Extracellular membrane vesicles harbouring viral genomes

Abstract

Summary Cells from the three domains of life produce extracellular membrane vesicles ( MVs ), suggesting that MV production is a fundamental aspect of cellular physiology. We have recently shown that MVs produced by the hyperthermophilic archaeon T hermococcus kodakaraensis can be used as vehicles to transfer exogenous recombinant plasmid DNA from cell to cell. Here, we show that T hermococcus nautilus , which harbours three plasmids, pTN1 , pTN2 and pTN3 , produces MVs , and that some of them selectively incorporate pTN1 and pTN3 . Interestingly, pTN3 represents the genome of a defective virus, which encodes signature proteins common to a large group of viruses infecting hosts from all three cellular domains. However, preparations of MVs produced by T . nautilus have a protein composition similar to that of classical MVs from Thermococcales and do not contain the viral major capsid protein encoded by pTN3 . Our results suggest that MVs can serve as vehicles for the intercellular transport of viral genomes and facilitate recombination between viral, plasmid and/or cellular chromosomes in the absence of viral infection.

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