1
|
Kuang G, Xu Z, Wang J, Gao Z, Yang W, Wu W, Liang G, Shi M, Feng Y. Nelson Bay Reovirus Isolated from Bats and Blood-Sucking Arthropods Collected in Yunnan Province, China. Microbiol Spectr 2023; 11:e0512222. [PMID: 37306586 PMCID: PMC10433815 DOI: 10.1128/spectrum.05122-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 05/22/2023] [Indexed: 06/13/2023] Open
Abstract
Nelson Bay reovirus (NBV) is an emerging zoonotic virus that can cause acute respiratory disease in humans. These viruses are mainly discovered in Oceania, Africa, and Asia, and bats have been identified as their main animal reservoir. However, despite recent expansion of diversity for NBVs, the transmission dynamics and evolutionary history of NBVs are still unclear. This study successfully isolated two NBV strains (MLBC1302 and MLBC1313) from blood-sucking bat fly specimens (Eucampsipoda sundaica) and one (WDBP1716) from the spleen specimen of a fruit bat (Rousettus leschenaultii), which were collected at the China-Myanmar border area of Yunnan Province. Syncytia cytopathic effects (CPE) were observed in BHK-21 and Vero E6 cells infected with the three strains at 48 h postinfection. Electron micrographs of ultrathin sections showed numerous spherical virions with a diameter of approximately 70 nm in the cytoplasm of infected cells. The complete genome nucleotide sequence of the viruses was determined by metatranscriptomic sequencing of infected cells. Phylogenetic analysis demonstrated that the novel strains were closely related to Cangyuan orthoreovirus, Melaka orthoreovirus, and human-infecting Pteropine orthoreovirus HK23629/07. Simplot analysis revealed the strains originated from complex genomic reassortment among different NBVs, suggesting the viruses experienced a high reassortment rate. In addition, strains successfully isolated from bat flies also implied that blood-sucking arthropods might serve as potential transmission vectors. IMPORTANCE Bats are the reservoir of many viral pathogens with strong pathogenicity, including NBVs. Nevertheless, it is unclear whether arthropod vectors are involved in transmitting NBVs. In this study, we successfully isolated two NBV strains from bat flies collected from the body surface of bats, which implies that they may be vectors for virus transmission between bats. While the potential threat to humans remains to be determined, evolutionary analyses involving different segments revealed that the novel strains had complex reassortment histories, with S1, S2, and M1 segments highly similar to human pathogens. Further experiments are required to determine whether more NBVs are vectored by bat flies, their potential threat to humans, and transmission dynamics.
Collapse
Affiliation(s)
- Guopeng Kuang
- Yunnan Provincial Key Laboratory for Zoonosis Control and Prevention, Yunnan Institute of Endemic Disease Control and Prevention, Dali, China
| | - Ziqian Xu
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Jing Wang
- Centre for Infection and Immunity Studies, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
| | - Zhangjin Gao
- Yunnan Provincial Key Laboratory for Zoonosis Control and Prevention, Yunnan Institute of Endemic Disease Control and Prevention, Dali, China
- School of Public Health, Dali University, Dali, China
| | - Weihong Yang
- Yunnan Provincial Key Laboratory for Zoonosis Control and Prevention, Yunnan Institute of Endemic Disease Control and Prevention, Dali, China
| | - Weichen Wu
- Centre for Infection and Immunity Studies, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
| | - Guodong Liang
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Mang Shi
- Centre for Infection and Immunity Studies, School of Medicine, Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
| | - Yun Feng
- Yunnan Provincial Key Laboratory for Zoonosis Control and Prevention, Yunnan Institute of Endemic Disease Control and Prevention, Dali, China
- School of Public Health, Dali University, Dali, China
- College of Global Change and Earth System Science, Beijing Normal University, Beijing, China
| |
Collapse
|
2
|
López CB. Defective Viral Particles. Virology 2021. [DOI: 10.1002/9781119818526.ch5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
3
|
Reverse Genetics for Fusogenic Bat-Borne Orthoreovirus Associated with Acute Respiratory Tract Infections in Humans: Role of Outer Capsid Protein σC in Viral Replication and Pathogenesis. PLoS Pathog 2016; 12:e1005455. [PMID: 26901882 PMCID: PMC4762779 DOI: 10.1371/journal.ppat.1005455] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 01/24/2016] [Indexed: 12/26/2022] Open
Abstract
