Manipulation of cellular syntheses and the nature of viruses: The virocell concept

Recently, several authors have suggested that viruses are ancient organisms that should be introduced in evolutionary scenarios describing the history of life. However, these views have been strongly disputed by authors who support the traditional view of viruses as byproducts of cellular activity. For a long time, viruses have been indeed confused with virions, inert particles without metabolic activity, excluding them from the realm of life. I introduce here the concept of virocell, to put emphasis on the intracellular phase of the virus life cycle. This concept posits that viruses are cellular - thus living - organisms, and highlight the capacity of viruses to create new genes to manipulate their cellular environment and to create novel biological mechanisms. This concept helps to explain why viruses have played a major role in the history of life. It suggests to mine more systematically the viral world to find new tools for synthetic biology. (C) 2010 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.