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Bowden TR, Westenberg M, Wang LF, Eaton BT, Boyle DB. Molecular characterization of Menangle virus, a novel paramyxovirus which infects pigs, fruit bats, and humans. Virology 2001; 283:358-73. [PMID: 11336561 DOI: 10.1006/viro.2001.0893] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Menangle virus (MenV), isolated in August 1997 following an outbreak of reproductive disease in a piggery in New South Wales, is the second previously unclassified member of the family Paramyxoviridae to be identified in Australia since 1994. Similar to Hendra virus (HeV), MenV appears to be a virus of fruit bats (flying foxes) in the genus Pteropus. No serological cross-reactivity was detected between MenV and other known paramyxoviruses and to facilitate virus classification a cDNA subtraction method was used to obtain viral-specific cDNA from MenV-infected cells. Cloning and sequencing of the products enabled the entire sequences of the NP, P/V, M, F, and HN genes to be determined. Comparison of the nucleotide and deduced amino acid sequences for each gene with members of the family Paramyxoviridae, determination of the P gene mRNA editing strategy, and phylogenetic analyses confirmed that MenV is a new member of the genus Rubulavirus. However the deduced protein sequence of MenV HN exhibited only limited sequence homology when compared with attachment proteins of other paramyxoviruses. Key differences within the amino acid residues considered important determinants of neuraminidase activity suggest MenV HN is unlikely to possess the same degree of neuraminidase activity characteristic of other rubulavirus and respirovirus HN proteins.
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Affiliation(s)
- T R Bowden
- CSIRO Livestock Industries, Australian Animal Health Laboratory, Geelong, Victoria 3220, Australia.
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Sweetman DA, Miskin J, Baron MD. Rinderpest virus C and V proteins interact with the major (L) component of the viral polymerase. Virology 2001; 281:193-204. [PMID: 11277692 DOI: 10.1006/viro.2000.0805] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Rinderpest virus, like other Morbilliviruses, expresses three proteins from the single P gene. In addition to the P protein, which interacts both with the viral polymerase (L) and the nucleocapsid (N) protein, the virus expresses a C and a V protein from the same gene. The functions of these two proteins in the viral life cycle are not clear. Although both C and V proteins are dispensable, in that viable viruses can be made that express neither, each seems to play a role in optimum viral replication. We have used the yeast-two hybrid system, binding to coexpressed fusions of C and V to glutathione-S-transferase, and studies of the native size of these proteins to investigate interactions of the rinderpest virus C and V proteins with other virus-encoded proteins. The V protein was found to interact with both the N and L proteins, while the C protein was found to bind to the L protein, and to self-associate in high-molecular-weight aggregates.
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Affiliation(s)
- D A Sweetman
- Institute for Animal Health, Ash Road, Surrey, Pirbright, GU24 0NF, United Kingdom
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Baron MD, Barrett T. Rinderpest viruses lacking the C and V proteins show specific defects in growth and transcription of viral RNAs. J Virol 2000; 74:2603-11. [PMID: 10684274 PMCID: PMC111748 DOI: 10.1128/jvi.74.6.2603-2611.2000] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/1999] [Accepted: 12/21/1999] [Indexed: 11/20/2022] Open
Abstract
Rinderpest virus is a morbillivirus and the causative agent of an important disease of cattle and wild bovids. The P genes of all morbilliviruses give rise to two proteins in addition to the P protein itself: use of an alternate start translation site, in a second open reading frame, gives rise to the C protein, while cotranscriptional insertion of an extra base gives rise to the V protein, a fusion of the amino-terminal half of P to a short, highly conserved, cysteine-rich zinc binding domain. Little is known about the function of either of these two proteins in the rinderpest virus life cycle. We have constructed recombinant rinderpest viruses in which the expression of these proteins has been suppressed, individually and together, and studied the replication of these viruses in tissue culture. We show that the absence of the V protein has little effect on the replication rate of the virus but does lead to an increase in synthesis of genome and antigenome RNAs and a change in cytopathic effect to a more syncytium-forming phenotype. Virus that does not express the C protein, on the other hand, is clearly defective in growth in all cell lines tested, and this defect appears to be related to a decreased transcription of mRNA from viral genes. The phenotypes of both individual mutant virus types are both expressed in the double mutant expressing neither V nor C.
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Affiliation(s)
- M D Baron
- Institute for Animal Health, Pirbright, Surrey GU24 ONF, United Kingdom.
