CE11 - Caractérisation des structures et relations structure-fonctions des macromolécules biologiques

Exploration of transpovirons propagation within Mimiviridae – TransVIR

Submission summary

The Mimiviridae, overlapping in size and genome complexity with unicellular organisms are among the most unexpected discoveries of the last 15 years in biology. This family of viruses infecting amoeba is divided in three clades and all share an exclusively cytoplasmic infectious cycle making them the target of viral infections by true viruses of viruses, the Virophages. Virophages use the same regulatory signals as their host viruses and hijack the viral factory for their own replication. Mimiviridae can also be found associated with puzzling small linear double stranded DNA that were coined Transpoviron. Their genomes encode 6 to 8 proteins and exhibit variable genomic signatures depending on the clade of virus they are associated with. Strikingly, the transpovirons depend only on the giant virus to replicate while they can also use the virophage as a vehicle to propagate. They are also able to integrate into the genomes of giant viruses and virophages. However, the role of the transpovirons in this complex relationship as well as the molecular mechanisms underlying the association between these different partners remain to be elucidated. In this project, we propose to structurally and functionally characterize the transpoviron proteins, investigate the role of the genomic signatures specific to each clade and identify the complex interaction networks they build with the different partners (giant virus/virophage/host cell), through a multidisciplinary effort combining proteomic, transcriptomic, structural, functional and cellular biology studies. We also propose to elucidate the integration mechanisms of transpoviron, which in light of the functional data for each protein, will provide us with an ideal entry point for the design of genetic tools sorely lacking at present, for the genetic manipulation of the giant viruses and virophages genomes. This project should thus provide the keys to understand the true nature of the transpovirons, their origin as well as their contribution to the evolution of giant viruses in their association with virophages and their cellular host.

Project coordination

Sandra Jeudy (Information génomique et structurale)

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.


IGS Information génomique et structurale

Help of the ANR 428,371 euros
Beginning and duration of the scientific project: December 2020 - 48 Months

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