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Teng Q, Tang L, Huang Y, Yang R, He Y, Zhang G, Zhao Y. Mutagenesis of the di-leucine motif in the cytoplasmic tail of newcastle disease virus fusion protein modulates the viral fusion ability and pathogenesis. Virol J 2023; 20:25. [PMID: 36759854 PMCID: PMC9909845 DOI: 10.1186/s12985-023-01985-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 02/06/2023] [Indexed: 02/11/2023] Open
Abstract
BACKGROUND Newcastle disease virus (NDV) is a highly infectious viral disease, which can affect chickens and many other kinds of birds. The main virulence factor of NDV, the fusion (F) protein, is located on the viral envelope and plays a major role in the virus' ability to penetrate cells and cause host cell fusion during infection. Multiple highly conserved tyrosine and di-leucine (LL) motifs in the cytoplasmic tail (CT) of the virus may contribute to F protein functionality in the viral life cycle. METHODS To examine the contribution of the LL motif in the biosynthesis, transport, and function of the F protein, we constructed and rescued a NDV mutant strain, rSG10*-F/L537A, with an L537A mutation using a reverse genetic system. Subsequently, we compared the differences in the syncytium formation ability, pathogenicity, and replication levels of wild-type rSG10* and the mutated strain. RESULTS Compared with rSG10*, rSG10*-F/L537A had attenuated syncytial formation and pathogenicity, caused by a viral budding defect. Further studies showed that the LL-motif mutation did not affect the replication, transcription, or translation of the virus genome but affected the expression of the F protein at the cell surface. CONCLUSIONS We concluded that the LL motif in the NDV F CT affected the regulation of F protein expression at the cell surface, thus modulating the viral fusion ability and pathogenic phenotype.
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Affiliation(s)
- Qingyuan Teng
- grid.22935.3f0000 0004 0530 8290Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, No. 2 Yuanmingyuan West Road, Haidian District, Beijing, 100193 China
| | - Lihua Tang
- grid.22935.3f0000 0004 0530 8290Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, No. 2 Yuanmingyuan West Road, Haidian District, Beijing, 100193 China
| | - Yahui Huang
- grid.22935.3f0000 0004 0530 8290Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, No. 2 Yuanmingyuan West Road, Haidian District, Beijing, 100193 China
| | - Ruihua Yang
- grid.22935.3f0000 0004 0530 8290Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, No. 2 Yuanmingyuan West Road, Haidian District, Beijing, 100193 China
| | - Yizhuo He
- grid.22935.3f0000 0004 0530 8290Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, No. 2 Yuanmingyuan West Road, Haidian District, Beijing, 100193 China
| | - Guozhong Zhang
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, No. 2 Yuanmingyuan West Road, Haidian District, Beijing, 100193, China.
| | - Ye Zhao
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, No. 2 Yuanmingyuan West Road, Haidian District, Beijing, 100193, China.
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2
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Genomic and Pathogenic Characteristics of Virulent Newcastle Disease Virus Isolated from Chicken in Live Bird Markets and Backyard Flocks in Kenya. Int J Microbiol 2020; 2020:4705768. [PMID: 32908524 PMCID: PMC7450340 DOI: 10.1155/2020/4705768] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 07/22/2020] [Indexed: 12/15/2022] Open
Abstract
Newcastle disease (ND) causes significant economic losses in the poultry industry in developing countries. In Kenya, despite rampant annual ND outbreaks, implementation of control strategies is hampered by a lack of adequate knowledge on the circulating and outbreak causing-NDV strains. This study reports the first complete genome sequences of NDV from backyard chicken in Kenya. The results showed that all three isolates are virulent, as assessed by the mean death time (MDT) and intracerebral pathogenicity index (ICPI) in specific antibody negative (SAN) embryonated eggs and 10-day-old chickens, respectively. Also, the polybasic amino acid sequence at the fusion-protein cleavage site had the motif 112RRQKRFV118. Histopathological findings in four-week-old SPF chicken challenged with the NDV isolates KE001, KE0811, and KE0698 showed multiple organ involvement at five days after infection with severe effects seen in lymphoid tissues and blood vessels. Analysis of genome sequences obtained from the three isolates showed that they were 15192 base pair (bp) in length and had genomic features consistent with other NDV strains, the functional sites within the coding sequence being highly conserved in the sequence of the three isolates. Amino acid residues and substitutions in the structural proteins of the three isolates were similar to the newly isolated Tanzanian NDV strain (Mbeya/MT15). A similarity matrix showed a high similarity of the isolates to NDV strains of class II genotype V (89–90%) and subgenotype Vd (95–97%). Phylogenetic analysis confirmed that the three isolates are closely related to NDV genotype V strains but form a distinct cluster together with NDV strains from the East African countries of Uganda and Tanzania to form the newly characterized subgenotype Vd. Our study provides the first description of the genomic and pathological characteristics of NDV of subgenotype Vd and lays a baseline in understanding the evolutionary dynamics of NDV and, in particular, Genotype V. This information will be useful in the development of specific markers for detection of viruses of genotype V and generation of genotype matched vaccines.
