Giant virus: Difference between revisions
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A '''girus''' (a contraction of ''giant virus'' or ''gigantic virus'') is a very large [[virus]].<ref>{{cite journal|last=Reynolds|first=Kelly A.|title=Mysterious Microbe in Water Challenges the Very Definition of a Virus|journal=Water Conditioning & Purification|year=2010|url=http://www.wcponline.com/pdf/June_OnTap.pdf}}</ref><ref>{{cite journal|last=Ogata|first=Hiroyuki|coauthors=Kensuke Toyoda, Yuji Tomaru, Natsuko Nakayama, Yoko Shirai, Jean-Michel Claverie and Keizo Nagasaki|title=Remarkable sequence similarity between the dinoflagellate-infecting marine girus and the terrestrial pathogen African swine fever virus|journal=Virology Journal|year=2009|volume=6|issue=178|doi=10.1186/1743-422X-6-178|url=http://www.virologyj.com/content/6/1/178|accessdate=30 May 2011}}</ref> They are giant [[nucleocytoplasmic large DNA virus]]es (NCLDVs), having unique genes not found in other life, with separate phylogenic trees for those genes.<ref name=AmSci-099-4> American Scientist, "Giant Viruses", '''James L. Van Etten''', ''July-August 2011'', Volume 99, Number 4 </ref> |
A '''girus''' (a contraction of ''giant virus'' or ''gigantic virus'') is a very large [[virus]].<ref>{{cite journal|last=Reynolds|first=Kelly A.|title=Mysterious Microbe in Water Challenges the Very Definition of a Virus|journal=Water Conditioning & Purification|year=2010|url=http://www.wcponline.com/pdf/June_OnTap.pdf}}</ref><ref>{{cite journal|last=Ogata|first=Hiroyuki|coauthors=Kensuke Toyoda, Yuji Tomaru, Natsuko Nakayama, Yoko Shirai, Jean-Michel Claverie and Keizo Nagasaki|title=Remarkable sequence similarity between the dinoflagellate-infecting marine girus and the terrestrial pathogen African swine fever virus|journal=Virology Journal|year=2009|volume=6|issue=178|doi=10.1186/1743-422X-6-178|url=http://www.virologyj.com/content/6/1/178|accessdate=30 May 2011}}</ref> They are giant [[nucleocytoplasmic large DNA virus]]es (NCLDVs), having unique genes not found in other life, with separate phylogenic trees for those genes.<ref name=AmSci-099-4> American Scientist, "Giant Viruses", '''James L. Van Etten''', ''July-August 2011'', Volume 99, Number 4 </ref> |
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The giruses have been controversially proposed as the fourth phylogenic [[domain (biology)|domain]] of [[life]]. (this domain would be separate from the proposed polyphyletic organization of all viruses into a domain for clerical purposes).<ref name=AmSci-099-4/> |
The giruses have been controversially proposed as the fourth phylogenic [[domain (biology)|domain]] of [[life]]. (this domain would be separate from the proposed polyphyletic organization of all viruses into a domain for clerical purposes).<ref name=AmSci-099-4/> |
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==Comparison of largest known giruses== |
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Table 1 : Largest giant viruses with complete sequenced genomes |
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{| class="wikitable" |
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!Giant virus name!!Genome Length!!Genes!!Capsid diameter (nm)!!Hair cover!!Genbank # |
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|Megavirus chilensis<ref name="Doipnas">{{cite journal |doi=10.1073/pnas.1110889108 |title=Distant Mimivirus relative with a larger genome highlights the fundamental features of Megaviridae |year=2011 |last1=Arslan |first1=D. |last2=Legendre |first2=M. |last3=Seltzer |first3=V. |last4=Abergel |first4=C. |last5=Claverie |first5=J.-M. |journal=Proceedings of the National Academy of Sciences |volume=108 |issue=42 |pages=17486}}</ref>||1,259,197||1120 proteins (predicted)||440||yes (75nm)||JN258408 |
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|Mamavirus<ref>{{cite journal |pages=737–42 |doi=10.1093/gbe/evr048 |pmc=3163472 |title=Viruses with More Than 1,000 Genes: Mamavirus, a New Acanthamoeba polyphaga mimivirus Strain, and Reannotation of Mimivirus Genes |year=2011 |last1=Colson |first1=P. |last2=Yutin |first2=N. |last3=Shabalina |first3=S. A. |last4=Robert |first4=C. |last5=Fournous |first5=G. |last6=La Scola |first6=B. |last7=Raoult |first7=D. |last8=Koonin |first8=E. V. |journal=Genome Biology and Evolution |volume=3 |pmid=21705471}}</ref>||1,191,693||1023 proteins (predicted)||390||Yes (120 nm)||JF801956 |