Nelson Bay orthoreoviruses (NBVs) are members of the fusogenic orthoreoviruses and possess 10-segmented double-stranded RNA genomes. NBV was first isolated from a fruit bat in Australia more than 40 years ago, but it was not associated with any disease. However, several NBV strains have been recently identified as causative agents for respiratory tract infections in humans. Isolation of these pathogenic bat reoviruses from patients suggests that NBVs have evolved to propagate in humans in the form of zoonosis. To date, no strategy has been developed to rescue infectious viruses from cloned cDNA for any member of the fusogenic orthoreoviruses. In this study, we report the development of a plasmid-based reverse genetics system free of helper viruses and independent of any selection for NBV isolated from humans with acute respiratory infection. cDNAs corresponding to each of the 10 full-length RNA gene segments of NBV were cotransfected into culture cells expressing T7 RNA polymerase, and viable NBV was isolated using a plaque assay. The growth kinetics and cell-to-cell fusion activity of recombinant strains, rescued using the reverse genetics system, were indistinguishable from those of native strains. We used the reverse genetics system to generate viruses deficient in the cell attachment protein σC to define the biological function of this protein in the viral life cycle. Our results with σC-deficient viruses demonstrated that σC is dispensable for cell attachment in several cell lines, including murine fibroblast L929 cells but not in human lung epithelial A549 cells, and plays a critical role in viral pathogenesis. We also used the system to rescue a virus that expresses a yellow fluorescent protein. The reverse genetics system developed in this study can be applied to study the propagation and pathogenesis of pathogenic NBVs and in the generation of recombinant NBVs for future vaccines and therapeutics. Nelson Bay orthoreoviruses (NBVs) are members of the fusogenic orthoreoviruses that have various host species, including reptiles, birds, and mammals. Recently, several NBV strains have been isolated from patients with acute respiratory tract infections. Isolation of these pathogenic reoviruses raises concerns about the potential emerging infections of bat-borne orthoreoviruses in humans. The development of an entirely plasmid-based reverse genetics system for double-stranded RNA viruses has trailed other systems of major animal RNA virus groups because of the technical complexities involved in the manipulation of genomes composed of 10 or more segments. In this study, we developed a plasmid-based reverse genetics system for a pathogenic NBV strain. We used this system to generate viruses incapable of expressing the cell attachment protein σC and to rescue a replication-competent virus that expresses a yellow fluorescent protein. Our studies using σC-deficient viruses suggest that NBVs may engage multiple independent viral ligands and cellular receptors for efficient cell attachment and viral pathogenesis, thus providing new insight into the biology of orthoreoviruses. The reverse genetics approach described in this study can be exploited for fusogenic orthoreovirus biology and used to develop vaccines, diagnostics, and therapeutics.
Collapse
|
4
|
Stotzky G. Influence of Soil Mineral Colloids on Metabolic Processes, Growth, Adhesion, and Ecology of Microbes and Viruses. SSSA SPECIAL PUBLICATIONS 2015. [DOI: 10.2136/sssaspecpub17.c10] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- G. Stotzky
- Laboratory of Microbial Ecology, Dep. of Biology; New York University; New York NY 10003 USA
| |
Collapse
|
5
|
Hu T, Qiu W, He B, Zhang Y, Yu J, Liang X, Zhang W, Chen G, Zhang Y, Wang Y, Zheng Y, Feng Z, Hu Y, Zhou W, Tu C, Fan Q, Zhang F. Characterization of a novel orthoreovirus isolated from fruit bat, China. BMC Microbiol 2014; 14:293. [PMID: 25433675 PMCID: PMC4264558 DOI: 10.1186/s12866-014-0293-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 11/11/2014] [Indexed: 01/25/2023] Open
Abstract
Background In recent years novel human respiratory disease agents have been described for Southeast Asia and Australia. The causative pathogens were classified as pteropine orthoreoviruses with a strong phylogenetic relationship to orthoreoviruses of bat origin. Results In this report, we isolated a novel Melaka-like reovirus (named “Cangyuan virus”) from intestinal content samples of one fruit bat residing in China’s Yunnan province. Phylogenetic analysis of the whole Cangyuan virus genome sequences of segments L, M and S demonstrated the genetic diversity of the Cangyuan virus. In contrast to the L and M segments, the phylogenetic trees for the S segments of Cangyuan virus demonstrated a greater degree of heterogeneity. Conclusions Phylogenetic analysis indicated that the Cangyuan virus was a novel orthoreovirus and substantially different from currently known members of Pteropine orthoreovirus (PRV) species group. Electronic supplementary material The online version of this article (doi:10.1186/s12866-014-0293-4) contains supplementary material, which is available to authorized users.
