Faustovirus

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Faustovirus
Faustovirus.png
Cryo electron microscopy reconstruction of Faustovirus, from EMD-8144 [1]
Virus classification
Group:
Group I (dsDNA)
Family:
Asfarviridae
Genus:
Faustovirus
Negative staining of "Faustovirus ST1" purified suspension showing an icosahedral particle of 200 nm. Scale bar 100 nm. Viruses-11-00312-g004 Faustovirus ST1.png
Negative staining of "Faustovirus ST1" purified suspension showing an icosahedral particle of 200 nm. Scale bar 100 nm.

Faustovirus is a genus of giant virus which infects amoebae associated with humans. The virus was first isolated in 2015 [2] and shown to be around 0.2 micrometers in diameter with a double stranded DNA genome of 466 kilobases predicted to encode 451 proteins. Although classified as a nucleocytoplasmic large DNA virus (NCLDV), faustoviruses share less than a quarter of their genes with other NCLDVs; however, ~46% are homologous to bacterial genes and the remainder are orphan genes (ORFans). [3] Specifically, the gene encoding the major capsid protein (MCP) of faustovirus is different than that of its most closely related giant virus, asfivirus, as well as other NCLDVs. In asfivirus, the gene encoding MCP is a single genomic fragment of ~2000 base pairs (bp), [1] however, in faustovirus the MCP is encoded by 13 exons separated by 12 large introns. [4] The exons have a mean length of 149 bp and the introns have a mean length of 1,273 bp. [4] The presence of introns in faustovirus genes is highly unusual for viruses. [1]

Contents

Replication

The replication strategy of faustovirus in amoeba is similar to that of mimivirus. Lasting 18 to 20 hours, the replication cycle begins with the amoeba ingesting individual viral particles through a process known as phagocytosis. After about 2 to 4 hours post infection, virus particles are internalized via phagocytic vacuoles and are detected by the host. While the particles appear near the host's nucleus, there is no evidence that the virus is within the nucleus or has an interaction with the nuclear membrane. [2] Similar to the mimivirus, in which a channel is created for particle proteins and DNA to travel through, the faustovirus particles empty their internal compartments into the amoeba's cytoplasm. In both viruses, the fusion leads to an eclipse phase in which the contents of particles become invisible inside the cytoplasm of the host. However, the eclipse phase of the faustovirus is longer than the mimivirus, taking place from 4 to 6 hours post infection. [2] Characterized by a loss of its spherical shape and a decrease in surface area, the amoeba host cell undergoes reorganization, such that at 8 to 10 hours post infection there are new particles in a region forming a donut shape. This region is the viral factory; it is distinct from the nucleus and is surrounded by mitochondria. Between 12- and 18-hours post infection, the virus factory takes up the entirety of the cytoplasm, which is completely filled with new viral particles. At 18- to 20-hours post infection, the viral particles are released through cell lysis. [2]

Pathogenicity

Faustovirus affects amoeba associated with the human environment, like Vermamoeba vermiformis; this particular amoeba has been found in hospital water networks, drinking water, human stool samples, and contact lenses of keratitis patients, thus it may be a possible carrying agent for viruses. [5] Faustoviruses have been found in sewage water from various geographical locations, such as Senegal, France, Lebanon, and Saudi Arabia. [2] [6] Isolated strains of the virus have been detected in rodents, cattle, febrile and healthy humans, and well water and rivers. Although faustovirus was found in humans, it is unknown whether it has a pathogenic effect on humans; more research is required to determine the mode of infection and consequences of infection, if any exist. [6]

Related Research Articles

<i>Mimivirus</i> Genus of viruses

Mimivirus is a genus of giant viruses, in the family Mimiviridae. Amoeba serve as their natural hosts. This genus contains a single identified species named Acanthamoeba polyphaga mimivirus (APMV). It also refers to a group of phylogenetically related large viruses.

<span class="mw-page-title-main">Mobilome</span>

The mobilome is the entire set of mobile genetic elements in a genome. Mobilomes are found in eukaryotes, prokaryotes, and viruses. The compositions of mobilomes differ among lineages of life, with transposable elements being the major mobile elements in eukaryotes, and plasmids and prophages being the major types in prokaryotes. Virophages contribute to the viral mobilome.

<i>Asfarviridae</i> Family of viruses

Asfarviridae is a family of viruses, the best-studied of which is African swine fever virus. They are double-stranded DNA viruses.