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3
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Kordyukova L. Structural and functional specificity of Influenza virus haemagglutinin and paramyxovirus fusion protein anchoring peptides. Virus Res 2017; 227:183-199. [DOI: 10.1016/j.virusres.2016.09.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 09/21/2016] [Accepted: 09/23/2016] [Indexed: 02/08/2023]
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4
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Zhou J, Xu S, Ma J, Lei W, Liu K, Liu Q, Ren Y, Xue C, Cao Y. Recombinant influenza A H3N2 viruses with mutations of HA transmembrane cysteines exhibited altered virological characteristics. Virus Genes 2013; 48:273-82. [PMID: 24272698 DOI: 10.1007/s11262-013-1011-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 11/06/2013] [Indexed: 01/20/2023]
Abstract
Influenza A H3N2 virus as the cause of 1968 pandemic has since been circulating in human and swine. Our earlier study has shown that mutations of one or two cysteines in the transmembrane domain of H3 hemagglutinin (HA) affected the thermal stability and fusion activity of recombinant HA proteins. Here, we report the successful generation of three recombinant H3N2 mutant viruses (C540S, C544L, and 2C/SL) with mutations of one or two transmembrane cysteines of HA in the background of A/swine/Guangdong/01/98 [H3N2] using reverse genetics, indicating that the mutated cysteines were not essential for virus assembly and growth. Further characterization revealed that recombinant H3N2 mutant viruses exhibited larger plaque sizes, increased growth rate in cells, enhanced fusion activity, reduced thermal and acidic resistances, and increased virulence in embryonated eggs. These results demonstrated that the transmembrane cysteines (C540 and C544) in H3 HA have profound effects on the virological features of H3N2 viruses.
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Affiliation(s)
- Jianqiang Zhou
- State Key Laboratory of Biocontrol, Life Sciences School, Guangzhou Higher Education Mega Center, Sun Yat-sen University, Guangzhou, 510006, People's Republic of China
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5
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Ren G, Zhuang Y, Tian K, Li H, Diao X, Wang M, Zhou N, Wang Z. Acidic amino acids increase fusion activity in the specific fusion domain of Newcastle disease virus fusion protein. Can J Microbiol 2013; 59:641-4. [DOI: 10.1139/cjm-2013-0133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To explore the effects of amino acids Gln and Asn within the specific fusion domain of fusion (F) protein on the specific membrane fusion in Newcastle disease virus (NDV), the mutants Q204E–Q205E and N245D were constructed in the specific fusion domain of F protein. The mutant genes were co-expressed with homologous or heterologous hemagglutinin–neuraminidase (HN) in BHK21 cells. Cell fusion functions of mutants were analyzed with Giemsa staining and reporter gene methods. Cell surface expression efficiency was analyzed with immunofluorescence assay and fluorescence-activated cell sorter analysis. Co-immunoprecipitation was performed to analyze the interaction of mutant F proteins with the homotypic HN protein. Both Q204E–Q205E and N245D mutations caused increased cell–cell fusion activity when they were co-expressed with homotypic HN protein. The mutant F proteins had slight changes in cell surface expression compared with that of wild-type F protein. The interactions of Q204E–Q205E or N245D with their homotypic HN increased significantly (P < 0.01) compared with the wild-type F protein. Neither Q204–Q205E nor N245D caused cell fusion in the presence of heterologous HN protein. Our data suggested that the residues Q204, Q205, and N245 play a critical role in the regulation of cell fusion. They may decrease the interaction of wild-type NDV F and NDV HN to suppress the fusion activity for survival of the infected host, which may enable a persistent virus infection and long-term virus reproduction and spread.