Collapse
|
6
|
Voon K, Chua KB, Yu M, Crameri G, Barr JA, Malik Y, Wang LF. Evolutionary relationship of the L- and M-class genome segments of bat-borne fusogenic orthoreoviruses in Malaysia and Australia. J Gen Virol 2011; 92:2930-2936. [PMID: 21849518 DOI: 10.1099/vir.0.033498-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
We previously described three new Malaysian orthoreoviruses designated Pulau virus, Melaka virus and Kampar virus. Melaka and Kampar viruses were shown to cause respiratory disease in humans. These viruses, together with Nelson Bay virus, isolated from Australian bats, are tentatively classified as different strains within the species Pteropine orthoreovirus (PRV), formerly known as Nelson Bay orthoreovirus, based on the small (S) genome segments. Here we report the sequences of the large (L) and medium (M) segments, thus completing the whole-genome characterization of the four PRVs. All L and M segments were highly conserved in size and sequence. Conserved functional motifs previously identified in other orthoreovirus gene products were also found in the deduced proteins encoded by the cognate segments of these viruses. Detailed sequence analysis identified two genetic lineages divided into the Australian and Malaysian PRVs, and potential genetic reassortment among the M and S segments of the three Malaysian viruses.
Collapse
Affiliation(s)
- Kenny Voon
- International Medical University, Bukit Jalil, Kuala Lumpur, Malaysia
| | - Kaw Bing Chua
- National Public Health Laboratory, Sg. Buloh, Selangor, Malaysia.,International Medical University, Bukit Jalil, Kuala Lumpur, Malaysia
| | - Meng Yu
- CSIRO Livestock Industries, Australian Animal Health Laboratory, Geelong, Australia
| | - Gary Crameri
- CSIRO Livestock Industries, Australian Animal Health Laboratory, Geelong, Australia
| | - Jennifer A Barr
- CSIRO Livestock Industries, Australian Animal Health Laboratory, Geelong, Australia
| | - Yasmin Malik
- International Medical University, Bukit Jalil, Kuala Lumpur, Malaysia
| | - Lin-Fa Wang
- CSIRO Livestock Industries, Australian Animal Health Laboratory, Geelong, Australia
| |
Collapse
|
7
|
Pirkooh AA, Shahrabadi MS, Monavari H, Shafiei A. Reovirus inhibits poliovirus replication upon superinfection. Intervirology 2011; 55:62-7. [PMID: 21454948 DOI: 10.1159/000324033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Accepted: 12/14/2010] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE Viral interference has been demonstrated in different systems, such as the effect of enterovirus infection on live-attenuated oral polio vaccine. In this study, the effect of reovirus which could exist in the human intestinal tract on poliovirus vaccine strains was investigated and could be an important factor to consider in oral polio vaccination. METHODS Cells were infected with reovirus, then superinfected with poliovirus. The amount of viral yields was measured by the TCID(50) and plaque assay methods. Polioviral RNA synthesis was studied by real-time RT-PCR and the viral RNA load was calculated. Viral protein synthesis was determined using the techniques of immunoflourescent staining and PAGE followed by the immunoblotting experiment. RESULTS Poliovirus superinfection of reovirus-infected cells resulted in inhibition of poliovirus replication. It was found that the inhibitory effect of reovirus was after establishment of its infection (2 h postinfection). There was no competition between the two viruses for cell attachment but poliovirus RNA and protein synthesis were inhibited. CONCLUSION Infection of cells with reovirus could interfere with the growth of poliovirus upon superinfection. This phenomenon could be important to consider when using attenuated poliovirus vaccine.
