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Characterization of Mollivirus kamchatka, the First Modern Representative of the Proposed Molliviridae Family of Giant Viruses.
J Virol. 2020 03 31; 94(8)JV

Abstract

Microbes trapped in permanently frozen paleosoils (permafrost) are the focus of increasing research in the context of global warming. Our previous investigations led to the discovery and reactivation of two Acanthamoeba-infecting giant viruses, Mollivirus sibericum and Pithovirus sibericum, from a 30,000-year old permafrost layer. While several modern pithovirus strains have since been isolated, no contemporary mollivirus relative was found. We now describe Mollivirus kamchatka, a close relative to M. sibericum, isolated from surface soil sampled on the bank of the Kronotsky River in Kamchatka, Russian Federation. This discovery confirms that molliviruses have not gone extinct and are at least present in a distant subarctic continental location. This modern isolate exhibits a nucleocytoplasmic replication cycle identical to that of M. sibericum Its spherical particle (0.6 μm in diameter) encloses a 648-kb GC-rich double-stranded DNA genome coding for 480 proteins, of which 61% are unique to these two molliviruses. The 461 homologous proteins are highly conserved (92% identical residues, on average), despite the presumed stasis of M. sibericum for the last 30,000 years. Selection pressure analyses show that most of these proteins contribute to virus fitness. The comparison of these first two molliviruses clarify their evolutionary relationship with the pandoraviruses, supporting their provisional classification in a distinct family, the Molliviridae, pending the eventual discovery of intermediary missing links better demonstrating their common ancestry.IMPORTANCE Virology has long been viewed through the prism of human, cattle, or plant diseases, leading to a largely incomplete picture of the viral world. The serendipitous discovery of the first giant virus visible under a light microscope (i.e., >0.3 μm in diameter), mimivirus, opened a new era of environmental virology, now incorporating protozoan-infecting viruses. Planet-wide isolation studies and metagenome analyses have shown the presence of giant viruses in most terrestrial and aquatic environments, including upper Pleistocene frozen soils. Those systematic surveys have led authors to propose several new distinct families, including the Mimiviridae, Marseilleviridae, Faustoviridae, Pandoraviridae, and Pithoviridae We now propose to introduce one additional family, the Molliviridae, following the description of M. kamchatka, the first modern relative of M. sibericum, previously isolated from 30,000-year-old arctic permafrost.

Authors+Show Affiliations

Aix Marseille Université, CNRS, IGS, Information Génomique & Structurale (UMR7256), Institut de Microbiologie de la Méditerranée (FR 3489), Marseille, France Eugene.christo-foroux@igs.cnrs-mrs.fr jean-michel.claverie@univ-amu.fr.Aix Marseille Université, CNRS, IGS, Information Génomique & Structurale (UMR7256), Institut de Microbiologie de la Méditerranée (FR 3489), Marseille, France.Aix Marseille Université, CNRS, IGS, Information Génomique & Structurale (UMR7256), Institut de Microbiologie de la Méditerranée (FR 3489), Marseille, France.Aix Marseille Université, CNRS, IGS, Information Génomique & Structurale (UMR7256), Institut de Microbiologie de la Méditerranée (FR 3489), Marseille, France.Genoscope, Institut François Jacob, CEA, Université Paris-Saclay, Évry, France.Aix Marseille Université, CNRS, IGS, Information Génomique & Structurale (UMR7256), Institut de Microbiologie de la Méditerranée (FR 3489), Marseille, France.Aix Marseille Université, CNRS, IGS, Information Génomique & Structurale (UMR7256), Institut de Microbiologie de la Méditerranée (FR 3489), Marseille, France.Aix Marseille Université, CNRS, IGS, Information Génomique & Structurale (UMR7256), Institut de Microbiologie de la Méditerranée (FR 3489), Marseille, France Eugene.christo-foroux@igs.cnrs-mrs.fr jean-michel.claverie@univ-amu.fr.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