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Tober C, Seufert M, Schneider H, Billeter MA, Johnston IC, Niewiesk S, ter Meulen V, Schneider-Schaulies S. Expression of measles virus V protein is associated with pathogenicity and control of viral RNA synthesis. J Virol 1998; 72:8124-32. [PMID: 9733853 PMCID: PMC110150 DOI: 10.1128/jvi.72.10.8124-8132.1998] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/1998] [Accepted: 07/08/1998] [Indexed: 11/20/2022] Open
Abstract
Nonstructural proteins encoded by measles virus (MV) include the V protein which is translated from an edited P mRNA. V protein is not associated with intracellular or released viral particles and has recently been found to be dispensable for MV propagation in cell culture (H. Schneider, K. Kaelin, and M. A. Billeter, Virology 227:314-322, 1997). Using recombinant MVs (strain Edmonston [ED]) genetically engineered to overexpress V protein (ED-V+) or to be deficient for V protein (ED-V-), we found that in the absence of V both MV-specific proteins and RNAs accumulated to levels higher than those in the parental MV molecular clone (ED-tag), whereas MV-specific gene expression was strongly attenuated in human U-87 glioblastomas cells after infection with ED-V+. The titers of virus released from these cells 48 h after infection with either V mutant virus were lower than those from cells infected with ED-tag. Similarly, significantly reduced titers of infectious virus were reisolated from lung tissue of cotton rats (Sigmodon hispidus) after intranasal infection with both editing mutants compared to titers isolated from ED-tag-infected animals. In cell culture, expression of V protein led to a redistribution of MV N protein in doubly transfected Cos-7 cells, indicating that these proteins form heterologous complexes. This interaction was further confirmed by using a two-hybrid approach with both proteins expressed as Gal4 or VP16 fusion products. Moreover, V protein efficiently competed complexes formed between MV N and P proteins. These findings indicate that V protein acts to balance accumulation of viral gene products in cell culture, and this may be dependent on its interaction with MV N protein. Furthermore, expression of V protein may contribute to viral pathogenicity in vivo.
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Affiliation(s)
- C Tober
- Institute for Virology and Immunobiology, University of Würzburg, D-97078 Würzburg, Germany
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Delenda C, Hausmann S, Garcin D, Kolakofsky D. Normal cellular replication of Sendai virus without the trans-frame, nonstructural V protein. Virology 1997; 228:55-62. [PMID: 9024809 DOI: 10.1006/viro.1996.8354] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The Sendai virus V protein is a nonstructural trans-frame protein in which a highly conserved cys-rich Zn2+-binding domain is fused to the N-terminal half of the P protein via mRNA editing. Using a recently developed system in which infectious virus is recovered from cDNA, we have engineered a virus in which a translation stop codon was placed at the beginning of the V ORF. Translation of the V(stop) mRNA yields a W-like protein, i.e., a protein composed of the N-terminal half of the P protein alone which is naturally expressed at low levels from the P gene. This V-minus but W-augmented virus was found to replicate normally in cell culture and embryonated chicken eggs. The Sendai virus V protein is thus an accessory protein, and the cys-rich Zn2+-binding domain is likely to function in a specialized role during virus propagation.
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Affiliation(s)
- C Delenda
- Department of Genetics and Microbiology, University of Geneva School of Medicine, Switzerland
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Liston P, Briedis DJ. Ribosomal frameshifting during translation of measles virus P protein mRNA is capable of directing synthesis of a unique protein. J Virol 1995; 69:6742-50. [PMID: 7474085 PMCID: PMC189585 DOI: 10.1128/jvi.69.11.6742-6750.1995] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Members of the Paramyxoviridae family utilize a variety of different strategies to increase coding capacity within their P cistrons. Translation initiation at alternative 5'-proximal AUG codons is used by measles virus (MV) to express the virus-specific P and C proteins from overlapping reading frames on their mRNAs. Additional species of mRNAs are transcribed from the MV P cistron by the insertion of extra nontemplated G residues at a specific site within the P transcript. Addition of only a single nontemplated G residue results in the expression of the V protein, which contains a unique carboxyl terminus. We have used an Escherichia coli system to express MV P cistron-related mRNAs and proteins. We have found that ribosomal frameshifting on the MV P protein mRNA is capable of generating a previously unrecognized P cistron-encoded protein that we have designated R. Some ribosomes which have initiated translation of the P protein mRNA use the sequence TCC CCG AG (24 nucleotides upstream of the V protein stop codon) to slip into the -1 reading frame, thus translating the sequence as TC CCC GAG. The resulting R protein terminates five codons downstream of the frameshift site at the V protein stop codon. We have gone on to use a chloramphenicol acetyltransferase reporter system to demonstrate that this MV-specific sequence is capable of directing frameshifting during in vivo translation in eukaryotic cells. Analysis of immunoprecipitated proteins from MV-infected cells by two-dimensional gel electrophoresis allowed detection of a protein species consistent with R protein in MV-infected cells. Quantitation of this protein species allowed a rough estimation of frameshift frequency of approximately 1.8%. Significant stimulation of ribosomal frameshift frequency at this locus of the MV P mRNA was mediated by a downstream stimulator element which, although not yet fully defined, appeared to be neither a conventional stem-loop nor an RNA pseudoknot structure.
