Wikipedia

Giant virus

"Girus" redirects here. Not to be confused with Gyrus.

A giant virus, sometimes referred to as a girus, is a very large virus, some of which are larger than typical bacteria.[1][2] All known giant viruses belong to the phylum Nucleocytoviricota.[3]

Description

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While the exact criteria as defined in the scientific literature vary, giant viruses are generally described as viruses having large, pseudo-icosahedral capsids (200 to 400 nanometers in diameter)[4] that may be surrounded by a thick (approximately 100 nm) layer of filamentous protein fibers. The viruses have large, double-stranded DNA genomes (300 to >1000 kilobasepairs) that encode a large contingent of genes (of the order of 1000 genes).[3][5] The best characterized giant viruses are the phylogenetically related mimivirus and megavirus, which belong to the family Mimiviridae (aka Megaviridae), and are distinguished by their large capsid diameters.[3][5] Giant viruses from the deep ocean, terrestrial sources, and human patients contain genes encoding cytochrome P450 (CYP; P450) enzymes. The origin of these P450 genes in giant viruses remains unknown but may have been acquired from an ancient host.[6]

The genomes of many giant viruses encode many unusual genes that are not found in other viruses, including genes involved in glycolysis and the TCA cycle,[7] fermentation,[8] and the cytoskeleton.[9][10][11]

 
Cryo-EM images of the giant viruses CroV and APMV. (A) Cryo-electron micrograph of four CroV particles. (B) Single CroV particle with concave core depression (white arrow). (C) Single APMV particle. Scale bars in (A–C) represent 2,000 Å.
 
Phylogeny of Nucleocytoviricota [12]

History

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The first giant viruses to be described were chloroviruses of the family Phycodnaviridae. These were discovered in 1981 by Russel H. Meints, James L. Van Etten, Daniel Kuczmarski, Kit Lee, and Barbara Ang. The first chlorovirus was initially called HVCV (Hydra viridis Chlorella virus) since it was first found to infect Chlorella-like algae.[13][14]

Other giant viruses that infected marine flagellates were described later. The first mimivirus (BV-PW1) was described in 1995,[15] but was not recognized as such until its sequenced genome was released as Cafeteria roenbergensis virus (CroV) in 2010.[16] Subsequently, the Giant Virus Acanthamoeba polyphaga Mimivirus was characterized[17] (which had been mistaken as a bacterium in 1993),[18] and then sequenced.[19] The term "girus" was coined to refer to the group in 2006.[20]

Genetics and evolution

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The genomes of giant viruses are the largest known for viruses, and contain genes that encode for important elements of translation machinery, a characteristic that had previously been believed to be indicative of cellular organisms. These genes include multiple genes encoding a number of aminoacyl tRNA synthetases, enzymes that catalyze the esterification of specific amino acids or their precursors to their corresponding cognate tRNAs to form an aminoacyl tRNA that is then used during translation.[5] The presence of four aminoacyl tRNA synthetase encoding genes in mimivirus and mamavirus genomes, both species within the Mimiviridae family, as well as the discovery of seven aminoacyl tRNA synthetase genes in the megavirus genome (including those in Mimiviridae) provide evidence that these large DNA viruses may have evolved from a shared cellular genome ancestor by means of genome reduction.[5]

The discovery and subsequent characterization of giant viruses has triggered debate on their evolutionary origins. The two main hypotheses are that they evolved from small viruses by picking up DNA from host organisms; or that they evolved from very complicated organisms via genome reduction, losing various functions including self-reproduction.[21] The possible complicated ancestral organism is also a topic of debate: by one proposal, it might represent a fourth domain of life,[5] but this has been largely discounted.[22][23][24]

Comparison of largest known giant viruses

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Largest giant viruses with complete sequenced genomes as of March 2015
Giant virus name Genome Length Genes Capsid diameter (nm) Hair cover Genbank #
Bodo saltans virus[25] 1,385,869 1227 proteins (predicted) ~300 yes (~40 nm) MF782455
Megavirus chilensis[26] 1,259,197 1120 proteins (predicted) 440 yes (75 nm) JN258408
Mamavirus[27] 1,191,693 1023 proteins (predicted) 500 yes (120 nm) JF801956
Mimivirus[19][28] 1,181,549 979 proteins 39 non-coding 500 yes (120 nm) NC_014649
M4[29] (Mimivirus "bald" variant) 981,813 756 proteins (predicted) 390 No JN036606
Tupanvirus[30] 1,500,000 1276–1425 proteins ≥450+550[31] KY523104
MF405918[32]
Cafeteria roenbergensis virus[33] 617,453 (730 kb) 544 proteins (predicted) 300 No NC_014637

