Macronovirus is the only genus of the family Sarthroviridae. It contains one species: Extra small virus (XSV, Macronovirus macrobrachii).[2]

It is found in The French West Indies, Thailand, Taiwan, China, and India.[3]

Etymology

The genus name, Macronovirus, is a combination of Macro, from the host Macrobrachium rosenbergii and no, from helper virus nodavirus.[3]

The family name, Sarthroviridae, is a combination of S, from Small and arthro, from host arthropoda.[4]

Hosts

Macronovirus's cell tropism is muscle and connective cells of diseased animals, and its natural hosts are arthropods.[4]

Structure

The virion of XSV has a genome consisting of linear single-stranded RNA of positive polarity, 0.8kb in size, with two genes. This encodes two capsid proteins, CP-17 and CP-16. The virion is non-enveloped, spherical, with a capsid of about 15 nm with icosahedral symmetry. The virion is constructed from two capsid proteins CP-17 and CP-16. It has a Monopartite, linear, ssRNA(+) genome.[3]

Gene expression

The virion RNA is infectious and serves as both the genome and viral messenger RNA.[3]

Replication

Its replication is cytoplasmic, and has 8 steps.[3]

  1. Attachement to host receptors mediates entry into the host cell.
  2. Uncoating, and release of the viral genomic RNA into the cytoplasm.
  3. Viral RNA is translated in a polyprotein to produce replication proteins.
  4. Replication by helper virus occurs in viral factories made of membrane vesicles derived from the ER. A dsRNA genome is synthesized from the genomic ssRNA(+).
  5. The dsRNA genome is transcribed/replicated thereby providing viral mRNAs/new ssRNA(+) genomes.
  6. Expression of the capsid proteins.
  7. Assembly of new virus particles.
  8. Virus release.

Disease

Whitish muscle disease, which develops in post-larvae of freshwater prawn Macrobrachium rosenbergii and is caused by Macrobrachium rosenbergii nodavirus (MrNV) and its associate Extra small virus. Main symptom is a whitish appearance of the muscles, particularly noticeable in the abdomen. Mortalities can reach 100%.[3]

References

  1. ^ "History of the taxon: Species: Macronovirus macrobrachii (2024 Release, MSL #40)". International Committee on Taxonomy of Viruses. Retrieved 22 March 2025.
  2. ^ "Virus Taxonomy: 2024 Release". International Committee on Taxonomy of Viruses. Retrieved 22 March 2025.
  3. ^ a b c d e f "Macronovirus ~ ViralZone report". ViralZone. Retrieved 12 August 2023. This article incorporates text from this source, which is available under the CC BY 4.0 license.
  4. ^ a b "Sarthroviridae ~ ViralZone report". ViralZone. Retrieved 12 August 2023. This article incorporates text from this source, which is available under the CC BY 4.0 license.
Allikas: https://en.wikipedia.org/wiki/Macrobrachium_satellite_virus_1
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