Reoviridae

The Reoviridae form the largest family of non-enveloped viruses with double-stranded RNA (dsRNA ). Together with the Birnaviridae Partitiviridae and they are the only viruses whose genome is present segmented dsRNA. This family includes such important pathogens such as bluetongue virus, the human rotaviruses or the Colorado tick fever virus. The name of the family is an acronym of "respiratory, enteric, orphan", as it was felt that members of this taxonomic group, only bowel disease (enteric ), respiratory disease ( respiratory ) or no disease ( orphan ) would cause. Reoviridae actually been found in many mammals, as well as reptiles, fish, crustaceans, and insects. Three genera of the family ( Fijivirus, Phytoreovirus and Oryzavirus ) include pathogens in plants ( plant viruses ) and fungi ( Mykoviren ).

Morphology

The mature virions are nonenveloped Reoviridae, ikosadrische capsids with a diameter of about 60-80 nm characteristic of most genera of the family ( with the exception of the genus Cypovirus ) is the structure of the virion from two nested and closely interacting capsids (T = 13), which in turn surrounded an inner core regular structure. Therefore constructed as three layers of proteins virions in the electron microscope show a very typical, thick-walled structure with regular, spoke-like thickenings. Derived from these spokes structure received the genus Rotavirus (Latin rota: Rad ) its name. This structure is formed by the spoke openings 132 of the outer capsid, which open into the same number of channels of the inner capsid. These channels, which extend up to the inner core, allow diffusion of ions into the virion. Characterized in that the inner core and the inner capsid responsible for the correct packaging of the RNA segments, the outer capsid, a relatively large variation of the surface structures have without the stability of the virion and affect the integrity of the genome. Therefore, show many reoviruses numerous species and serotypes. In the inner core shell is a molecule of the viral RNA polymerase and guanyltransferase. In some genera myristyl radicals ( tetradecyl groups) are covalently bound to the capsid. In the genera Rotavirus, orbivirus and Coltivirus immature virions are found to possess the remains of a lipid envelope. These genera leaving the cell by budding of the cell membrane ( orbivirus, Coltivirus ) or of the membrane of the endoplasmic reticulum (ER) occurs ( rotavirus ). By an enzymatic maturation step, the virions lose the lipid envelope again. In some genera the outer capsid by host-specific proteases (eg, trypsin, chymotrypsin ) is changed, whereby so-called " infectious subviral particles" ( ISVPs ) arise. Only the ISVPs are infectious and the transition from immature virions to ISVPs plays a crucial role in the pathogenesis and the different appearance of the virions in the gut, saliva or blood serum of these viruses.

Genome

The genome consists of a double-stranded RNA that is divided according to type in 10 to 12 segments. The molecular weight of the segments ranges from 0.2 to 3 x 106 Da. The viral mRNA Reoviridae does not have a poly -A tail. Some virus species is found short, single-stranded RNA oligonucleotides in the inner core shell.

System

  • Family Reoviridae genus Orthoreovirus
  • Genus orbivirus
  • Genus rotavirus
  • Genus Coltivirus
  • Genus Aquareovirus
  • Genus Cypovirus
  • Genus Fijivirus
  • Genus Phytoreovirus
  • Genus Oryzavirus
  • Genus Seadornavirus
  • Genus Idnoreovirus
  • Genus Mycoreovirus

Non - classified virus species within the family Reoviridae:

  • Species Buthus - occitanus reovirus ( BoRV ) with scorpions Buthidae family
  • Species Cimex lectularis reovirus ( CLRV ) at the bedbug Cimex lectularius
  • Species Carcinus mediterraneus -W2 virus ( CcRV -W2 ) in decapods ( Decapoda )
  • Species Macropipus - depurator -P virus ( DPPV, MDRV -P) ( Decapoda )
  • Species Porcelio - dilatatus reovirus ( Pdrv ) in isopods ( Isopoda )
  • Species Scylla serrata reovirus SZ- 2007 swimming crabs of the genus Scylla
  • Species Eriocheir sinensis reovirus in the Chinese mitten crab
  • Species Operophtera - brumata reovirus at little winter moth

Swell

  • PPC Mertens, C. Wei, B. Hillmann: Family Reoviridae. In: C. M. Fauquet, M. A. Mayo et al.: Eighth Report of the International Committee on Taxonomy of Viruses, London, San Diego, 2004, pp. 447-555
  • S. Mordrow, D. Falke, U. Truyen: Molecular Virology, Heidelberg Berlin, 2nd edition 2003 ISBN 3-8274-1086- X
Virus classification National Center for Biotechnology Information Mycovirus Virus#Etymology RNA-Polymerase Intestine Serum (blood)
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