381:
78:
Viral eukaryogenesis has been controversial for several reasons. For one, it is sometimes argued that the posited evidence for the viral origins of the nucleus can be conversely used to suggest the nuclear origins of some viruses. Secondly, this hypothesis has further inflamed the longstanding debate
296:) assembles a nucleus-like structure around the region of genome replication and uncouples transcription and translation, and synthesized mRNA is then transported into the cytoplasm where it undergoes translation. The same researchers also found that this same phage encodes a eukaryotic homologue to
316:
have the apparatus to produce m7G capped mRNA and contain homologues of the eukaryotic cap-binding protein eIF4E. Those supporting viral eukaryogenesis also point to the lack of these features in archaea, and so believe that a sizable gap separates the archaeal groups most related to the eukaryotes
244:
The viral eukaryogenesis hypothesis points to the cell cycle of eukaryotes, particularly sex and meiosis, as evidence. Little is known about the origins of DNA or reproduction in prokaryotic or eukaryotic cells. It is thus possible that viruses were involved in the creation of Earth's first cells.
317:
and the eukaryotes themselves in terms of the nucleus. In light of these and other discoveries, Bell modified his original thesis to suggest that the viral ancestor of the nucleus was an NCLDV-like archaeal virus rather than a pox-like virus. Another piece of supporting evidence is that the
137:
genomes first occurred in the viral world. A DNA-based virus may have provided storage for an ancient host that had previously used RNA to store its genetic information (such host is called ribocell or ribocyte). Viruses may initially have adopted DNA as a way to resist
364:, it would remain within the cell, thus overcoming the tradeoff dilemma typically faced by viruses. With the virus in control of the host cell's molecular machinery, it would effectively become a functional nucleus. Through the processes of mitosis and
228:
because of the balances struck by viruses, which characteristically follow a pattern of tradeoff between infecting as many hosts as possible and killing an individual host through viral proliferation. Hypothetically,
165:. Although this is in contrast to nowadays's more probable eocyte hypothesis, viruses seem to have contributed to the origin of all three domains of life ('out of virus hypothesis'). It has also been suggested that
196:, evolved into a nucleus via gene acquisition from existing bacterial and archaeal species. The lysogenic virus then became the information storage center for the cell, while the cell retained its capacities for
241:. However, this theory is controversial, and additional experimentation involving archaeal viruses is necessary, as they are probably the most evolutionarily similar to modern eukaryotic nuclei.
1046:
Takemura, M. (2020) Medusavirus
Ancestor in a Proto-Eukaryotic Cell: Updating the Hypothesis for the Viral Origin of the Nucleus. Front. Microbiol. 11:571831. doi: 10.3389/fmicb.2020.571831
360:(i.e., a DNA chromosome encapsulated within a lipid membrane). In theory, a large DNA virus could take control of a bacterial or archaeal cell. Instead of replicating and destroying the
65:
and eventually usurping its role. The hypothesis was first proposed by Philip Bell in 2001 and was further popularized with the discovery of large, complex DNA viruses (such as
245:
The eukaryotic nucleus contains linear DNA with specialized end sequences, like that of viruses (and in contrast to bacterial genomes, which have a circular topology); it uses
200:
and general function despite the viral genome's entry. Similarly, the bacterial species involved in this eukaryogenesis retained its capacity to produce energy in the form of
94:
The viral eukaryogenesis hypothesis posits that eukaryotes are composed of three ancestral elements: a viral component that became the modern nucleus; a prokaryotic cell (an
308:
spindle shares several unique properties with eukaryotic spindles: dynamic instability, bipolar filament arrays, and centrally positioning DNA. Further, many classes of
565:"Three RNA cells for ribosomal lineages and three DNA viruses to replicate their genomes: a hypothesis for the origin of cellular domain"
740:
Bell, Philip J. L. (November 2006). "Sex and the eukaryotic cell cycle is consistent with a viral ancestry for the eukaryotic nucleus".
162:
157:, and eukaryotes each obtained their DNA informational system from a different virus. In the original paper it was also an
145:
in the host cells. Hence, the contribution from such a new component may have been as significant as the contribution from
1233:
1223:
631:
1179:
Forterre, Patrick (April 2006). "The origin of viruses and their possible roles in major evolutionary transitions".
