Virophages of Giant Viruses: An Update at Eleven
Résumé
The last decade has been marked by two eminent discoveries that have changed our
perception of the virology field: The discovery of giant viruses and a distinct new class of viral
agents that parasitize their viral factories, the virophages. Coculture and metagenomics have
actively contributed to the expansion of the virophage family by isolating dozens of new members.
This increase in the body of data on virophage not only revealed the diversity of the virophage group,
but also the relevant ecological impact of these small viruses and their potential role in the dynamics
of the microbial network. In addition, the isolation of virophages has led us to discover previously
unknown features displayed by their host viruses and cells. In this review, we present an update of
all the knowledge on the isolation, biology, genomics, and morphological features of the virophages,
a decade after the discovery of their first member, the Sputnik virophage. We discuss their parasitic
lifestyle as bona fide viruses of the giant virus factories, genetic parasites of their genomes, and then
their role as a key component or target for some host defense mechanisms during the tripartite
virophage–giant virus–host cell interaction. We also present the latest advances regarding their origin,
classification, and definition that have been widely discussed
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Licence : CC BY - Paternité
Licence : CC BY - Paternité