Collapse
Affiliation(s)
- Angila Ataei Pirkooh
- Department of Virology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | | | | | | |
Collapse
|
8
|
Mohd Jaafar F, Goodwin AE, Belhouchet M, Merry G, Fang Q, Cantaloube JF, Biagini P, de Micco P, Mertens PPC, Attoui H. Complete characterisation of the American grass carp reovirus genome (genus Aquareovirus: family Reoviridae) reveals an evolutionary link between aquareoviruses and coltiviruses. Virology 2008; 373:310-21. [PMID: 18191982 DOI: 10.1016/j.virol.2007.12.006] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2007] [Revised: 11/27/2007] [Accepted: 12/06/2007] [Indexed: 11/18/2022]
Abstract
An aquareovirus was isolated from several fish species in the USA (including healthy golden shiners) that is not closely related to members of species Aquareovirus A, B and C. The virus, which is atypical (does not cause syncytia in cell cultures at neutral pH), was implicated in a winter die-off of grass carp fingerlings and has therefore been called 'American grass carp reovirus' (AGCRV). Complete nucleotide sequence analysis of the AGCRV genome and comparisons to the other aquareoviruses showed that it is closely related to golden ide reovirus (GIRV) (>92% amino acid [aa] identity in VP5(NTPase) and VP2(Pol)). However, comparisons with grass carp reovirus (Aquareovirus C) and chum salmon reovirus (Aquareovirus A) showed only 22% to 76% aa identity in different viral proteins. These findings have formed the basis for the recognition of AGCRV and GIRV as members of a new Aquareovirus species 'Aquareovirus G' by ICTV. Further sequence comparisons to other members of the family Reoviridae suggest that there has been an 'evolutionary jump,' involving a change in the number of genome segments, between the aquareoviruses (11 segments) and coltiviruses (12 segments). Segment 7 of AGRCV encodes two proteins, from two distinct ORFs, which are homologues of two Coltivirus proteins encoded by genome segments 9 and 12. A similar model has previously been reported for the rotaviruses and seadornaviruses.
Collapse
Affiliation(s)
- Fauziah Mohd Jaafar
- Department of Arbovirology, Institute for Animal Health, Pirbright, Woking, Surrey, GU24 0NF, UK
| | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Lymperopoulos K, Noad R, Tosi S, Nethisinghe S, Brierley I, Roy P. Specific binding of Bluetongue virus NS2 to different viral plus-strand RNAs. Virology 2006; 353:17-26. [PMID: 16872657 PMCID: PMC7116519 DOI: 10.1016/j.virol.2006.04.022] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2005] [Revised: 12/15/2005] [Accepted: 04/17/2006] [Indexed: 11/30/2022]
Abstract
The Reoviridae have double-stranded RNA genomes of 10-12 segments, each in a single copy in the mature virion. The basis of genome segment sorting during virus assembly that ensures each virus particle contains the complete viral genome is unresolved. Bluetongue virus (BTV) NS2 is a single-stranded RNA-binding protein that forms inclusion bodies in infected cells. Here, we demonstrate that the specific interaction between NS2 and a stem-loop structure present in BTV S10 RNA, and phylogenetically conserved in other BTV serotypes, is abolished by mutations predicted to disrupt the structure. Subsequently, we mapped RNA regions in three other genomic segments of BTV that are bound preferentially by NS2. However, structure probing of these RNAs did not reveal secondary structure motifs that obviously resembled the stem-loop implicated in the NS2-S10 interaction. In addition, the specific binding by NS2 to two different viral RNAs was found to occur independently. Together, these data support the hypothesis that the recognition by NS2 of different RNA structures may be the basis for discrimination between viral RNAs during virus assembly.
Collapse
Affiliation(s)
- Kostas Lymperopoulos
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | | | | | | | | | | |
Collapse
|
10
|
Affiliation(s)
- K M Coombs
- Department of Medical Microbiology, University of Manitoba, Winnipeg, Canada
| |
Collapse
|
11
|
Keirstead ND, Coombs KM. Absence of superinfection exclusion during asynchronous reovirus infections of mouse, monkey, and human cell lines. Virus Res 1998; 54:225-35. [PMID: 9696130 PMCID: PMC7126977 DOI: 10.1016/s0168-1702(98)00023-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Reovirus is a gastroenteric virus with a genome that consists of ten segments of double-stranded RNA. The segmented nature of the genome allows for genetic mixing when cells are simultaneously infected with two different viral serotypes. The ability of viral reassortment to take place in asynchronous infections has not previously been investigated with mammalian reoviruses. In this study, five different cell lines, representing mouse, monkey, and human, were infected synchronously or asynchronously with various sets of two different temperature-sensitive (ts) reovirus mutants in order to study the genetic interactions which occur. Recombinant viruses were detected at high frequency when infection by the two different ts mutants was separated by as much as 24 h, suggesting that superinfection exclusion does not play a role in reovirus mixed infections. The apparent lack of superinfection exclusion in reovirus infections may have important implications in its evolution.