<span class="mw-page-title-main">Virophage</span> Viral parasites of giant viruses

Virophages are small, double-stranded DNA viral phages that require the co-infection of another virus. The co-infecting viruses are typically giant viruses. Virophages rely on the viral replication factory of the co-infecting giant virus for their own replication. One of the characteristics of virophages is that they have a parasitic relationship with the co-infecting virus. Their dependence upon the giant virus for replication often results in the deactivation of the giant viruses. The virophage may improve the recovery and survival of the host organism.

<span class="mw-page-title-main">Sputnik virophage</span>

Mimivirus-dependent virus Sputnik is a subviral agent that reproduces in amoeba cells that are already infected by a certain helper virus; Sputnik uses the helper virus's machinery for reproduction and inhibits replication of the helper virus. It is known as a virophage, in analogy to the term bacteriophage.

<i>Mimiviridae</i> Family of viruses

Mimiviridae is a family of viruses. Amoeba and other protists serve as natural hosts. The family is divided in up to 4 subfamilies. Viruses in this family belong to the nucleocytoplasmic large DNA virus clade (NCLDV), also referred to as giant viruses.

Mamavirus is a large and complex virus in the Group I family Mimiviridae. The virus is exceptionally large, and larger than many bacteria. Mamavirus and other mimiviridae belong to nucleocytoplasmic large DNA virus (NCLDVs) family. Mamavirus can be compared to the similar complex virus mimivirus; mamavirus was so named because it is similar to but larger than mimivirus.

Marseillevirus is a genus of viruses, in the family Marseilleviridae. There are two species in this genus. It is the prototype of a family of nucleocytoplasmic large DNA viruses (NCLDV) of eukaryotes. It was isolated from amoeba.

<i>Cafeteria roenbergensis virus</i> Species of virus

Cafeteria roenbergensis virus (CroV) is a giant virus that infects the marine bicosoecid flagellate Cafeteria roenbergensis, a member of the microzooplankton community.

A giant virus, sometimes referred to as a girus, is a very large virus, some of which are larger than typical bacteria. All known giant viruses belong to the phylum Nucleocytoviricota.

<i>Marseilleviridae</i> Family of viruses

Marseilleviridae is a family of viruses first named in 2012. The genomes of these viruses are double-stranded DNA. Amoeba are often hosts, but there is evidence that they are found in humans as well. The family contains one genus and four species, two of which are unassigned to a genus. It is a member of the nucleocytoplasmic large DNA viruses clade.

<span class="mw-page-title-main">Megavirus</span> Genus of viruses

Megavirus is a viral genus containing a single identified species named Megavirus chilense, phylogenetically related to Acanthamoeba polyphaga Mimivirus (APMV). In colloquial speech, Megavirus chilensis is more commonly referred to as just “Megavirus”. Until the discovery of pandoraviruses in 2013, it had the largest capsid diameter of all known viruses, as well as the largest and most complex genome among all known viruses.

<i>Pandoravirus</i> Genus of giant virus possessing a large double-stranded DNA genome

Pandoravirus is a genus of giant virus, first discovered in 2013. It is the second largest in physical size of any known viral genus. Pandoraviruses have double stranded DNA genomes, with the largest genome size of any known viral genus.

<i>Pithovirus</i> Genus of viruses

Pithovirus, first described in a 2014 paper, is a genus of giant virus known from two species, Pithovirus sibericum, which infects amoebas and Pithovirus massiliensis. It is a double-stranded DNA virus and is a member of the nucleocytoplasmic large DNA viruses clade. The 2014 discovery was made when a viable specimen was found in a 30,000-year-old ice core harvested from permafrost in Siberia, Russia.

Chlorovirus, also known as Chlorella virus, is a genus of giant double-stranded DNA viruses, in the family Phycodnaviridae. This genus is found globally in freshwater environments where freshwater microscopic algae serve as natural hosts. There are 19 species in this genus.

<span class="mw-page-title-main">Zamilon virophage</span>

Mimivirus-dependent virus Zamilon, or Zamilon, is a virophage, a group of small DNA viruses that infect protists and require a helper virus to replicate; they are a type of satellite virus. Discovered in 2013 in Tunisia, infecting Acanthamoeba polyphaga amoebae, Zamilon most closely resembles Sputnik, the first virophage to be discovered. The name is Arabic for "the neighbour". Its spherical particle is 50–60 nm in diameter, and contains a circular double-stranded DNA genome of around 17 kb, which is predicted to encode 20 polypeptides. A related strain, Zamilon 2, has been identified in North America.

<i>Tupanvirus</i> Proposed genus of viruses

Tupanvirus is a genus of viruses first described in 2018. The genus is composed of two species of virus that are in the giant virus group. Researchers discovered the first isolate in 2012 from deep water sediment samples taken at 3000m depth off the coast of Brazil. The second isolate was collected from a soda lake in Southern Nhecolândia, Brazil in 2014. They are named after Tupã (Tupan), a Guaraní thunder god, and the places they were found. These are the first viruses reported to possess genes for amino-acyl tRNA synthetases for all 20 standard amino acids.

