Mirusviruses link herpesviruses to giant viruses

Morgan Gaïa (1, 2) , Lingjie Meng (3) , Eric Pelletier (1, 2) , Patrick Forterre (4, 5) , Chiara Vanni (6) , Antonio Fernandez-Guerra (7) , Olivier Jaillon (1, 2) , Patrick Wincker (1, 2) , Hiroyuki Ogata (3) , Mart Krupovic (8) , Tom O Delmont (1, 2)

1 UMR 8030 - Génomique métabolique
2 GOSEE - Global Oceans Systems Ecology & Evolution - Tara Oceans
3 Kyoto University
4 I2BC - Institut de Biologie Intégrative de la Cellule
5 Département de Microbiologie - Department of Microbiology
6 Universität Bremen
7 UCPH - University of Copenhagen = Københavns Universitet
8 Virologie des archées - Archaeal Virology

DNA viruses have a major influence on the ecology and evolution of cellular organisms 1–4 , but their overall diversity and evolutionary trajectories remain elusive 5 . Here we carried out a phylogeny-guided genome-resolved metagenomic survey of the sunlit oceans and discovered plankton-infecting relatives of herpesviruses that form a putative new phylum dubbed Mirusviricota . The virion morphogenesis module of this large monophyletic clade is typical of viruses from the realm Duplodnaviria 6 , with multiple components strongly indicating a common ancestry with animal-infecting Herpesvirales . Yet, a substantial fraction of mirusvirus genes, including hallmark transcription machinery genes missing in herpesviruses, are closely related homologues of giant eukaryotic DNA viruses from another viral realm, Varidnaviria . These remarkable chimaeric attributes connecting Mirusviricota to herpesviruses and giant eukaryotic viruses are supported by more than 100 environmental mirusvirus genomes, including a near-complete contiguous genome of 432 kilobases. Moreover, mirusviruses are among the most abundant and active eukaryotic viruses characterized in the sunlit oceans, encoding a diverse array of functions used during the infection of microbial eukaryotes from pole to pole. The prevalence, functional activity, diversification and atypical chimaeric attributes of mirusviruses point to a lasting role of Mirusviricota in the ecology of marine ecosystems and in the evolution of eukaryotic DNA viruses.

Domaines: Virologie

Morgan Gaïa, Lingjie Meng, Eric Pelletier, Patrick Forterre, Chiara Vanni, et al.. Mirusviruses link herpesviruses to giant viruses. Nature, 2023, 616 (7958), pp.783-789. ⟨10.1038/s41586-023-05962-4⟩. ⟨pasteur-04085734⟩