1243:
632:"The viral origins of telomeres and telomerases and their important role in eukaryogenesis and genome maintenance"
192:
The viral eukaryogenesis hypothesis depicts a model of eukaryotic evolution in which a virus, similar to a modern
304:) that plays the role of positioning the viral factory in the center of the cell during genome replication. The
257:. Eukaryotic nuclei are also capable of cytoplasmic replication. Some large viruses have their own DNA-directed
421:
250:
246:
177:, have viral origins. Further, the viral origins of the modern eukaryotic nucleus may have relied on multiple
201:
1238:
1218:
886:"Fate of Parasite and Host Organelle DNA during Cellular Transformation of Red Algae by Their Parasites"
416:
254:
954:
749:
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72:
40:
368:, the virus would thus recruit the entire cell as a symbiont—a new way to survive and proliferate.
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capping apparatus (involved in uncoupling of transcription from translation) is present in both
1228:
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1167:
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Forterre, Patrick; Gaïa, M. (June 2016). "Giant viruses and the origin of modern eukaryotes".
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Chaikeeratisak, Vorrapon; Nguyen, Katrina; Khanna, Kanika; et al. (13 January 2017).
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1000:"The Phage Nucleus and Tubulin Spindle Are Conserved among Large Pseudomonas Phages"
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488:
1192:
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Chaikeeratisak, Vorrapon; Nguyen, Katrina; Egan, MacKennon E.; et al. (2017).
808:
791:
357:
150:
24:
349:
Several precepts in the theory are possible. For instance, a helical virus with a
1015:
686:
Takemura, M. (May 2001). "Poxviruses and the origin of the eukaryotic nucleus".
365:
326:
146:
139:
123:
115:
761:
569:
Proceedings of the
National Academy of Sciences of the United States of America
333:
that are considered the nearest archaeal relatives of
Eukarya according to the
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Recent supporting evidence includes the discovery that upon the infection of a
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while also passing much of its genetic information into this new virus-nucleus
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650:
262:
209:
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447:"Viral eukaryogenesis: was the ancestor of the nucleus a complex DNA virus?"
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28:
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943:"Assembly of a nucleus-like structure during viral replication in bacteria"
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cell at the origin of eukaryotes, but eventually more complex, featuring
154:
111:
51:
598:
909:
322:
297:
217:
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95:
47:
142:
62:
54:. The virus later evolved into the eukaryotic nucleus by acquiring
261:. Transfers of "infectious" nuclei have been documented in many
80:
55:
792:"Evidence supporting a viral origin of the eukaryotic nucleus"
375:
318:
221:
158:
134:
130:
1062:"Viruses and cells intertwined since the dawn of evolution"
337:(also supported by the phylogenetic analysis of the m7G
129:
In 2006, researchers suggested that the transition from
391:
1060:
Durzyńska, J.; Goździcka-Józefiak, A. (October 2015).
841:"Genetic material in the early evolution of bacteria"
356:
bears a distinct resemblance to a highly simplified
110:
of modern cells; and another prokaryotic cell (here
511:"Viruses take center stage in cellular evolution"
8:
785:
783:
781:
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735:
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1122:
1105:Hendrickson, H. L.; Poole, A. M. (2018).
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153:. Following this hypothesis, archaea,
445:Bell, Philip J. L. (September 2001).
208:. It is hypothesized that the modern
181:of archaeal cells carrying bacterial
7:
310:nucleocytoplasmic large DNA viruses
14:
790:Bell, Philip J. L. (2020-11-01).
563:Forterre, Patrick (March 2006).
379:
1152:Current Opinion in Microbiology
1193:10.1016/j.virusres.2006.01.010
1107:"Manifold Routes to a Nucleus"
809:10.1016/j.virusres.2020.198168
742:Journal of Theoretical Biology
688:Journal of Molecular Evolution
509:Claverie, Jean-Michel (2006).
451:Journal of Molecular Evolution
1:
1016:10.1016/j.celrep.2017.07.064
173:, key aspects of eukaryotic
233:cycles may mirror those of
1260:
762:10.1016/j.jtbi.2006.05.015
630:Witzany, Guenther (2008).
1164:10.1016/j.mib.2016.02.001
1111:Frontiers in Microbiology
1079:10.1186/s12985-015-0400-7
839:Trevors, Jack T. (2003).
651:10.1007/s12304-008-9018-0
224:occur in all eukaryotes,
79:over whether viruses are
1124:10.3389/fmicb.2018.02604
845:Microbiological Research
422:Endogenous viral element
183:mitochondrial precursors
967:10.1126/science.aal2130
858:10.1078/0944-5013-00171
590:10.1073/pnas.0510333103
528:10.1186/gb-2006-7-6-110
388:This section is empty.
