Molecular Biology of Gene in Extremophiles

David Prangishvili et Patrick Forterre
The living world is presently divided into three cellular lineages: the Bacteria, the Archaea and the Eucarya. We are interested in the events and mechanisms that lead to the establishment of these three lineages and in the role that viruses have played in that history. The main research axis of our unit focuses on studying viruses of hyperthermophilic Archaea. These viruses are much more diverse than those infecting bacteriaand their virions display unique morphotypes, opening new questions on the origin of viruses and their relationships with cellular organisms. We are studying at the molecular level DNA replication and transcription for several viruses as well as their interactions with their hosts. We are also exploring these highly stable viruses for their potential application in nanotechnologies.

Beside these experimental studies, we are studying several fundamental questions related to microbial evolution using in silico methods. Several microbial phylogenomic analyses have been developped to understand the historic evolution of the three cellular lineages. We are particularly interested in the phylogeny of microorganisms, and in the emergence and evolution of various key cellular structures and processes, with a focus on the evolutionary links among the three domains of life.

Our interest for viruses infecting microbes leaded us to develop a new project focusing on the study of interactions between bacteriophages and bacteria in animals. Several new viruses infecting bacterial pathogens have been isolated. Their in vivo characterization using two animal models revealed the therapeutic potential of these bacteriophages.

Mots-clés: Archaea, Viruses, Evolution, Microbial Phylogeny, Bacteriophages and Therapy.

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