<i>Medusavirus</i> Type of virus

Medusavirus is a nucleocytoplasmic large DNA virus first isolated from a Japanese hot spring in 2019. It notably encodes all five types of histones — H1, H2A, H2B, H3, and H4 — which are involved in DNA packaging in eukaryotes, raising the possibility that they may have been involved in the origin of eukaryotes. The virus can harden amoebas of the species Acanthamoeba castellanii into stone-like cysts, but infection usually causes infected amoebas to burst open. The virus was named after Medusa, the monster in Greek mythology whose gaze turned people to stone.

<i>Varidnaviria</i> Realm of viruses

Varidnaviria is a realm of viruses that includes all DNA viruses that encode major capsid proteins that contain a vertical jelly roll fold. The major capsid proteins (MCP) form into pseudohexameric subunits of the viral capsid, which stores the viral deoxyribonucleic acid (DNA), and are perpendicular, or vertical, to the surface of the capsid. Apart from this, viruses in the realm also share many other characteristics, such as minor capsid proteins (mCP) with the vertical jelly roll fold, an ATPase that packages viral DNA into the capsid, and a DNA polymerase that replicates the viral genome.

Nucleocytoviricota is a phylum of viruses. Members of the phylum are also known as the nucleocytoplasmic large DNA viruses (NCLDV), which serves as the basis of the name of the phylum with the suffix -viricota for virus phylum. These viruses are referred to as nucleocytoplasmic because they are often able to replicate in both the host's cell nucleus and cytoplasm.

References

  1. 1 2 3 Klose T, Reteno DG, Benamar S, Hollerbach A, Colson P, La Scola B, Rossmann MG (31 May 2016). "Structure of faustovirus, a large dsDNA virus". Proc Natl Acad Sci U S A. 113 (22): 6206–11. Bibcode:2016PNAS..113.6206K. doi: 10.1073/pnas.1523999113 . PMC   4896704 . PMID   27185929.
  2. 1 2 3 4 5 Reteno DG, Benamar S, Khalil JB, Andreani J, Armstrong N, Klose T, Rossmann M, Colson P, Raoult D, La Scola B (July 2015). "Faustovirus, an asfarvirus-related new lineage of giant viruses infecting amoebae". J Virol. 89 (13): 6585–94. doi:10.1128/JVI.00115-15. PMC   4468488 . PMID   25878099.
  3. ↑ Chatterjee A, Sicheritz-Pontén T, Yadav R, Kondabagil K (March 2019). "Genomic and metagenomic signatures of giant viruses are ubiquitous in water samples from sewage, inland lake, waste water treatment plant, and municipal water supply in Mumbai, India". Scientific Reports. 9 (1): 3690. Bibcode:2019NatSR...9.3690C. doi:10.1038/s41598-019-40171-y. PMC   6403294 . PMID   30842490.
  4. 1 2 Cherif Louazani A, Baptiste E, Levasseur A, Colson P, La Scola B (23 October 2018). "Faustovirus E12 Transcriptome Analysis Reveals Complex Splicing in Capsid Gene". Frontiers in Microbiology. 9: 2534. doi: 10.3389/fmicb.2018.02534 . PMC   6247863 . PMID   30487777.
  5. ↑ Rolland C, Andreani J, Louazani A, Aherfi S, Francis R, Rodrigues R, Silva LS, Sahmi D, Mougari S, Chelkha N, Bekliz M, Silva L, Assis F, Dornas F, Khalil J, Pagnier I, Desnues C, Levasseur A, Colson P, Abrahão J, La Scola B (30 March 2019). "Discovery and Further Studies on Gian Viruses at the IHU Mediterranee Infection That Modified the Perception of the Virosphere". Viruses. 11 (4): 312. doi: 10.3390/v11040312 . PMC   6520786 . PMID   30935049.
  6. 1 2 Temmam S, Monteil-Bouchard S, Sambou M, Adbadie-Ladrix M, Azza S, Deloquement P, Bou Khalil J, Baudoin P, Jardot P, Robert C, La Scola B, Mediannikov O, Raoult D, Desnues C (16 December 2015). "Faustovirus-Like Asfarvirus in Hematophagous Biting Midges and Their Vertebrate Hosts". Frontiers in Microbiology. 6: 1406. doi: 10.3389/fmicb.2015.01406 . PMC   4679923 . PMID   26733117.


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