The whole list is in the Giant Virus Toplist created by the Giant Virus Finder software.[34] As of June 11, 2018, there were 183 listed.[35]

Specific common features among giant viruses
Giant virus name Aminoacyl-tRNA synthetase Octocoral-like 1MutS 2Stargate[36] Known virophage[37] Cytoplasmic virion factory Host
Megavirus chilensis 7 (Tyr, Arg, Met, Cys, Trp, Asn, Ile) yes yes no yes Acanthamoeba (Unikonta, Amoebozoa)
Mamavirus 4 (Tyr, Arg, Met, Cys) yes yes yes yes Acanthamoeba (Unikonta, Amoebozoa)
Mimivirus 4 (Tyr, Arg, Met, Cys) yes yes yes yes Acanthamoeba (Unikonta, Amoebozoa)
M4 (Mimivirus "bald" variant) 3 (Met, Cys, Arg) yes yes Resistant yes Acanthamoeba (Unikonta, Amoebozoa)
Cafeteria roenbergensis virus 1 (Ile) yes no yes yes Phagotrophic protozoan (Heterokonta, Stramenopiles)

1Mutator S (MutS) and its homologs are a family of DNA mismatch repair proteins involved in the mismatch repair system that acts to correct point mutations or small insertion/deletion loops produced during DNA replication, increasing the fidelity of replication. 2A stargate is a five-pronged star structure present on the viral capsid forming the portal through which the internal core of the particle is delivered to the host's cytoplasm.