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|Mimivirus<ref name="Raoult2004">{{cite journal |pages=1344–50 |doi=10.1126/science.1101485 |title=The 1.2-Megabase Genome Sequence of Mimivirus |year=2004 |last1=Raoult |first1=D. |journal=Science |volume=306 |issue=5700 |pmid=15486256 |last2=Audic |first2=S |last3=Robert |first3=C |last4=Abergel |first4=C |last5=Renesto |first5=P |last6=Ogata |first6=H |last7=La Scola |first7=B |last8=Suzan |first8=M |last9=Claverie |first9=JM}}</ref><ref>{{cite journal |doi=10.1186/1743-422X-8-99 |pmc=3058096 |title=Breaking the 1000-gene barrier for Mimivirus using ultra-deep genome and transcriptome sequencing |year=2011 |last1=Legendre |first1=Matthieu |last2=Santini |first2=Sébastien |last3=Rico |first3=Alain |last4=Abergel |first4=Chantal |last5=Claverie |first5=Jean-Michel |journal=Virology Journal |volume=8 |pages=99 |pmid=21375749}}</ref>||1,181,549||979 proteins 39 non-coding||390||Yes (120 nm)||NC_014649 |
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Table 2: Specific common features among giant viruses |
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{| class="wikitable" |
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!Giant virus name!!Aminoacyl-tRNA synthetase!!Octocoral-like MutS!!Stargate<ref>{{cite journal |doi=10.1371/journal.pbio.0060114 |pmc=2430901 |title=Distinct DNA Exit and Packaging Portals in the Virus Acanthamoeba polyphaga mimivirus |year=2008 |editor1-last=Sugden |editor1-first=Bill |last1=Zauberman |first1=Nathan |last2=Mutsafi |first2=Yael |last3=Halevy |first3=Daniel Ben |last4=Shimoni |first4=Eyal |last5=Klein |first5=Eugenia |last6=Xiao |first6=Chuan |last7=Sun |first7=Siyang |last8=Minsky |first8=Abraham |journal=PLoS Biology |volume=6 |issue=5 |pages=e114 |pmid=18479185}}</ref>!!Known virophage<ref>{{cite journal |doi=10.1126/science.1199412 |title=A Virophage at the Origin of Large DNA Transposons |year=2011 |last1=Fischer |first1=M. G. |last2=Suttle |first2=C. A. |journal=Science |volume=332 |issue=6026 |pages=231–4 |pmid=21385722}}</ref>!!Cytoplasmic virion factory!!Host |
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|Megavirus chilensis||7 (Tyr, Arg, Met, Cys, Trp, Asn, Ile)||yes||yes||no||yes||Acanthamoeba (Unikonta, Amoebozoa) |
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|Mamavirus||4 (Tyr, Arg, Met, Cys)||yes||yes||yes||yes||Acanthamoeba (Unikonta, Amoebozoa) |
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|Mimivirus||4 (Tyr, Arg, Met, Cys)||yes||yes||yes||yes||Acanthamoeba (Unikonta, Amoebozoa) |
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==References== |
==References== |
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Revision as of 21:49, 4 March 2013
A girus (a contraction of giant virus or gigantic virus) is a very large virus.[1][2] They are giant nucleocytoplasmic large DNA viruses (NCLDVs), having unique genes not found in other life, with separate phylogenic trees for those genes.[3]
While the exact criteria as defined in the scientific literature varies, giruses are generally described as those viruses having large psuedo-icosahedral capsids (200 to 400 nanometers) surrounded by a thick (approximately 100 nm) layer of filamentous protein fibers with large double-stranded DNA genomes (300 to 1000 kilobase pairs or larger) encoding a large contingent of genes (on the order of 1000 genes).[4][3] While few have been characterized in detail, the most notable examples of giruses are the phylogenetically related megavirus and mimivirus, belonging to the megaviridae and mimiviridae families, respectively, having the largest capsid diameters of all known viruses.[4][3]
Viral replication in giruses occurs within large circular virion factories located within the cytoplasm of the infected host cell, similar to the replication mechanism utilized by poxviridae, though whether this mechanism is employed by all giruses or only mimivirus and the related mamavirus has yet to be determined.[4] These virion replication factories are themselves subject to infection by the virophage satellite viruses, which inhibit or impair the reproductive capabilities of the complementary virus.
