Reovirus

8 Key excerpts on "Reovirus"

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  eBook - ePub

  Diseases of Poultry

  • (Author)
  • 2013(Publication Date)
  • Wiley-Blackwell

    (Publisher)

  Chapter 11 Reovirus Infections Richard C. Jones Introduction Avian Reoviruses are members of the OrthoReovirus genus, one of 12 genera of the Reoviridae family. In turn they are assigned the species Spinareovirinae, one of the five recognized species of the genus OrthoReovirus, which also contains the non-fusogenic mammalian Reoviruses, the two fusogenic mammalian Reoviruses Nelson Bay virus (bat) and baboon Reovirus, as well as fusogenic Reoviruses isolated from reptilian species. Avian and mammalian Reoviruses are the two principal groups of the genus and while they share many biological characteristics, they differ in host range, pathogenicity, coding capacity, and other biological properties (3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 16). Unlike their mammalian counterparts, the avian Reoviruses cause fusion of host cells (see Diagnosis) but lack hemagglutinating activity. Avian Reovirus structure and biology have been reviewed in detail by Benavente and Martinez-Costas (1). The double-stranded RNA (dsRNA) genome consisting of 10 segments packaged into a non-enveloped icosahedral double-shelled capsid of approximately 80 nm diameter (Figure 11.1). The name “Reovirus” derives from “respiratory, enteric orphan,” because they were first isolated from these sites in humans with initially no apparent association with disease

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  Fundamentals of Molecular Virology

  • Nicholas H. Acheson(Author)
  • 2012(Publication Date)
  • Wiley

    (Publisher)

  225 Reoviridae From respiratory enteric orphan viruses VIRION Naked icosahedral capsid (T  13), Diameter 60–85 nm. Capsid consists of two or three concentric protein shells. Inner capsid (T  1), or core, contains RNA polymerase and capping enzymes. GENOME Linear double-stranded RNA, 10–12 segments. Total genome length 18–24 kb. GENES AND PROTEINS mRNAs are full-length copies of each genome segment. Typically one protein is encoded per genome segment. 6–8 capsid proteins. 3–6 nonstructural proteins. VIRUSES AND HOSTS 12 genera, including OrthoReovirus, Rotavirus, Orbivirus. Infect humans (Reoviruses types 1–3, rotaviruses, and Colorado tick fever virus), mammals, birds, fish, mollusks, plants, insects, and fungi. DISEASES Members of genus OrthoReovirus cause little or no disease in humans. Rotavirus is an important cause of gastroenteritis worldwide and infant mortality in the developing world. Viruses spread between hosts by direct transmis- sion, contaminated food or water, or arthropod vectors. DISTINCTIVE CHARACTERISTICS Reovirus family has members that infect a broad range of hosts from fungi to humans. mRNAs are synthesized and capped inside intact cores and extruded through channels into the cytosol. Synthesis of double-stranded genome RNAs occurs within core-like subvirion particles. A single copy of each gene segment is packaged into each virion by an unknown sorting mechanism. Gene segments can be reassorted during coinfection of cells by different strains. C H A P T E R 1 9 Reoviruses James D. Chappell Terence S. Dermody Reoviruses were the first double-stranded RNA viruses discovered Reoviruses were first isolated from stool specimens of children during the 1950s by Albert Sabin, Leon Rosen, and their colleagues.

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  eBook - ePub

  Virology

  • Maria Carla Saleh, Felix Augusto Rey(Authors)
  • 2021(Publication Date)
  • Wiley-ISTE

    (Publisher)

  et al. 2014); however, because the genome remains packaged within the core of incoming viral particles, it is not clear if the genome segments are exposed during the viral replication cycle. Instead, it is possible that the host recognizes extensively folded or incompletely capped viral (+)ssRNAs. Host recognition of viral infection via dsRNA sensors typically leads to activation of the type I interferon (IFN) response, which leads to the production of antiviral IFN-stimulated genes that inhibit viral replication.