See also

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References

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  1. ^ Reynolds KA (2010). "Mysterious Microbe in Water Challenges the Very Definition of a Virus" (PDF). Water Conditioning & Purification. Archived from the original (PDF) on 2014-03-19.
  2. ^ Ogata H, Toyoda K, Tomaru Y, Nakayama N, Shirai Y, Claverie JM, Nagasaki K (October 2009). "Remarkable sequence similarity between the dinoflagellate-infecting marine girus and the terrestrial pathogen African swine fever virus". Virology Journal. 6 (178): 178. doi:10.1186/1743-422X-6-178. PMC 2777158. PMID 19860921.
  3. ^ a b c Van Etten JL (July–August 2011). "Giant Viruses". American Scientist. 99 (4): 304–311. doi:10.1511/2011.91.304. Archived from the original on 2011-06-21.
  4. ^ Xiao C, Fischer MG, Bolotaulo DM, Ulloa-Rondeau N, Avila GA, Suttle CA (14 July 2017). "Cryo-EM reconstruction of the Cafeteria roenbergensis virus capsid suggests novel assembly pathway for giant viruses". Scientific Reports. 7 (5484): 5484. Bibcode:2017NatSR...7.5484X. doi:10.1038/s41598-017-05824-w. PMC 5511168. PMID 28710447.
  5. ^ a b c d e Legendre M, Arslan D, Abergel C, Claverie JM (January 2012). "Genomics of Megavirus and the elusive fourth domain of Life". Communicative & Integrative Biology. 5 (1): 102–6. doi:10.4161/cib.18624. PMC 3291303. PMID 22482024.
  6. ^ Lamb DC, Follmer AH, Goldstone JV, Nelson DR, Warrilow AG, Price CL, et al. (June 2019). "On the occurrence of cytochrome P450 in viruses". Proceedings of the National Academy of Sciences of the United States of America. 116 (25): 12343–12352. Bibcode:2019PNAS..11612343L. doi:10.1073/pnas.1901080116. PMC 6589655. PMID 31167942.
  7. ^ Moniruzzaman M, Martinez-Gutierrez CA, Weinheimer AR, Aylward FO (2020). "Dynamic genome evolution and complex virocell metabolism of globally-distributed giant viruses". Nature Communications. 11 (1710): 1710. Bibcode:2020NatCo..11.1710M. doi:10.1038/s41467-020-15507-2. PMC 7136201. PMID 32249765.
  8. ^ Schvarcz CR, Steward GF (2018). "A giant virus infecting green algae encodes key fermentation genes". Virology. 518: 423–433. doi:10.1016/j.virol.2018.03.010. PMID 29649682.
  9. ^ Da Cunha V, Gaia M, Ogata H, Jaillon O, Delmont TO, Patrick Forterre P (2020). "Giant viruses encode novel types of actins possibly related to the origin of eukaryotic actin: the viractins". bioRxiv. doi:10.1101/2020.06.16.150565. S2CID 219947620.
  10. ^ Ha AD, Moniruzzaman M, Aylward FO (2021). "High Transcriptional Activity and Diverse Functional Repertoires of Hundreds of Giant Viruses in a Coastal Marine System". mSystems. 6 (4): e0029321. doi:10.1128/mSystems.00293-21. PMC 8407384. PMID 34254826.
  11. ^ Kijima S, Delmont TO, Miyazaki U, Gaia M, Endo H, Ogata H (7 June 2021). "Discovery of Viral Myosin Genes With Complex Evolutionary History Within Plankton". Frontiers in Microbiology. 12: 683294. doi:10.3389/fmicb.2021.683294. PMC 8215601. PMID 34163457.
  12. ^ Aylward FO, Moniruzzaman M, Ha AD, Koonin EV (2021). "A phylogenomic framework for charting the diversity and evolution of giant viruses". PLOS Biology. 19 (10): e3001430. doi:10.1371/journal.pbio.3001430. PMC 8575486. PMID 34705818.
  13. ^ Meints, Russel H.; Van Etten, James L.; Kuczmarski, Daniel; Lee, Kit; Ang, Barbara (September 1981). "Viral infection of the symbiotic chlorella-like alga present in Hydra viridis". Virology. 113 (2): 698–703. doi:10.1016/0042-6822(81)90198-7. PMID 18635088.
  14. ^ Hoshina, Ryo; Shimizu, Mayumi; Makino, Yoichi; Haruyama, Yoshihiro; Ueda, Shin-ichiro; Kato, Yutaka; Kasahara, Masahiro; Ono, Bun-ichiro; Imamura, Nobutaka (13 September 2010). "Isolation and characterization of a virus (CvV-BW1) that infects symbiotic algae of Paramecium bursaria in Lake Biwa, Japan". Virology Journal. 7: 222. doi:10.1186/1743-422X-7-222. ISSN 1743-422X. PMC 2949830. PMID 20831832.
  15. ^ Garza, D. Randy; Suttle, Curtis A. (1995-12-31). "Large double-stranded DNA viruses which cause the lysis of a marine heterotrophic nanoflagellate (Bodo sp) occur in natural marine viral communities" (PDF). Aquatic Microbial Ecology. 9 (3): 133–144. doi:10.3354/ame009203.
  16. ^ Fischer, M. G.; Allen, M. J.; Wilson, W. H.; Suttle, C. A. (2010). "Giant virus with a remarkable complement of genes infects marine zooplankton" (PDF). Proceedings of the National Academy of Sciences. 107 (45): 19508–13. Bibcode:2010PNAS..10719508F. doi:10.1073/pnas.1007615107. PMC 2984142. PMID 20974979.
  17. ^ La Scola B, Audic S, Robert C, Jungang L, de Lamballerie X, Drancourt M, Birtles R, Claverie JM, Raoult D (2003). "A giant virus in amoebae". Science. 299 (5615): 2033. doi:10.1126/science.1081867. PMID 12663918. S2CID 39606235.
  18. ^ "Giant Viruses". American Scientist. 2017-02-06. Retrieved 2021-09-02.