Collapse
Affiliation(s)
| | - Kevin M Coombs
- Corresponding author. Tel: +1 204 7893309; fax: +1 204 7893926;
| |
Collapse
|
12
|
Abstract
The precise genetic and molecular determ inants of viral virulence are poorly understood. Genetic studies with influenza and reovirus have indicated that virulence is multigenic. The high frequency of m utation of RNA viruses can complicate genetic analyses of virulence, resulting in phenotypes that are difficult to interpret. The ease with which the reoviruses reassort genome segments has made it possible to isolate reassortants from parental viruses causing different patterns of anim al disease. It has thus been feasible to show that each of the three outer capsid proteins plays a m ajor role in the pathogenesis of anim al infection: the viral haem agglutinin determines the specificity of the im mune response and cell and tissue tropism ; the p ic protein plays a central role in determ ining yield at portals of entry as well as in differentiated tissues; the δ3 protein inhibits host m acrom olecular synthesis. Thus virulence is clearly multigenic, with each of the viral components playing distinct roles.
Collapse
|
13
|
Joklik WK, Roner MR. Molecular recognition in the assembly of the segmented reovirus genome. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1996; 53:249-81. [PMID: 8650305 DOI: 10.1016/s0079-6603(08)60147-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- W K Joklik
- Department of Microbiology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | | |
Collapse
|
14
|
Roner MR, Lin PN, Nepluev I, Kong LJ, Joklik WK. Identification of signals required for the insertion of heterologous genome segments into the reovirus genome. Proc Natl Acad Sci U S A 1995; 92:12362-6. [PMID: 8618901 PMCID: PMC40357 DOI: 10.1073/pnas.92.26.12362] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
In cells simultaneously infected with any two of the three reovirus serotypes ST1, ST2, and ST3, up to 15% of the yields are intertypic reassortants that contain all possible combinations of parental genome segments. We have now found that not all genome segments in reassortants are wild type. In reassortants that possess more ST1 than ST3 genome segments, all ST1 genome segments appear to be wild type, but the incoming ST3 genome segments possess mutations that make them more similar to the ST1 genome segments that they replace. In reassortants resulting from crosses of the more distantly related ST3 and ST2 viruses that possess a majority of ST3 genome segments, all incoming ST2 genome segments are wild type, but the ST3 S4 genome segment possesses two mutations, G74 to A and G624 to A, that function as acceptance signals. Recognition of these signals has far-reaching implications for the construction of reoviruses with novel properties and functions.
Collapse
Affiliation(s)
- M R Roner
- Department of Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | | | | | | | | |
Collapse
|
15
|
|
16
|
Müller H, Lange H, Becht H. Formation, characterization and interfering capacity of a small plaque mutant and of incomplete virus particles of infectious bursal disease virus. Virus Res 1986; 4:297-309. [PMID: 3017017 DOI: 10.1016/0168-1702(86)90008-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Serial undiluted passages of infectious bursal disease virus in chick embryo cells were accompanied by a von Magnus type fluctuation of infectivity in viral harvests and a gradual decrease of plaque size. From the 9th undiluted passage on, the whole virus population consisted of small plaque-forming virus. The small plaque size remained constant when subsequent infections were carried out at low multiplicities. Small plaque virus interfered with the replication of large plaque standard virus. The small plaque/low yield mutation favoured the generation of defective particles which could be separated from complete particles by their lower densities in CsCl-gradients, where six fractions became visible and could be analyzed separately. Most of the defective virus particles had lost the larger of their two dsRNA segments and showed an aberrant protein composition. They had a very low residual infectivity and were also able to interfere with the replication of complete virus.
Collapse
|
17
|
Hundley F, Biryahwaho B, Gow M, Desselberger U. Genome rearrangements of bovine rotavirus after serial passage at high multiplicity of infection. Virology 1985; 143:88-103. [PMID: 2998015 DOI: 10.1016/0042-6822(85)90099-6] [Citation(s) in RCA: 93] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
After serial passage at high multiplicity of infection of standard bovine rotavirus in MA104 cells, different genome rearrangements occurred in which segment 5 was lost from the RNA profile and distinct additional bands of double-stranded (ds) RNA were found in positions on gels between segments 1 and 6. It was shown that some of the additional RNA bands contained segment 5-specific sequences. The additional RNA bands were transcribed in vitro to apparent full length. Analysis of the proteins synthesized in cells infected with viruses possessing rearranged genomes showed that in all cases the product of RNA segment 5, VP5, was missing; however, in one case an abnormal protein was observed which corresponded in size to the coding capacity of the mRNA transcribed from the additional genomic RNA band. Viruses with rearranged genomes could be plaque purified, and they grew in the absence of standard virus to titers comparable to those obtained from standard virus. In mixed infections of standard virus and virus possessing genome rearrangements, standard virus overgrew during passage at low multiplicity of infection whereas virus possessing genome rearrangements overgrew during passage at high multiplicity of infection.