31996429

Citation

Christo-Foroux, Eugene, et al. "Characterization of Mollivirus Kamchatka, the First Modern Representative of the Proposed Molliviridae Family of Giant Viruses." Journal of Virology, vol. 94, no. 8, 2020.
Christo-Foroux E, Alempic JM, Lartigue A, et al. Characterization of Mollivirus kamchatka, the First Modern Representative of the Proposed Molliviridae Family of Giant Viruses. J Virol. 2020;94(8).
Christo-Foroux, E., Alempic, J. M., Lartigue, A., Santini, S., Labadie, K., Legendre, M., Abergel, C., & Claverie, J. M. (2020). Characterization of Mollivirus kamchatka, the First Modern Representative of the Proposed Molliviridae Family of Giant Viruses. Journal of Virology, 94(8). https://doi.org/10.1128/JVI.01997-19
Christo-Foroux E, et al. Characterization of Mollivirus Kamchatka, the First Modern Representative of the Proposed Molliviridae Family of Giant Viruses. J Virol. 2020 03 31;94(8) PubMed PMID: 31996429.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Characterization of Mollivirus kamchatka, the First Modern Representative of the Proposed Molliviridae Family of Giant Viruses. AU - Christo-Foroux,Eugene, AU - Alempic,Jean-Marie, AU - Lartigue,Audrey, AU - Santini,Sebastien, AU - Labadie,Karine, AU - Legendre,Matthieu, AU - Abergel,Chantal, AU - Claverie,Jean-Michel, Y1 - 2020/03/31/ PY - 2019/11/25/received PY - 2020/01/14/accepted PY - 2020/1/31/pubmed PY - 2020/9/29/medline PY - 2020/1/31/entrez KW - Acanthamoeba KW - Arctic KW - Kamchatka KW - NCLDV KW - comparative genomics KW - paleovirology JF - Journal of virology JO - J Virol VL - 94 IS - 8 N2 - Microbes trapped in permanently frozen paleosoils (permafrost) are the focus of increasing research in the context of global warming. Our previous investigations led to the discovery and reactivation of two Acanthamoeba-infecting giant viruses, Mollivirus sibericum and Pithovirus sibericum, from a 30,000-year old permafrost layer. While several modern pithovirus strains have since been isolated, no contemporary mollivirus relative was found. We now describe Mollivirus kamchatka, a close relative to M. sibericum, isolated from surface soil sampled on the bank of the Kronotsky River in Kamchatka, Russian Federation. This discovery confirms that molliviruses have not gone extinct and are at least present in a distant subarctic continental location. This modern isolate exhibits a nucleocytoplasmic replication cycle identical to that of M. sibericum Its spherical particle (0.6 μm in diameter) encloses a 648-kb GC-rich double-stranded DNA genome coding for 480 proteins, of which 61% are unique to these two molliviruses. The 461 homologous proteins are highly conserved (92% identical residues, on average), despite the presumed stasis of M. sibericum for the last 30,000 years. Selection pressure analyses show that most of these proteins contribute to virus fitness. The comparison of these first two molliviruses clarify their evolutionary relationship with the pandoraviruses, supporting their provisional classification in a distinct family, the Molliviridae, pending the eventual discovery of intermediary missing links better demonstrating their common ancestry.IMPORTANCE Virology has long been viewed through the prism of human, cattle, or plant diseases, leading to a largely incomplete picture of the viral world. The serendipitous discovery of the first giant virus visible under a light microscope (i.e., >0.3 μm in diameter), mimivirus, opened a new era of environmental virology, now incorporating protozoan-infecting viruses. Planet-wide isolation studies and metagenome analyses have shown the presence of giant viruses in most terrestrial and aquatic environments, including upper Pleistocene frozen soils. Those systematic surveys have led authors to propose several new distinct families, including the Mimiviridae, Marseilleviridae, Faustoviridae, Pandoraviridae, and Pithoviridae We now propose to introduce one additional family, the Molliviridae, following the description of M. kamchatka, the first modern relative of M. sibericum, previously isolated from 30,000-year-old arctic permafrost. SN - 1098-5514 UR - https://www.unboundmedicine.com/medline/citation/31996429/Characterization_of_Mollivirus_kamchatka_the_First_Modern_Representative_of_the_Proposed_Molliviridae_Family_of_Giant_Viruses_ L2 - https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/31996429/ DB - PRIME DP - Unbound Medicine ER -