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Affiliation(s)
- P Liston
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
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Liston P, DiFlumeri C, Briedis DJ. Protein interactions entered into by the measles virus P, V, and C proteins. Virus Res 1995; 38:241-59. [PMID: 8578862 DOI: 10.1016/0168-1702(95)00067-z] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Measles virus (MV) expresses at least 3 proteins from the phosphoprotein (P) cistron. Alternative translation initiation directs synthesis of the C protein from the +1 reading frame, while so-called RNA editing generates a second population of mRNAs which express the V protein from the -1 reading frame which lies within and overlaps the larger P reading frame. While the P protein has been demonstrated to be an essential cofactor for the L protein in the formation of active transcriptase complexes, the functions of the V and C proteins remain unknown. In order to investigate these functions, we have expressed the MV P, V and C proteins as GST fusions in E. coli for affinity purification and use in an in vitro binding assay with other viral and cellular proteins. The P protein was found to interact with L, NP, and with itself. These interactions were mapped to the carboxy-terminal half of the protein which is absent in the V protein. In contrast, both the V and C proteins failed to interact with any other viral proteins, but were each found to interact specifically with one or more cellular proteins. Appropriate aspects of these results were confirmed in vivo using the yeast two-hybrid system. These observations suggest that the V and C proteins may be involved in modulation of the host cellular environment within MV-infected cells. Such activity would be distinct from their previously proposed role in the possible down-regulation of virus-specific RNA transcription and replication.
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Affiliation(s)
- P Liston
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
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Gombart AF, Hirano A, Wong TC. Nucleoprotein phosphorylated on both serine and threonine is preferentially assembled into the nucleocapsids of measles virus. Virus Res 1995; 37:63-73. [PMID: 7483823 DOI: 10.1016/0168-1702(95)00020-q] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The nucleoprotein (N) in the nucleocapsids of measles virus (MV) has different conformation and antigenicity than the free N-protein in MV-infected cells. These two forms of N-protein have identical methionine-containing tryptic peptides. The free N-protein contains 4 phosphorylated tryptic peptides. However, the nucleocapsid-associated N-protein has an additional phosphorylated peptide not found in the free N-protein. The free N-protein is phosphorylated only on serine residues, whereas the nucleocapsid-associated N-protein is phosphorylated on both serine and threonine residues. The MV N-protein expressed from a cloned gene in primate cells is also phosphorylated on both serine and threonine residues. These results suggest that cellular kinases phosphorylate the MV N-protein, and N-protein with phosphorylated serine and threonine is preferentially assembled into the viral nucleocapsids.
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Affiliation(s)
- A F Gombart
- Department of Microbiology, University of Washington School of Medicine, Seattle 98195, USA
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Horikami SM, Moyer SA. Structure, transcription, and replication of measles virus. Curr Top Microbiol Immunol 1995; 191:35-50. [PMID: 7789161 DOI: 10.1007/978-3-642-78621-1_3] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- S M Horikami
- Department of Immunology and Medical Microbiology, College of Medicine, University of Florida, Gainesville 32610-0266, USA
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Schneider-Schaulies S, Schneider-Schaulies J, Dunster LM, ter Meulen V. Measles virus gene expression in neural cells. Curr Top Microbiol Immunol 1995; 191:101-16. [PMID: 7789154 DOI: 10.1007/978-3-642-78621-1_7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Abstract
We have obtained a polyclonal antiserum, N-BE, against the denatured, amino-terminal half of the measles virus (MV) nucleocapsid (N) protein and a monoclonal antibody (MAb), N46, which recognizes a conformation-dependent epitope in the same region. Amino acid residues 23 to 239 were required and sufficient for the formation of the conformational epitope. Using these antibodies, we show that the N protein of MV is synthesized as a relatively unfolded protein which first appears in the free-protein pool. This nascent N protein undergoes a conformational change into a more folded mature form. This change does not require the participation of other viral proteins or genomic RNA. The mature N protein does not accumulate in the free-protein pool but is quickly and selectively incorporated into the viral nucleocapsids. The mature N protein is a target for interaction with the phosphoprotein (P protein) of MV. This interaction interferes with the recognition of the N protein by the N46 MAb. This suggests that the association with the P protein may mask the binding site for the N46 MAb or that it induces a conformational change in the N protein.
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Affiliation(s)
- A F Gombart
- Department of Microbiology, University of Washington School of Medicine, Seattle 98195
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