Collapse
|
18
|
Barrett AD, Dimmock NJ. Differential effects of defective interfering Semliki Forest virus on cellular and virus polypeptide synthesis. Virology 1985; 142:59-67. [PMID: 4060572 DOI: 10.1016/0042-6822(85)90422-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Defective interfering Semliki Forest virus (DI SFV) inhibited virus RNA and virus polypeptide synthesis in cells coinfected with standard virus but did not delay or alter kinetics of RNA synthesis. Inhibition of polypeptide synthesis was 20-fold greater than that of RNA synthesis which presumably reflected the amplification resulting from cumulative translation of mRNAs. At high concentration, DI virus p12e inhibited the shutoff of host protein synthesis and allowed no synthesis of structural or nonstructural polypeptides. Dilution of DI virus restored the inhibition of host protein synthesis but further dilution was necessary before virus-specified polypeptide synthesis could be demonstrated. Another DI virus (p20a) with the same interference titre as p12e also inhibited shutoff of host protein synthesis but synthesis of virus-induced polypeptides was inhibited differentially: significant amounts of polypeptides comigrating with the structural precursor polypeptide p62 and the nonstructural polypeptide nsp63 were present and the synthesis of nsp90 was little affected at any concentration of DI virus p20a tested. None of the DI viruses tested induced the synthesis of any viral or novel polypeptide. It was concluded that DI SFV preparations have qualitatively different interfering activities in relation to their effects on virus and host cell polypeptide synthesis.
Collapse
|
19
|
|
20
|
Nuss DL, Summers D. Variant dsRNAs associated with transmission-defective isolates of wound tumor virus represent terminally conserved remnants of genome segments. Virology 1984; 133:276-88. [PMID: 6710865 DOI: 10.1016/0042-6822(84)90395-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Variant double-stranded RNAs are often associated with the genome of transmission-defective isolates of wound tumor virus. These RNAs are replicated and packaged into virus particles in systemically infected plants and are transcribed in vitro by the virion-associated transcriptase. Direct physical evidence that the variant RNAs are remnants of particular WTV genome segments was provided by molecular hybridization studies. Subsequently, ribonuclease T1 digestion products of 3'-end-labeled genome and remnant RNAs were analyzed by one- and two-dimensional electrophoretic techniques. One-dimensional partial and complete digestion patterns were indistinguishable, indicating that the guanosine positions relative to the 3' terminus of the corresponding strands of a particular genome segment and its remnant RNA are the same for at least 40 nucleotides from each end. Fingerprints of the 3' terminal ribonuclease T1-resistant fragments were identical, showing that the nucleotide composition of the 3' terminal ends of the corresponding strands of a particular genome segment and its remnant RNA are also identical. These results indicate that variant RNAs associated with transmission-defective WTV isolates are formed by deletion of an internal portion (as much as 85%) of genomic RNA segments yielding terminally conserved genomic remnants that are functional with respect to transcription, replication, and packaging.
Collapse
|
21
|
|
22
|
Abstract
Segmental genomes (i.e., genomes in which the genetic information is dispersed between two or more discrete molecules) are abundant in RNA viruses, but virtually absent in DNA viruses. It has been suggested that the division of information in RNA viruses expands the pool of variation available to natural selection by providing for the reassortment of modular RNAs from different genetic sources. This explanation is based on the apparent inability of related RNA molecules to undergo the kinds of physical recombination that generate variation among related DNA molecules. In this paper we propose a radically different hypothesis. Self-replicating RNA genomes have an error rate of about 10(-3) - 10(-4) substitutions per base per generation, whereas for DNA genomes the corresponding figure is 10(-9) - 10(-11). Thus the level of noise in the RNA copier process is five to eight orders of magnitude higher than that in the DNA process. Since a small module of information has a higher chance of passing undamaged through a noisy channel than does a large one, the division of RNA viral information among separate small units increases its overall chances of survival. The selective advantage of genome segmentation is most easily modelled for modular RNAs wrapped up in separate viral coats. If modular RNAs are brought together in a common viral coat, segmentation is advantageous only when interactions among the modular RNAs are selective enough to provide some degree of discrimination against miscopied sequences. This requirement is most clearly met by the reoviruses.