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Affiliation(s)
- Guijie Ren
- Institute of Biochemistry and Molecular Biology, School of Medicine, Shandong University, Jinan 250012, People’s Republic of China
| | - Yunlong Zhuang
- Blood Center of Shandong Province, Jinan 250014, People’s Republic of China
| | - Keli Tian
- Institute of Biochemistry and Molecular Biology, School of Medicine, Shandong University, Jinan 250012, People’s Republic of China
| | - Huiyu Li
- Bio-technology Department, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People’s Republic of China
| | - Xueqin Diao
- Institute of Biochemistry and Molecular Biology, School of Medicine, Shandong University, Jinan 250012, People’s Republic of China
| | - Miaomiao Wang
- Institute of Biochemistry and Molecular Biology, School of Medicine, Shandong University, Jinan 250012, People’s Republic of China
| | - Nan Zhou
- Institute of Biochemistry and Molecular Biology, School of Medicine, Shandong University, Jinan 250012, People’s Republic of China
| | - Zhiyu Wang
- Department of Virology, School of Public Health, Shandong University, Jinan 250012, People’s Republic of China
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Point mutations in the paramyxovirus F protein that enhance fusion activity shift the mechanism of complement-mediated virus neutralization. J Virol 2013; 87:9250-9. [PMID: 23785199 DOI: 10.1128/jvi.01111-13] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Parainfluenza virus 5 (PIV5) activates and is neutralized by the alternative pathway (AP) in normal human serum (NHS) but not by heat-inactivated (HI) serum. We have tested the relationship between the fusion activity within the PIV5 F protein, the activation of complement pathways, and subsequent complement-mediated virus neutralization. Recombinant PIV5 viruses with enhanced fusion activity were generated by introducing point mutations in the F fusogenic peptide (G3A) or at a distal site near the F transmembrane domain (S443P). In contrast to wild-type (WT) PIV5, the mutant G3A and S443P viruses were neutralized by both NHS and HI serum. Unlike WT PIV5, hyperfusogenic G3A and S443P viruses were potent C4 activators, C4 was deposited on NHS-treated mutant virions, and the mutants were neutralized by factor B-depleted serum but not by C4-depleted serum. Antibodies purified from HI human serum were sufficient to neutralize both G3A and S443P viruses in vitro but were ineffective against WT PIV5. Electron microscopy data showed greater deposition of purified human antibodies on G3A and S443P virions than on WT PIV5 particles. These data indicate that single amino acid changes that enhance the fusion activity of the PIV5 F protein shift the mechanism of complement activation in the context of viral particles or on the surface of virus-infected cells, due to enhanced binding of antibodies. We present general models for the relationship between enhanced fusion activity in the paramyxovirus F protein and increased susceptibility to antibody-mediated neutralization.
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7
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Selection and characterization of human respiratory syncytial virus escape mutants resistant to a polyclonal antiserum raised against the F protein. Arch Virol 2012; 157:1071-80. [PMID: 22411099 DOI: 10.1007/s00705-012-1274-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Accepted: 02/02/2012] [Indexed: 10/28/2022]
Abstract
A human respiratory syncytial virus (HRSV) neutralization escape mutant was obtained after 56 serial passages in the presence of a polyclonal antiserum raised against the F protein. Nucleotide sequence analysis of this escape mutant virus revealed two amino acid substitutions: Asn268Ile and Val533Met. When this virus was allowed to grow in the absence of the anti-F polyclonal serum, only the mutation Asn268Ile was stably maintained. Both the double and single escape mutant viruses lost reactivity with mAbs belonging to antigenic site II of the fusion protein of RSV. Mutation Asn268Ile has already been reported in RS viruses that are resistant to mAbs 47F and 11 and palivizumab (PZ). We have thus identified a novel mutation (Val533Met) in the transmembrane domain of the F protein that was selected under immune pressure.
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8
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Side chain packing below the fusion peptide strongly modulates triggering of the Hendra virus F protein. J Virol 2010; 84:10928-32. [PMID: 20702638 DOI: 10.1128/jvi.01108-10] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Triggering of the Hendra virus fusion (F) protein is required to initiate the conformational changes which drive membrane fusion, but the factors which control triggering remain poorly understood. Mutation of a histidine predicted to lie near the fusion peptide to alanine greatly reduced fusion despite wild-type cell surface expression levels, while asparagine substitution resulted in a moderate restoration in fusion levels. Slowed kinetics of six-helix bundle formation, as judged by sensitivity to heptad repeat B-derived peptides, was observed for all H372 mutants. These data suggest that side chain packing beneath the fusion peptide is an important regulator of Hendra virus F triggering.