  Reovirus represses the type I IFN response in a strain-specific manner via the μ2 protein, which causes a nuclear accumulation of IFN regulatory factor 9 (IRF9) and thus prevents IFN signaling (Zurney et al. 2009). In infected cells, μ2 predominantly localizes to viral factories, but it has also been shown to localize to the nucleus (Mbisa et al. 2000; Parker et al. 2002; Kobayashi et al. 2009). The type I Lang (T1L) strain of Reovirus, but not the type 3 Dearing strain, encodes a μ2 that complexes with the pre-mRNA splicing factor SRSF2 in nuclear speckles (Rivera-Serrano et al. 2017). The interaction of μ2 with SRSF2 results in alteration of transcript splicing for genes involved in RNA processing and maturation. Several lines of evidence indicate that the Reovirus σ3 protein also blocks the IFN response during infection. In other viral systems, σ3 can substitute for PKR repressors or analogous dsRNA-binding proteins (Beattie et al. 1995; Gainey et al. 2008). However, activation of PKR does not appear to inhibit Reovirus replication, and Reovirus may benefit from the activation of PKR (Smith et al. 2005; Zhang and Samuel 2007).

  2.4. Orbiviruses

  Orbiviruses are arthropod-borne viruses that comprise the Orbivirus genus of the family Reoviridae. Orbiviruses can cause non-contagious infectious disease in vertebrates, arthropods and plants. The most important pathogenic orbiviruses are bluetongue virus (BTV) and African horsesickness virus (AHSV). Both bluetongue (BT) and African horsesickness (AHS) are OIE-listed3 diseases that are subject to strict control with regard to international trade and movement of animals. Certain biting hematophagous midge vectors of the genus Culicoides (Diptera: Ceratopogonidae) are the biological vectors transmitting BTV and AHSV between their hosts (Du Toit 1944; Roy 2013). There are 27 serotypes of BTV (Schulz et al

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  Comparative Diagnosis of Viral Diseases

  Vertebrate Animal and Related Viruses Part B—DNA Viruses

  • Edouard Kurstak(Author)
  • 2012(Publication Date)
  • Academic Press

    (Publisher)

  t Since completing this chapter, it has come to my attention that this virus will be excluded from the Reoviridae and probably placed in a new family (F. A. Murphy, personal communication, 1979). 2. Orbivirus and Reovirus Infections 99 within the Reoviridae. Unfortunately they have been insufficiently characterized for useful comment and will not be discussed in this chapter. Readers are referred to Andrewes et al. (1978) for further information. V. CONCLUSION The Reoviridae comprise five genera: Reovirus, Orbivirus, Rotavirus, PhytoReovirus, and Fijivirus, plus the cytoplasmic polyhedrosis viruses. All share common properties but may be clearly differentiated and characterized. Orbiviruses are arthropod-transmitted and Reoviruses are not. Only a few of the orbiviruses produce diseases in mammals, but those disease are of serious eco-nomic consequence. Characterization within the genera Reovirus and Orbivirus has been outlined from the results of serological tests such as CF, HI, neturaliza-tion, immunofluorescence, immunoperoxidase, gel diffusion, and radioim-munoassay, as well as from morphological, ecological, and epizootiological information. These tests are inadequate for the taxonomic characterization of the large numbers of isolates now accumulating. The viral genome, consisting of 10 segments of double-stranded RNA, facilitates genetic reassortment. This ex-change of genetic information probably relates to the evolution of many closely related orbiviruses. It is suggested that analysis of the double-stranded RNA genome through techniques such as PAGE is required if effective progress on characterization is to be made. Although the numerous names are delightful and of geographic interest, it is suggested that the Gorman grouping be adopted for orbiviruses and that a similar approach be used for Reoviruses and other genera of the Reoviridae.

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  eBook - ePub

  Plant Viruses

  Volume I: Structure and Replication

  • C.L. Mandahar(Author)
  • 2018(Publication Date)
  • CRC Press

    (Publisher)

  Chapter 6 Plant Reoviruses

  E. Shikata

  Table of Contents

  I. Introduction

  II. Structure

  A. Virion

  1. Shape and Structure

  a. PhytoReovirus

  b. Fijivirus

  c. Rice Ragged Stunt Virus (RRSV)

