was identified as essential for minigenome function. Mutations further into the nucleocapsid gene (nt 66-89) had a moderate effect (CAT activity 20-60% of control), while at least one critical residue was found in positions 93-96. The importance of four highly conserved G residues at positions 79, 85, 91 and 97 was also investigated. G79 was found to be optimal, though not critical, while a purine was required at 85 and 91. Although G97 is conserved in morbilliviruses, all bases were equally effective at this position.
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Affiliation(s)
- Valerie Mioulet
- Division of Molecular Biology, Institute for Animal Health, Pirbright Laboratory, Ash Road, Pirbright, GU24 0NF, UK1
| | - Thomas Barrett
- Division of Molecular Biology, Institute for Animal Health, Pirbright Laboratory, Ash Road, Pirbright, GU24 0NF, UK1
| | - Michael D Baron
- Division of Molecular Biology, Institute for Animal Health, Pirbright Laboratory, Ash Road, Pirbright, GU24 0NF, UK1
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Haller AA, Miller T, Mitiku M, Coelingh K. Expression of the surface glycoproteins of human parainfluenza virus type 3 by bovine parainfluenza virus type 3, a novel attenuated virus vaccine vector. J Virol 2000; 74:11626-35. [PMID: 11090161 PMCID: PMC112444 DOI: 10.1128/jvi.74.24.11626-11635.2000] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bovine parainfluenza virus type 3 (bPIV3) is being evaluated as an intranasal vaccine for protection against human PIV3 (hPIV3). In young infants, the bPIV3 vaccine appears to be infectious, attenuated, immunogenic, and genetically stable, which are desirable characteristics for an RNA virus vector. To test the potential of the bPIV3 vaccine strain as a vector, an infectious DNA clone of bPIV3 was assembled and recombinant bPIV3 (r-bPIV3) was rescued. r-bPIV3 displayed a temperature-sensitive phenotype for growth in tissue culture at 39 degrees C and was attenuated in the lungs of Syrian golden hamsters. In order to test whether r-bPIV3 could serve as a vector, the fusion and hemagglutinin-neuraminidase genes of bPIV3 were replaced with those of hPIV3. The resulting bovine/human PIV3 was temperature sensitive for growth in Vero cells at 37 degrees C. The replication of bovine/human PIV3 was also restricted in the lungs of hamsters, albeit not as severely as was observed for r-bPIV3. Despite the attenuation phenotypes observed for r-bPIV3 and bovine/human PIV3, both of these viruses protected hamsters completely upon challenge with hPIV3. In summary, bPIV3 was shown to function as a virus vector that may be especially suitable for vaccination of infants and children against PIV3 and other viruses.
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Affiliation(s)
- A A Haller
- Aviron, Mountain View, California 94043, USA.
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