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9
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Conserved leucine residue in the head region of morbillivirus fusion protein regulates the large conformational change during fusion activity. Biochemistry 2009; 48:9112-21. [PMID: 19705836 DOI: 10.1021/bi9008566] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Paramyxovirus cell entry is controlled by the concerted action of two viral envelope glycoproteins, the fusion (F) and the receptor-binding (H) proteins, which together with a cell surface receptor mediate plasma membrane fusion activity. The paramyxovirus F protein belongs to class I viral fusion proteins which typically contain two heptad repeat regions (HR). Particular to paramyxovirus F proteins is a long intervening sequence (IS) located between both HR domains. To investigate the role of the IS domain in regulating fusogenicity, we mutated in the canine distemper virus (CDV) F protein IS domain a highly conserved leucine residue (L372) previously reported to cause a hyperfusogenic phenotype. Beside one F mutant, which elicited significant defects in processing, transport competence, and fusogenicity, all remaining mutants were characterized by enhanced fusion activity despite normal or slightly impaired processing and cell surface targeting. Using anti-CDV-F monoclonal antibodies, modified conformational F states were detected in F mutants compared to the parental protein. Despite these structural differences, coimmunoprecipitation assays did not reveal any drastic modulation in F/H avidity of interaction. However, we found that F mutants had significantly enhanced fusogenicity at low temperature only, suggesting that they folded into conformations requiring less energy to activate fusion. Together, these data provide strong biochemical and functional evidence that the conserved leucine 372 at the base of the HRA coiled-coil of F(wt) controls the stabilization of the prefusogenic state, restraining the conformational switch and thereby preventing extensive cell-cell fusion activity.
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10
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Plattet P, Cherpillod P, Wiener D, Zipperle L, Vandevelde M, Wittek R, Zurbriggen A. Signal peptide and helical bundle domains of virulent canine distemper virus fusion protein restrict fusogenicity. J Virol 2007; 81:11413-25. [PMID: 17686846 PMCID: PMC2045578 DOI: 10.1128/jvi.01287-07] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Persistence in canine distemper virus (CDV) infection is correlated with very limited cell-cell fusion and lack of cytolysis induced by the neurovirulent A75/17-CDV compared to that of the cytolytic Onderstepoort vaccine strain. We have previously shown that this difference was at least in part due to the amino acid sequence of the fusion (F) protein (P. Plattet, J. P. Rivals, B. Zuber, J. M. Brunner, A. Zurbriggen, and R. Wittek, Virology 337:312-326, 2005). Here, we investigated the molecular mechanisms of the neurovirulent CDV F protein underlying limited membrane fusion activity. By exchanging the signal peptide between both F CDV strains or replacing it with an exogenous signal peptide, we demonstrated that this domain controlled intracellular and consequently cell surface protein expression, thus indirectly modulating fusogenicity. In addition, by serially passaging a poorly fusogenic virus and selecting a syncytium-forming variant, we identified the mutation L372W as being responsible for this change of phenotype. Intriguingly, residue L372 potentially is located in the helical bundle domain of the F(1) subunit. We showed that this mutation drastically increased fusion activity of F proteins of both CDV strains in a signal peptide-independent manner. Due to its unique structure even among morbilliviruses, our findings with respect to the signal peptide are likely to be specifically relevant to CDV, whereas the results related to the helical bundle add new insights to our growing understanding of this class of F proteins. We conclude that different mechanisms involving multiple domains of the neurovirulent A75/17-CDV F protein act in concert to limit fusion activity, preventing lysis of infected cells, which ultimately may favor viral persistence.