The giruses have been controversially proposed as the fourth phylogenic domain of life. (this domain would be separate from the proposed polyphyletic organization of all viruses into a domain for clerical purposes).[3]
Comparison of largest known giruses
Table 1 : Largest giant viruses with complete sequenced genomes
| Giant virus name | Genome Length | Genes | Capsid diameter (nm) | Hair cover | Genbank # |
|---|---|---|---|---|---|
| Megavirus chilensis[5] | 1,259,197 | 1120 proteins (predicted) | 440 | yes (75nm) | JN258408 |
| Mamavirus[6] | 1,191,693 | 1023 proteins (predicted) | 390 | Yes (120 nm) | JF801956 |
| Mimivirus[7][8] | 1,181,549 | 979 proteins 39 non-coding | 390 | Yes (120 nm) | NC_014649 |
Table 2: Specific common features among giant viruses
| Giant virus name | Aminoacyl-tRNA synthetase | Octocoral-like MutS | Stargate[9] | Known virophage[10] | 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) |
References
- ^ Reynolds, Kelly A. (2010). "Mysterious Microbe in Water Challenges the Very Definition of a Virus" (PDF). Water Conditioning & Purification.
- ^ Ogata, Hiroyuki (2009). "Remarkable sequence similarity between the dinoflagellate-infecting marine girus and the terrestrial pathogen African swine fever virus". Virology Journal. 6 (178). doi:10.1186/1743-422X-6-178. Retrieved 30 May 2011.
{{cite journal}}: Unknown parameter|coauthors=ignored (|author=suggested) (help)CS1 maint: unflagged free DOI (link) - ^ a b c d American Scientist, "Giant Viruses", James L. Van Etten, July-August 2011, Volume 99, Number 4
- ^ a b c Legendre, Matthieu (2012). "Genomics of Megavirus and the elusive fourth domain of Life". Communicative & Integrative Biology. 5 (1).
{{cite journal}}: Unknown parameter|coauthors=ignored (|author=suggested) (help) - ^ Arslan, D.; Legendre, M.; Seltzer, V.; Abergel, C.; Claverie, J.-M. (2011). "Distant Mimivirus relative with a larger genome highlights the fundamental features of Megaviridae". Proceedings of the National Academy of Sciences. 108 (42): 17486. doi:10.1073/pnas.1110889108.
- ^ Colson, P.; Yutin, N.; Shabalina, S. A.; Robert, C.; Fournous, G.; La Scola, B.; Raoult, D.; Koonin, E. V. (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.
- ^ Raoult, D.; Audic, S; Robert, C; Abergel, C; Renesto, P; Ogata, H; La Scola, B; Suzan, M; Claverie, JM (2004). "The 1.2-Megabase Genome Sequence of Mimivirus". Science. 306 (5700): 1344–50. doi:10.1126/science.1101485. PMID 15486256.
- ^ Legendre, Matthieu; Santini, Sébastien; Rico, Alain; Abergel, Chantal; Claverie, Jean-Michel (2011). "Breaking the 1000-gene barrier for Mimivirus using ultra-deep genome and transcriptome sequencing". Virology Journal. 8: 99. doi:10.1186/1743-422X-8-99. PMC 3058096. PMID 21375749.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ Zauberman, Nathan; Mutsafi, Yael; Halevy, Daniel Ben; Shimoni, Eyal; Klein, Eugenia; Xiao, Chuan; Sun, Siyang; Minsky, Abraham (2008). Sugden, Bill (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.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ Fischer, M. G.; Suttle, C. A. (2011). "A Virophage at the Origin of Large DNA Transposons". Science. 332 (6026): 231–4. doi:10.1126/science.1199412. PMID 21385722.
See also
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