  2. Various Physical and Hydrodynamic Constants

  a. Sedimentation Coefficient

  b. Molecular Weight

  c. Buoyant Density

  B. Capsid

  1. Detailed Architecture

  a. PhytoReovirus

  b. Fijivirus

  c. Rice Ragged Stunt Virus

  2. Structural Proteins/Protein Subunits

  a. PhytoReovirus

  b. Fijivirus

  c. Rice Ragged Stunt Virus

  3. Empty Protein Shells

  C. Nucleic Acid/Genome

  1. Type and Structure

  a. PhytoReovirus

  b. Fijivirus

  c. Rice Ragged Stunt Virus

  2. Structure of the 5′ Termini, Genome-Linked Protein

  a. PhytoReovirus

  3. Structure of the 3′ Termini

  4. Physical and Hydrodynamic Constants

  5. Genetic Map

  a. Transcription and Translation

  6. Antigenecity

  D. Structural Characteristics of Plant Reoviruses

  III. Replication

  References

  I. Introduction

  Among the plant viruses there are only two groups that share families with verterbrate and invertebrate viruses. They are Reoviridae and Rhabdoviridae. Both are insect-borne plant-pathogenic viruses transmitted in a persistent manner. Some of the plant viruses belonging to Reoviridae have been extensively studied for biological relationship between the insect vectors and the viruses. Fukushi's finding1 , 2 , 3 on transovarial passage of rice dwarf virus (RDV) into insect progeny and on propagative transmission of the virus in the leafhopper vectors attracted attention on the relationship between plant viruses and insect vectors. Although the studies on wound tumor virus (WTV) supported his finding,4 it took a long time to reach complete agreement on the propagative transmission of leafhopper-borne plant viruses — direct evidence of viral multiplication in insect vectors was needed. The first approach was made by an artificial injection technique;5 the second was purification of the viruses from plant and insect hosts;6 , 7 and the third was electron microscopic studies of both hosts.8 , 9 , 10

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  eBook - PDF

  Animal Virus Structure

  • M.V. Nermut, A.C. Steven(Authors)
  • 1987(Publication Date)
  • Elsevier Science

    (Publisher)

  PART IV RNA-containing virus families This Page Intentionally Left Blank Nermut/Stevea (eds) Animal Virus Structure 0 1987 Elsevier Science Publishers B.V. (Biomedical Division) 107 CHAPTER 6 Picornaviridae P.MINOR National lnsrirute for Biological Standards and Conrrol, Blanche Lane, South Mirnrns, Potters Bar, Herts EN6 3QG. U. K. Family: Picornaviridae Genera: enterovirus, cardiovirus, rhinovirus, aphthovirus 6.1. General characteristics Picornaviruses are small non-enveloped viruses with an icosahedral shell enclosing an RNA genome. They replicate in the cytoplasm of infected cells, and cause a variety of diseases of man and animals, involving a range of specific target organs and tissues depending on the particular virus. No vectors are known. Picornaviruses can be broadly classified into four categories: the enteroviruses (encompassing polioviruses, coxsackie viruses, echoviruses, numbered enterovi- ruses and possibly hepatitis A virus), the aphthoviruses of foot-and-mouth disease viruses, the rhinoviruses and the cardioviruses (including mengovirus and encephalomyocarditis virus). The biophysical and molecular biological properties of all picornaviruses are broadly similar, but the categories differ in details such as the stability of the virion to various treatments, and certain features of the molecular organization of the genomes. Recently the X-ray crystallographic structure of a rhinovirus has been reported, as has that .of a poliovirus, and it is likely that by the time of going to press the structure of a cardiovirus (mengovirus) will also have been resolved and that of foot-and-mouth disease virus will be the subject of study. Detailed structural in- formation is thus rapidly becoming available on the picornaviridae. 108 6.2. Enteroviruses: species poliovirus 6.2.1. CHEMICAL AND PHYSICAL CHARACTERISTICS The virus particle has a mass of approximately 8 x lo6 daltons, of which the RNA genome contributes 2.6 x lo6 daltons (32%).