Collapse
|
23
|
Kauffman RS, Ahmed R, Fields BN. Selection of a mutant S1 gene during reovirus persistent infection of L cells: role in maintenance of the persistent state. Virology 1983; 131:79-87. [PMID: 6649416 DOI: 10.1016/0042-6822(83)90535-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
LR-7 cells, variant L cells derived from a type 3 reovirus persistently infected (p.i.) carrier culture (R. Ahmed, W. M. Canning, R. S. Kauffman, A. H. Sharpe, J. V. Hallum, and B. N. Fields, Cell 25, 325-332, 1983) were used to define the viral genes critical for maintenance of the persistent state. A cloned viral isolate (L/C virus) derived from the p.i. culture replicated normally in LR-7 cells, while wild-type (wt) viruses of the three reovirus serotypes replicated less efficiently. To identify the viral gene(s) permitting enhanced replication of L/C virus in LR-7 cells, viral reassortants were prepared by mixed infection of L cells with L/C virus and type 1 wt. Study of the one-step growth curves and final yields of large numbers of reassortants in both L cells and LR-7 cells revealed that the presence of the S1 gene from L/C virus was critical for normal viral replication in LR-7 cells. However, this phenotype was suppressed by the simultaneous presence in reassortants of both the M2 and S4 genes from the type 1 wt parent. The critical change in the S1 gene occurred by passage 13 (63 days) after initiation of the carrier culture. Although multiple mutations are present in the viral population from p.i. cultures, certain specific mutations can be identified as critical for maintenance of the persistent state.
Collapse
|
24
|
Ahmed R, Kauffman RS, Fields BN. Genetic variation during persistent reovirus infection: isolation of cold-sensitive and temperature-sensitive mutants from persistently infected L cells. Virology 1983; 131:71-8. [PMID: 6649415 DOI: 10.1016/0042-6822(83)90534-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
We have examined the evolution of reovirus in two independently established persistently infected (p.i.) cell lines. We found that reovirus undergoes extensive mutation during persistent infection in L cells. However, there was no consistent pattern of virus evolution; in one p.i. cell line temperature-sensitive (ts) mutants were selected, whereas cold-sensitive (cs) mutants were isolated from the second p.i. culture. Neither the cs nor the ts mutants isolated from the carrier cultures expressed their defect at 37 degrees, the temperature at which the p.i. cells were maintained, indicating that the cs and ts phenotypes were nonselected markers. These results emphasize the point that emergence of the ts or cs mutants during persistent infection only signifies that the virus has changed; it does not necessarily imply that the particular mutant is essential for the maintenance of the persistent infection. Given the high mutation rate of viruses, and the wide spectrum of viral mutants present in carrier cultures, it is essential to distinguish the relevant changes from those which may simply represent an epiphenomenon. In the accompanying paper (R. S. Kauffman, R. Ahmed, and B. N. Fields Virology, 130, 79-87, 1983), we show that by using a genetic approach, it is possible to identify the viral gene(s) which are critical for the maintenance of persistent reovirus infection.
Collapse
|
25
|
Lipson SM, Stotzky G. Adsorption of reovirus to clay minerals: effects of cation-exchange capacity, cation saturation, and surface area. Appl Environ Microbiol 1983; 46:673-82. [PMID: 6639022 PMCID: PMC239333 DOI: 10.1128/aem.46.3.673-682.1983] [Citation(s) in RCA: 101] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The adsorption of reovirus to clay minerals has been reported by several investigators, but the mechanisms defining this association have been studied only minimally. The purpose of this investigation was to elucidate the mechanisms involved with this interaction. More reovirus type 3 was adsorbed, in both distilled and synthetic estuarine water, by low concentrations of montmorillonite than by comparable concentrations of kaolinite containing a mixed complement of cations on the exchange complex. Adsorption to the clays was essentially immediate and was correlated with the cation-exchange capacity of the clays, indicating that adsorption was primarily to negatively charged sites on the clays. Adsorption was greater with low concentrations of clays in estuarine water than in distilled water, as the higher ionic strength of the estuarine water reduced the electrokinetic potential of both clay and virus particles. The addition of cations (as chloride salts) to distilled water enhanced adsorption, with divalent cations being more effective than monovalent cations and 10(-2) M resulting in more adsorption than 10(-3) M. Potassium ions suppressed reovirus adsorption to montmorillonite, probably by collapsing the clay lattices and preventing the expression of the interlayer-derived cation-exchange capacity. More virus was adsorbed by montmorillonite made homoionic to various mono-, di-, and trivalent cations (except by montmorillonite homoionic to potassium) than by comparable concentrations of kaolinite homoionic to the same cations. The sequence of the amount of adsorption to homoionic montmorillonite was Al greater than Ca greater than Mg greater than Na greater than K; the sequence of adsorption to kaolinite was Na greater than Al greater than Ca greater than Mg greater than K. The constant partition-type adsorption isotherms obtained when the clay concentration was maintained constant and the virus concentration was varied indicated that a fixed proportion of the added virus population was adsorbed, regardless of the concentration of infectious particles. A heterogeneity within the reovirus population was indicated.
