Positive-strand RNA virus

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Positive-sense ssRNA virus
)

Positive-strand RNA virus
Hepatitis C virus
Virus classification
Group:
Group IV (
(+)ssRNA
)
Kingdom: Phylum: Class
Synonyms
  • Positive-sense RNA virus

Positive-strand RNA viruses (+ssRNA viruses) are a group of related

host cell's ribosomes. Positive-strand RNA viruses encode an RNA-dependent RNA polymerase
(RdRp) which is used during replication of the genome to synthesize a negative-sense antigenome that is then used as a template to create a new positive-sense viral genome.

Positive-strand RNA viruses are divided between the phyla Kitrinoviricota, Lenarviricota, and Pisuviricota (specifically classes Pisoniviricetes and Stelpavirictes) all of which are in the kingdom Orthornavirae and realm Riboviria.[1] They are monophyletic and descended from a common RNA virus ancestor. In the Baltimore classification system, +ssRNA viruses belong to Group IV.[2]

Positive-sense RNA viruses include

SARS, and SARS-CoV-2 coronaviruses,[3] as well as less clinically serious pathogens such as the coronaviruses and rhinoviruses that cause the common cold.[4][5][6]

Genome

Positive-strand RNA virus genomes usually contain relatively few genes, usually between three and ten, including an RNA-dependent RNA polymerase.

nonstructural protein nsp14.[7]

Replication

membrane fusion, uncoating, translation, RNA replication, assembly, maturation, and release
.

Positive-strand RNA viruses have genetic material that can function both as a

plasma membranes, autophagosomal membranes, and novel cytoplasmic compartments.[4]

The replication of the positive-sense RNA genome proceeds through

affinity for ribosomes by the viral genome's internal ribosome entry site (IRES) elements; in some viruses, such as poliovirus and rhinoviruses, normal protein synthesis is further disrupted by viral proteases degrading components required to initiate translation of cellular mRNA.[6]

All positive-strand RNA virus genomes encode

secretory pathway for viral replication.[4]

Recombination

Mechanisms of replicative and nonreplicative RNA recombination.

Numerous positive-strand RNA viruses can undergo

SARS).[14] Recombination in RNA viruses appears to be an adaptation for coping with genome damage.[9] Recombination can also occur infrequently between +ssRNA viruses of the same species but of divergent lineages. The resulting recombinant viruses may sometimes cause an outbreak of infection in humans, as in the case of SARS and MERS.[14]

Positive-strand RNA viruses are common in plants. In tombusviruses and carmoviruses, RNA recombination occurs frequently during replication.[15] The ability of the RNA-dependent RNA polymerase of these viruses to switch RNA templates suggests a copy choice model of RNA recombination that may be an adaptive mechanism for coping with damage in the viral genome.[15] Other +ssRNA viruses of plants have also been reported to be capable of recombination, such as Brom mosaic bromovirus[16] and Sindbis virus.[17]

Classification

Negarnaviricota (brown), Duplornaviricota (green), Kitrinoviricota (pink), Pisuviricota (blue), and Lenarviricota
(yellow).

Positive-strand RNA viruses are found in three phyla: Kitrinoviricota, Lenarviricota, and Pisuviricota, each of which are assigned to the kingdom Orthornavirae in the realm Riboviria. In the Baltimore classification system, which groups viruses together based on their manner of mRNA synthesis, +ssRNA viruses are group IV.[citation needed]

Kitrinoviricota

The first +ssRNA phylum is

Tolucaviricetes, which primarily contains plant viruses.[18][19]

Lenarviricota

mitoviruses and their relatives, and Miaviricetes, which contains botourmiaviruses and their relatives. Based on phylogenetic analysis of RdRp, all other RNA viruses are considered to comprise a sister clade in relation to Lenarviricota.[18][19]

Pisuviricota

virion. Coronaviruses like SARS-CoV-2 fall in the phylum Pisuviricota
.

The third phylum that contains +ssRNA viruses is

Duplopiviricetes, whose members are double-stranded RNA viruses that are descended from +ssRNA viruses.[18][19]

See also

References

  1. ^ "Current ICTV Taxonomy Release | ICTV". ictv.global. Retrieved 3 April 2023.
  2. PMID 4329869
    .
  3. PMID 32007145
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  4. ^
    PMID 22183253
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  5. PMID 12857886
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  6. ^
    S2CID 82608215
    .
  7. PMID 24348241
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  8. ^ a b "Positive stranded RNA virus replication". ViralZone. Retrieved 8 September 2016.
  9. ^
    PMID 20335491
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  10. PMID 31540135
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  11. PMID 1700865
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  12. PMID 30307534
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  13. PMID 29111273
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  14. ^
    PMID 27012512
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  15. ^
    PMID 14581540
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  16. PMID 27774290
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  17. PMID 2072444
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  18. ^ a b c Koonin EV, Dolja VV, Krupovic M, Varsani A, Wolf YI, Yutin N, Zerbini M, Kuhn JH (18 October 2019). "Create a megataxonomic framework, filling all principal taxonomic ranks, for realm Riboviria" (docx). International Committee on Taxonomy of Viruses (ICTV). Retrieved 14 August 2020.
  19. ^
    PMID 30482837
    .
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