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Affiliation(s)
- Philippe Plattet
- Department of Clinical Veterinary Medicine, Bremgartenstrasse 109a, 3001 Bern, Switzerland
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11
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Seth S, Skountzou I, Gernert KM, Compans RW. Fusogenic variants of a noncytopathic paramyxovirus. J Virol 2007; 81:4286-97. [PMID: 17287262 PMCID: PMC1866114 DOI: 10.1128/jvi.01623-06] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
SER virus is a type 5 parainfluenza virus that does not exhibit syncytium formation, in contrast to most other paramyxoviruses. This property has been attributed, at least in part, to the presence of an extension of the cytoplasmic tail (CT) of the SER F protein, as truncations or mutations of this region resulted in enhanced fusion. In this study we used repeated passage to select for mutant SER viruses, which were found to be fusogenic. The mutant viruses replicated at levels comparable to or higher than the wild-type SER virus and caused plaque formation, in contrast to the wild-type virus which does not form plaques. The mutants differed strikingly in their plaque sizes. The F genes of mutant viruses were cloned and sequenced and shared some mutations, including a proline-to-leucine change at position 22 and an isoleucine-to-leucine substitution at position 191; other changes that were specific to each mutant were also found. The HN proteins of mutant viruses also showed mutations spanning the length of the protein whereas the M protein showed a consistent mutation, threonine to isoleucine, at position 129. The structure of the F protein was used to identify residues involved in the mutant phenotypes in terms of their location and proximity to heptad repeat domains.
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Affiliation(s)
- Shaguna Seth
- Department of Microbiology and Immunology, Emory University School of Medicine, 1510 Clifton Road, Atlanta, GA 30322, USA
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12
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Connolly SA, Lamb RA. Paramyxovirus fusion: real-time measurement of parainfluenza virus 5 virus-cell fusion. Virology 2006; 355:203-12. [PMID: 16916528 DOI: 10.1016/j.virol.2006.07.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Revised: 06/30/2006] [Accepted: 07/13/2006] [Indexed: 11/20/2022]
Abstract
Although cell-cell fusion assays are useful surrogate methods for studying virus fusion, differences between cell-cell and virus-cell fusion exist. To examine paramyxovirus fusion in real time, we labeled viruses with fluorescent lipid probes and monitored virus-cell fusion by fluorimetry. Two parainfluenza virus 5 (PIV5) isolates (W3A and SER) and PIV5 containing mutations within the fusion protein (F) were studied. Fusion was specific and temperature-dependent. Compared to many low pH-dependent viruses, the kinetics of PIV5 fusion was slow, approaching completion within several minutes. As predicted from cell-cell fusion assays, virus containing an F protein with an extended cytoplasmic tail (rSV5 F551) had reduced fusion compared to wild-type virus (W3A). In contrast, virus-cell fusion for SER occurred at near wild-type levels, despite the fact that this isolate exhibits a severely reduced cell-cell fusion phenotype. These results support the notion that virus-cell and cell-cell fusion have significant differences.
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Affiliation(s)
- Sarah A Connolly
- Howard Hughes Medical Institute, Northwestern University, Evanston, IL 60208-3500, USA
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13
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Kong BW, Foster LK, Foster DN. Comparison of avian cell substrates for propagating subtype C avian metapneumovirus. Virus Res 2006; 116:58-68. [PMID: 16194579 DOI: 10.1016/j.virusres.2005.08.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2005] [Revised: 08/25/2005] [Accepted: 08/26/2005] [Indexed: 11/25/2022]
Abstract
Avian metapneumovirus (AMPV) is a respiratory viral pathogen that causes turkey rhinotracheitis (TRT) or swollen head syndrome (SHS) in chickens. AMPV was first isolated in South Africa during the early 1970s and has subsequently spread worldwide during the 1980s to include Europe, Asia, and South America. In 1996, a genetically distinct AMPV subgroup C was isolated in the US following an outbreak of TRT. Vero cells are currently the best available substrate for AMPV propagation but are of non-avian origin. A number of different avian cell substrates have been compared to determine which is the most suitable for the propagation of AMPV to sufficiently high titers. Of the cell substrates tested, primary turkey turbinate and kidney and chicken kidney cells produced titers equal to or greater than Vero cells. Turkey turbinate and kidney epithelial cells that were life-span extended by the ectopic expression of human telomerase catalytic subunit (HTERT) initially displayed AMPV titers comparable to Vero cell controls, but declined in virus production with increased passage in culture. Interestingly, plaques emanating from Vero propagated virus were relatively small and dispersed, when analyzed by immunofluorescent assays (IFA), while both turkey turbinate and kidney cell propagated AMPV produced larger plaques. Even with these differences, there were no changes in the predicted amino acid sequences of the nucleocapsid (N) and phosphoprotein (P) genes of AMPV propagated in either turkey turbinate or Vero host cells. However, the fusion (F) gene showed 11 amino acid differences (98.7% identity) between the two host cell types. These results suggest that AMPV propagated in homologous avian cellular substrates may produce more infectious virus with possibly more effective fusion activity, compared to Vero cell propagation.
