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Dans Nature

Giant virus resurrected from 30,000-year-old ice : Nature News & Comment
▻http://www.nature.com/news/giant-virus-resurrected-from-30-000-year-old-ice-1.14801

Evolutionary biologists Jean-Michel Claverie and Chantal Abergel, the husband-and-wife team at Aix-Marseille University in France who led the work, named it Pithovirus sibericum, inspired by the Greek word ’pithos’ for the large container used by the ancient Greeks to store wine and food. “We’re French, so we had to put wine in the story,” says Claverie.

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Pithovirus has a ‘cork’ with a honeycomb structure capping its opening (see electron-microscope image). It copies itself by building replication ‘factories’ in its host’s cytoplasm, rather than by taking over the nucleus, as most viruses do. Only one-third of its proteins bear any similarity to those of other viruses. And, to the team’s surprise, its genome is much smaller than those of the Pandoraviruses, despite its larger size.

“That huge particle is basically empty,” says Claverie. “We thought it was a property of viruses that they pack DNA extremely tightly into the smallest particle possible, but this guy is 150 times less compacted than any bacteriophage [viruses that infect bacteria]. We don’t understand anything anymore!”

Although giant viruses almost always target amoebae, Christelle Desnues, a virologist at the French National Centre for Scientific Research in Marseilles, last year discovered5 signs that another giant virus, Marseillevirus, had infected an 11-month-old boy.