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  Viruses and Human Disease

  • Ellen G. Strauss, James H. Strauss(Authors)
  • 2002(Publication Date)
  • Academic Press

    (Publisher)

  In general, the avian viruses do not grow in mammalian cells or must be adapted to mammalian cells before they will grow, and thus have a host range distinct from that of the mammalian viruses. The relationships among these viruses are illustrated by the tree in Fig. 3.39. Notice that the three mammalian viruses group closely together and are distinct from the other Reoviruses, including the baboon virus. Reovirus serotype 3 has been extensively studied as a model for the members of the orthoReovirus genus. In the following discussion, in which aspects of the genome orga-nization, replication, and structure of orthoReoviruses are described, specific details refer to Reovirus ST3. These details are summarized in Table 3.16. The Genome of OrthoReoviruses The genomes of orthoReoviruses consist of 10 segments of dsRNA (Fig. 3.40). The genome segments range in size from 3.9 to 1.2 kb and sum to 23.5 kb for Reovirus ST3 (Table 3.16). Twelve proteins are produced of which eight are components of the virion, four in the outer shell and four in the inner shell. 112 Plus-Strand and Double-Strand RNA Viruses Lane 1 2 3 Large (L) Segments Medium (M) Segments Small (S) Segments FIGURE 3.40 Gel electrophoresis of the orthoReovirus RNA genome segments, showing the variation of the segment size with serotype. Lane 1, Reovirus serotype 2 (Jones); lane 2, Reovirus serotype 1 (Lang); lane 3, serotype 3 (Deering). The segments cluster into three groups: 3L (large), 3M (medium), and 4S (small). [From Fields et al . (1996, p. 1559).] Entry of OrthoReoviruses into the Cell After attachment to receptors, orthoReoviruses are inter-nalized into endosomes. In endosomes or in lysosomes, proteolysis of two proteins in the outer shell, 3 and 1C, produces what has been termed an ISVP (infectious subvi-ral particle or intermediate subviral particle). In this process, 1C is cleaved to produce two fragments, and a small C terminal , whereas 3 is degraded.

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  Taxonomic Guide to Infectious Diseases

  Understanding the Biologic Classes of Pathogenic Organisms

  • Jules J. Berman(Author)
  • 2019(Publication Date)
  • Academic Press

    (Publisher)

  Though we cannot as yet classify viruses strictly by their evolutionary lineage, we can usefully group viruses based on the physical characteristics of their genomes. The Baltimore Classification divides viruses into seven groups based on whether their genome is DNA, RNA, single stranded, or double stranded, the sense of the single strand, and the presence or absence of a reverse transcriptase. Here are the classes of the pathogenic viruses. This classification, though nonphylogenetic in concept, has the great advantage of being comprehensive: every known virus can be assigned to a group within the Baltimore Classification.

  Group I, double-stranded DNA Group II, single-stranded DNA Group III, double-stranded RNA Group IV, positive sense single-stranded RNA Group V, negative sense single-stranded RNA ssRNA Group VI, single-stranded RNA with a reverse transcriptase Group VII, double-stranded DNA with a reverse transcriptase

  It is worth repeating that when we use the Baltimore Classification (or any alternate viral classification, for that matter) we must grudgingly accept the fact that biologically relevant features of grouped viruses will cross taxonomic boundaries. Consider the arboviruses. Arbovirus is a shortened name for Arthropod borne virus. The arboviruses fall into several different groups of viruses. The principle vectors of the arboviruses are mosquitoes, ticks. Mosquito-borne arboviruses are members of Class Bunyaviridae (Group V), Flaviviridae (Group IV), or Togaviridae (Group IV). Tick-borne arboviruses are members of Class Bunyarviridae (Group V), Flaviviridae (Group IV), or Reoviridae (Group III). Over 500 arboviruses, infecting a variety of animals, have been described [47] . The arboviruses, organized by their transmission vectors, as shown below, cross multiple viral groups.

  Mosquito-borne viruses. Bunyaviridae (Group V) La Crosse encephalitis virus California encephalitis virus Rift Valley fever virus Flaviviridae (Group IV) Japanese encephalitis virus Australian encephalitis virus St. Louis encephalitis virus West Nile fever virus Dengue fever virus Yellow fever virus Zika fever virus Togaviridae (Group IV) Eastern equine encephalomyelitis virus Western equine encephalomyelitis virus Venezuelan equine encephalomyelitis virus Chikungunya virus O'Nyong-nyong fever virus Ross River fever virus Barmah Forest virus

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