Satellite (biology)

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Satellites are subviral particles made up of a nucleic acid molecule and some proteins. They can be viewed as dependent viruses that are unable to multiply in a host cell on their own. For their replication they also need one or even several helper viruses , with which the host cell must be infected at the same time ( co-infection ). The helper virus provides the functions required for the satellite to multiply. The host cell then mainly produces the satellite instead of the virus.

If the genome of the satellite codes for a nucleocapsid , it is called a satellite virus . As a rule, satellite viruses cannot replicate themselves. Virusoids, on the other hand, can replicate independently of the helper virus, but do not code for a capsid.

Diseases caused by satellites are known almost exclusively in plants (tobacco, tomatoes, cereals, gooseberries, etc.). Some have been found in fungi ( Ustilago maydis and Saccharomyces cerevisiae ) and protists ( Trichomonas vaginalis ). Chronic bee paralysis in bees is caused by satellites.

If the satellite interferes with or disturbs the replication of the helper virus ( ie if it parasitizes it), it is sometimes called a " virophage ".

Taxonomy

Satellites were taxonomically recorded with the ICTV update in November 2018 . In principle, the same scheme is used as for viruses, but with name endings that do not have “vir” but “satellite” as a component. In actual use at this stand, the following groups are:

Family ( ... satellitidae )
Subfamily ( ... satellitinae )
Genus or genus ( ... satellite )
Species or species ( ... satellite )

Example of such a satellite taxonomy :

Family: Alphasatellitidae
Subfamily: Geminialphasatellitinae
Genus: Ageyesisatellite
Type: Ageratum yellow vein Singapore alphasatellite

In practice, however, many satellite viruses use the common virus naming convention, e.g. B. for the genus Mavirus or the species Mimivirus-dependent virus Sputnik (both confirmed by ICTV).

Classification

Previously, they had been provisionally into different groups and subgroups classified :

Classification : satellites

  • Group: satellite nucleic acids
    • Type: Single-stranded Satellite RNAs
      • Subgroup: Circular Satellite RNAs
      • Subgroup: Small Linear Satellite RNAs
        • Pea enation mosaic virus ( Pea enation mosaic virus 1 , Luteoviridae : Enamovirus )
        • Cucumber mosaic virus ( Cucumber mosaic virus , Bromoviridae : Cucumovirus )
        • Cymbidium Ringspot Virus ( Tombusviridae : Tombus virus )
        • Peanut rosette virus ( Groundnut rosette virus : Tombusviridae : Umbravirus )
        • Small gooseberry rosette virus
        • Peanut Stunt Virus ( Bromoviridae : Cucumovirus )
        • Turnip Crinkle Virus ( Tombusviridae : Betacarmovirus )
        • Tobacco necrosis virus ( Tobacco necrosis virus A , Tombusviridae : Alphanecrovirus )
        • Robinia Mosaic Virus (RoMV)
      • Subgroup: Large Satellite RNAs
        • Beet Necrotic Yellow Vein Virus satellite-like RNA
        • Great cruciferous mosaic virus
        • Bamboo mosaic virus ( Tymovirales : Alphaflexiviridae : Potexvirus )
        • (Large) Chicory Yellow Mottle Virus ( Secoviridae : Comovirinae : Nepovirus )
        • Grapevine Bulgarian Latent Virus (ditto)
        • Grapevine Fanleaf Virus (ditto, see brushwood disease )
        • Myrobalan Latent Ringspot Virus (ditto)
        • Tomato Blackring Virus (ditto)
        • Beet Ringspot Virus (ditto)
        • Strawberry Latent Ringspot Virus ( Secoviridae : genus not determined, see brushwood disease )
    • Type: Two-stranded satellite RNAs
        • Saccharomyces cerevisiae M virus satellite
        • Trichomonas vaginalis TI virus satellite
        • Ustilago Maydis Killer M Virus satellite
    • Type: Single-stranded satellite DNAs
  • Group: Satellite Viruses
    • Type: Single-stranded RNA satellite viruses

See also

swell

  • Principles of Virology: Molecular Biology, Pathogenesis and Control of Animal Viruses / SJ Flint [et al.] 2nd ed. ISBN 1-55581-259-7
  • Gerhard Drews, Günter Adam, Cornelia Heinze: Molecular Plant Virology, Springer-Verlag Berlin Heidelberg 2004, ISBN 3-540-00661-3 , pages 92f and 230ff.

Individual evidence

  1. ↑ Abbreviations can start with “S” and end with “V” (possibly followed by a number - not Roman, but Arabic).
  2. ↑ International Committee on Taxonomy of Viruses, Virus Taxonomy: 2018 Release
  3. ^ Tobacco necrosis satellite virus . In: NCBI Taxonomy Browser . 12881.