Molecular Biology of Gene in Extremophiles

  HEADProf. FORTERRE Patrick /
  MEMBERSDr BASTA Tamara / BIZE Ariane / Dr CLEMENT Jean-Marie / CORTEZ Diego
Dr DEBARBIEUX Laurent / DESMOND Elie / Dr GRIBALDO Simonetta / Dr LUCAS-STAAT Soizick
Dr PRANGISHVILI David / Dr Peter REDDER / Dr SEZONOV Guennadi / TERRAS Chloé

  Annual Report

The division of the cellular living word into three domains, Archaea, Bacteria and Eukarya, has opened a new area in the exploration of the microbial world and in evolutionary studies. The major research axis in our unit is the study of viruses from hyperthermophilic archaea. D. Prangishvili has discovered and/or described several new families of viruses infecting Sulfolobus or Acidianus species: the Rudiviridae, the Lipothrixviridae, the Globuloviridae, the Ampullaviridae (Figure 1), and the Bicaudaviridae (which exhibits a unique developmental cycle of the virion).

These viruses exhibit unique morphotypes, raising new questions about the origin of viruses and their relationships with cellular organisms. We are now looking for new viruses in extremely hot environments (Kamtchatka and Iceland hot springs) and we are studying DNA replication and transcription in our previously described viruses. Most genes of hyperthermophilic viruses encode unknown proteins. We have initiated, in collaboration with external laboratories, two structural genomic projects to identify their structures and possible functions. We will also start this year a whole genome transcriptional study to analyze host-virus interactions in our model organism Sulfolobus islandicus. We are especially interested in the possible role of the CRISP elements (ubiquitous in Archaea and present in 50% of bacterial genomes) in host resistance to infection.

Our interest for microbial viruses led us to incubate a new project on phage therapy led by L. Debarbieux. Several new viruses infecting pathogenic bacteria have been isolated and a new animal model is tested to help establishing rational approaches for phage therapy.

In parallel to these experimental studies, S. Gribaldo and P. Forterre supervise in silico research projects to tackle fundamental evolutionary questions. We have set up a new method based on comparative genomics to detect integrated viruses in archaeal and bacterial genomes. Our results suggest that most ORFans in these genomes are of viral origin. We also performed several phylogenomic analyses to understand the origin and evolution of major molecular mechanisms in the three domains of life. Our phylogenies of the translation and transcription apparatus help to set up a robust phylogeny of the archaeal domain.


Figure 1 : The ampullavirus ABV Acidianus Bottle-shaped Virus.

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More informations on our web site


Publications 2006 of the unit on Pasteur's references database

Activity Reports 2006 - Institut Pasteur
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