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Affiliation(s)
- Byung-Whi Kong
- Department of Animal Science, University of Minnesota, 495 AnSci/VetMed, 1988 Fitch Ave., St. Paul, 55108, USA
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Pantua H, McGinnes LW, Leszyk J, Morrison TG. Characterization of an alternate form of Newcastle disease virus fusion protein. J Virol 2005; 79:11660-70. [PMID: 16140743 PMCID: PMC1212644 DOI: 10.1128/jvi.79.18.11660-11670.2005] [Citation(s) in RCA: 7] [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 sequence and structure of the Newcastle disease virus (NDV) fusion (F) protein are consistent with its classification as a type 1 glycoprotein. We have previously reported, however, that F protein can be detected in at least two topological forms with respect to membranes in both a cell-free protein synthesizing system containing membranes and infected COS-7 cells (J. Virol. 77:1951-1963, 2003). One form is the classical type 1 glycoprotein, while the other is a polytopic form in which approximately 200 amino acids of the amino-terminal end as well as the cytoplasmic domain (CT) are translocated across membranes. Furthermore, we detected CT sequences on surfaces of F protein-expressing cells, and antibodies specific for these sequences inhibited red blood cell fusion to hemagglutinin-neuraminidase and F protein-expressing cells, suggesting a role for surface-expressed CT sequences in cell-cell fusion. Extending these findings, we have found that the alternate form of the F protein can also be detected in infected and transfected avian cells, the natural host cells of NDV. Furthermore, the alternate form of the F protein was also found in virions released from both infected COS-7 cells and avian cells by Western analysis. Mass spectrometry confirmed its presence in virions released from avian cells. Two different polyclonal antibodies raised against sequences of the CT domain of the F protein slowed plaque formation in both avian and COS-7 cells. Antibody specific for the CT domain also inhibited single-cycle infections, as detected by immunofluorescence of viral proteins in infected cells. The potential roles of this alternate form of the NDV F protein in infection are discussed.
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Affiliation(s)
- Homer Pantua
- Department of Molecular Genetics and Microbiology, University of Massachusetts Medical School, Rm. S5-250, 55 Lake Avenue North, Worcester, MA 01655, USA
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Plattet P, Rivals JP, Zuber B, Brunner JM, Zurbriggen A, Wittek R. The fusion protein of wild-type canine distemper virus is a major determinant of persistent infection. Virology 2005; 337:312-26. [PMID: 15893783 DOI: 10.1016/j.virol.2005.04.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2005] [Revised: 02/10/2005] [Accepted: 04/08/2005] [Indexed: 10/25/2022]
Abstract
The wild-type A75/17 canine distemper virus (CDV) strain induces a persistent infection in the central nervous system but infects cell lines very inefficiently. In contrast, the genetically more distant Onderstepoort CDV vaccine strain (OP-CDV) induces extensive syncytia formation. Here, we investigated the roles of wild-type fusion (F(WT)) and attachment (H(WT)) proteins in Vero cells expressing, or not, the canine SLAM receptor by transfection experiments and by studying recombinants viruses expressing different combinations of wild-type and OP-CDV glycoproteins. We show that low fusogenicity is not due to a defect of the envelope proteins to reach the cell surface and that H(WT) determines persistent infection in a receptor-dependent manner, emphasizing the role of SLAM as a potent enhancer of fusogenicity. However, importantly, F(WT) reduced cell-to-cell fusion independently of the cell surface receptor, thus demonstrating that the fusion protein of the neurovirulent A75/17-CDV strain plays a key role in determining persistent infection.
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Affiliation(s)
- Philippe Plattet
- Institut de Biotechnologie, University of Lausanne, Bâtiment de Biologie, CH-1015 Lausanne, Switzerland
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Ullman DE, Whitfield AE, German TL. Thrips and tospoviruses come of age: mapping determinants of insect transmission. Proc Natl Acad Sci U S A 2005; 102:4931-2. [PMID: 15795369 PMCID: PMC555985 DOI: 10.1073/pnas.0501341102] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Diane E Ullman
- Department of Entomology, University of California, Davis, CA 95616, USA.
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