Collapse
|
26
|
Ramig RF. Factors that affect genetic interaction during mixed infection with temperature-sensitive mutants of simian rotavirus SA11. Virology 1983; 127:91-9. [PMID: 6305020 DOI: 10.1016/0042-6822(83)90374-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A number of factors that affect genetic interaction during mixed infection with temperature-sensitive mutants of simian rotavirus SA11 have been examined. (1) Statistical analyses of recombination frequency (RF) indicated that (a) the variability noted in RF was not related to variations in experimental conditions and (b) a linear map of the mutations could not be drawn. (2) The wild phenotype of recombinant progeny was stable on passage. (3) Aggregates of progeny virus or heterozygous progeny virus particles did not contribute significantly to the observed RF. (4) RF increased in parallel with multiplicity of infection. (5) A maximal, or near maximal, RF was obtained at the earliest time significant recombinants could be detected. (6) Recombination was efficient at nonpermissive temperature. (7) Complementation did not occur or was inefficient. (8) Mutants from all recombination groups interfered with the growth of wild-type virus at both permissive and nonpermissive temperatures.
Collapse
|
27
|
Fields BN, Greene MI. Genetic and molecular mechanisms of viral pathogenesis: implications for prevention and treatment. Nature 1982; 300:19-23. [PMID: 6290894 DOI: 10.1038/300019a0] [Citation(s) in RCA: 107] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The pathogenesis of infection of mice by the mammalian reoviruses involves several discrete steps. Each of the three viral outer capsid proteins has a highly distinct and specialized role: one protein (sigma 1) binds to cell surface receptors; a second protein (mu 1C) determines the capacity for viral growth at mucosal surfaces; and the third protein (sigma 3) is responsible for inhibiting cell macromolecular synthesis. A detailed picture of the molecular basis of reovirus virulence and attention is now emerging.
Collapse
|
28
|
|
29
|
Ahmed R, Canning WM, Kauffman RS, Sharpe AH, Hallum JV, Fields BN. Role of the host cell in persistent viral infection: coevolution of L cells and reovoirus during persistent infection. Cell 1981; 25:325-32. [PMID: 7285112 DOI: 10.1016/0092-8674(81)90050-7] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Mutant L cells, designated LR cells, were isolated after "curing" a persistently infected cell line (L/C) with antireovirus serum. The LR cells were shown to be virus-free; no reovirus was detectable by infectious center assays, plaque assays, presence of viral proteins, presence of viral dsRNA and immunofluorescence studies. Persistent infections were readily established n LR cells following infection with either cloned, low passage wild-type reovirus or cloned, low passage reovirus isolated from carrier cultures. Reovirus isolated from carrier cultures, however, grew much better than wild-type reovirus in LR cells and showed complete dominance over wild-type reovirus in coinfection experiments. Infection of LR cells with wild-type reovirus resulted in a low-level persistent infection with inefficient viral replication; these mutant L cells were partially resistant to infection with wild-type reovirus. In contrast, infection of the mutant L cells with virus isolated from the persistently infected cells resulted in a persistent infection accompanied with efficient viral replication. Infection of the original L cells with either wild-type reovirus or reovirus isolated from the persistently infected cells resulted in a lytic infection with no surviving cells. Thus the host cell plays a crucial role in the maintenance of persistent reovirus infection. Our results show that there is a coevolution of both mutant L cells and mutant reovirus during persistent infection.
Collapse
|