  19. ^ a b Raoult D, Audic S, Robert C, Abergel C, Renesto P, Ogata H, La Scola B, Suzan M, Claverie JM (November 2004). "The 1.2-megabase genome sequence of Mimivirus". Science. 306 (5700): 1344–50. Bibcode:2004Sci...306.1344R. doi:10.1126/science.1101485. PMID 15486256. S2CID 84298461.
  20. ^ Claverie, Jean-Michel; Ogata, Hiroyuki; Audic, Stéphane; Abergel, Chantal; Suhre, Karsten; Fournier, Pierre-Edouard (April 2006). "Mimivirus and the emerging concept of "giant" virus" (PDF). Virus Research. 117 (1): 133–144. arXiv:q-bio/0506007. doi:10.1016/j.virusres.2006.01.008. PMID 16469402. S2CID 8791457.
  21. ^ Bichell RE. "In Giant Virus Genes, Hints About Their Mysterious Origin". All Things Considered.
  22. ^ Schulz F, Yutin N, Ivanova NN, Ortega DR, Lee TK, Vierheilig J, Daims H, Horn M, Wagner M, Jensen GJ, Kyrpides NC, Koonin EV, Woyke T (April 2017). "Giant viruses with an expanded complement of translation system components" (PDF). Science. 356 (6333): 82–85. Bibcode:2017Sci...356...82S. doi:10.1126/science.aal4657. PMID 28386012. S2CID 206655792.
  23. ^ Bäckström D, Yutin N, Jørgensen SL, Dharamshi J, Homa F, Zaremba-Niedwiedzka K, Spang A, Wolf YI, Koonin EV, Ettema TJ (March 2019). "Virus Genomes from Deep Sea Sediments Expand the Ocean Megavirome and Support Independent Origins of Viral Gigantism". mBio. 10 (2): e02497-02418. doi:10.1128/mBio.02497-18. PMC 6401483. PMID 30837339.
  24. ^ Yutin N, Wolf Y, Koonin EV (2014). "Origin of giant viruses from smaller DNA viruses not from a fourth domain of cellular life". Virology. 466–467 (2014): 38–52. doi:10.1016/j.virol.2014.06.032. PMC 4325995. PMID 25042053.
  25. ^ Deeg CM, Chow CT, Suttle CA (March 2018). "The kinetoplastid-infecting Bodo saltans virus (BsV), a window into the most abundant giant viruses in the sea". eLife. 7: e33014. doi:10.7554/eLife.33014. PMC 5871332. PMID 29582753.
  26. ^ Arslan D, Legendre M, Seltzer V, Abergel C, Claverie JM (October 2011). "Distant Mimivirus relative with a larger genome highlights the fundamental features of Megaviridae". Proceedings of the National Academy of Sciences of the United States of America. 108 (42): 17486–91. Bibcode:2011PNAS..10817486A. doi:10.1073/pnas.1110889108. PMC 3198346. PMID 21987820.
  27. ^ Colson P, Yutin N, Shabalina SA, Robert C, Fournous G, La Scola B, Raoult D, Koonin EV (2011). "Viruses with more than 1,000 genes: Mamavirus, a new Acanthamoeba polyphaga mimivirus strain, and reannotation of Mimivirus genes". Genome Biology and Evolution. 3: 737–42. doi:10.1093/gbe/evr048. PMC 3163472. PMID 21705471.
  28. ^ Legendre M, Santini S, Rico A, Abergel C, Claverie JM (March 2011). "Breaking the 1000-gene barrier for Mimivirus using ultra-deep genome and transcriptome sequencing". Virology Journal. 8 (1): 99. doi:10.1186/1743-422X-8-99. PMC 3058096. PMID 21375749.
  29. ^ Boyer, M.; Azza, S.; Barrassi, L.; Klose, T.; Campocasso, A.; Pagnier, I.; Fournous, G.; Borg, A.; et al. (2011). "Mimivirus shows dramatic genome reduction after intraamoebal culture". Proceedings of the National Academy of Sciences. 108 (25): 10296–301. Bibcode:2011PNAS..10810296B. doi:10.1073/pnas.1101118108. PMC 3121840. PMID 21646533.
  30. ^ Abrahão J, Silva L, Silva LS, Khalil JY, Rodrigues R, Arantes T, Assis F, Boratto P, Andrade M, Kroon EG, Ribeiro B, Bergier I, Seligmann H, Ghigo E, Colson P, Levasseur A, Kroemer G, Raoult D, La Scola B (February 2018). "Tailed giant Tupanvirus possesses the most complete translational apparatus of the known virosphere". Nature Communications. 9 (1): 749. Bibcode:2018NatCo...9..749A. doi:10.1038/s41467-018-03168-1. PMC 5829246. PMID 29487281.
  31. ^ head and tail, respectively
  32. ^ soda lake and deep ocean species of Tupanvirues, respectively
  33. ^ Fischer, M. G.; Allen, M. J.; Wilson, W. H.; Suttle, C. A. (2010). "Giant virus with a remarkable complement of genes infects marine zooplankton" (PDF). Proceedings of the National Academy of Sciences. 107 (45): 19508–13. Bibcode:2010PNAS..10719508F. doi:10.1073/pnas.1007615107. PMC 2984142. PMID 20974979.
  34. ^ "Giant Virus Toplist". PIT Bioinformatics Group, Department of Computer Science. Eötvös University. 2015-03-26.
  35. ^ "Giant Virus Toplist". PIT Bioinformatics Group. 26 March 2015. Retrieved 10 May 2023.
  36. ^ Zauberman N, Mutsafi Y, Halevy DB, Shimoni E, Klein E, Xiao C, Sun S, Minsky A (May 2008). Sugden B (ed.). "Distinct DNA exit and packaging portals in the virus Acanthamoeba polyphaga mimivirus". PLOS Biology. 6 (5): e114. doi:10.1371/journal.pbio.0060114. PMC 2430901. PMID 18479185.
  37. ^ Fischer MG, Suttle CA (April 2011). "A virophage at the origin of large DNA transposons". Science. 332 (6026): 231–4. Bibcode:2011Sci...332..231F. doi:10.1126/science.1199412. PMID 21385722. S2CID 206530677.
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