71:) that are capable of
902:10.1105/tpc.7.11.1899
708:10.1007/s002390010171
472:10.1007/s002390010215
417:Endogenous retrovirus
1234:Endosymbiotic events
1224:Evolutionary biology
118:, became the modern
102:) which donated the
73:protein biosynthesis
17:Viral eukaryogenesis
959:2017Sci...355..194C
882:Coleman, Annette W.
754:2006JThBi.243...54B
700:2001JMolE..52..419T
581:2006PNAS..103.3669F
463:2001JMolE..53..251L
272:Supporting evidence
1244:Eukaryote biology
953:(6321): 194–197.
896:(11): 1899–1911.
884:(November 1995).
408:
407:
335:Eocyte hypothesis
312:(NCLDVs) such as
231:viral replication
187:lysogenic viruses
100:eocyte hypothesis
98:according to the
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1066:Virology Journal
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1010:(7): 1563–1571.
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390:You can help by
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358:cellular nucleus
249:, and separates
198:gene translation
175:cell replication
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120:mitochondrion
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108:cell membrane
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41:endosymbiosis
39:in a form of
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35:from a large
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1239:Cell nucleus
1219:Microbiology
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1004:Cell Reports
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748:(1): 54–63.
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670:. Retrieved
663:the original
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639:Biosemiotics
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625:
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518:
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457:(3): 251–6.
454:
450:
440:
396:
392:adding to it
387:
348:
345:Implications
305:
301:
291:
287:
283:, the giant
275:
247:mRNA capping
243:
191:
151:mitochondria
147:chloroplasts
128:
93:
77:
66:
45:methanogenic
25:cell nucleus
16:
15:
1187:(1): 5–16.
372:Other views
366:cytokinesis
329:but not in
327:Mimiviridae
314:mimiviruses
255:translation
124:chloroplast
116:endocytosis
114:) that, by
31:life forms
1213:Categories
851:(1): 1–6.
802:: 198168.
672:2015-05-06
521:(6): 110.
433:References
341:pathway).
293:Phikzvirus
237:and viral
212:, whereby
210:cell cycle
179:infections
167:telomerase
90:Hypothesis
29:eukaryotic
21:hypothesis
1158:: 44–49.
826:221864135
659:207415262
362:host cell
278:bacterial
266:red algae
263:parasitic
206:organelle
194:pox virus
171:telomeres
112:bacterium
104:cytoplasm
84:organisms
68:Mimivirus
58:from the
52:bacterium
43:within a
37:DNA virus
23:that the
1229:Virology
1201:16476498
1172:26894379
1143:30416499
1117:: 2604.
1098:26475454
1034:28813669
985:28082593
928:12242362
867:12608574
818:32961211
770:16846615
724:21200827
716:11443345
617:16505372
599:30048645
547:16787527
489:20542871
481:11523012
411:See also
354:envelope
288:201 Φ2-1
239:lysogens
235:plasmids
155:bacteria
96:archaeon
48:archaeon
1134:6212462
1089:4609113
1072:: 169.
1025:6028189
976:6028185
955:Bibcode
947:Science
910:3870197
750:Bibcode
696:Bibcode
608:1450140
577:Bibcode
538:1779534
459:Bibcode
351:bilipid
339:capping
323:Eukarya
298:tubulin
226:evolved
218:meiosis
214:mitosis
143:enzymes
33:evolved
19:is the
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220:, and
81:living
63:genome
906:JSTOR
822:S2CID
720:S2CID
666:(PDF)
655:S2CID
635:(PDF)
595:JSTOR
485:S2CID
253:from
185:with
56:genes
50:or a
1197:PMID
1168:PMID
1139:PMID
1094:PMID
1030:PMID
981:PMID
924:PMID
863:PMID
814:PMID
766:PMID
712:PMID
613:PMID
543:PMID
477:PMID
325:and
306:PhuZ
302:PhuZ
281:cell
169:and
106:and
60:host
1189:doi
1185:117
1160:doi
1129:PMC
1119:doi
1084:PMC
1074:doi
1020:PMC
1012:doi
971:PMC
963:doi
951:355
914:PMC
898:doi
853:doi
849:158
804:doi
800:289
758:doi
746:243
704:doi
647:doi
603:PMC
585:doi
573:103
533:PMC
523:doi
467:doi
394:.
319:m7G
222:sex
202:ATP
159:RNA
149:or
135:DNA
133:to
131:RNA
122:or
27:of
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