Molecular Biology of Gene in Extremophiles  


  HEADPr FORTERRE Patrick / forterre@pasteur.fr
  MEMBERSDr BASTA-LE BERRE Tamara / BIZE Ariane / CORTEZ Diego / COVA RODRIGUES Ana / Dr Alexis CRISCUOLO / Dr DEBARBIEUX Laurent / DESMOND Elie / DESNOUES Nicole / Dr ELMERICH Claudine / Dr GRIBALDO Simonetta / JAUBERT Carole / PEIXEIRO Nuno / Dr LUCAS-STAAT Soizick / MAURA Damien / MOCHIZUKI Tomohiro / Dr MORELLO Eric / PINA Mery / Dr PRANGISHVILI David / Dr REDDER Peter / Dr SEZONOV Guennadi / TERRAS Chloé


  Annual Report

The division of the cellular living world 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).

We are now studying DNA replication and transcription of several of these viruses. This year, we found that infection of an Acidianus strain by a rudivirus inhibits the replication of a plasmid present in this strain, a type of plasmid/virus interaction never described previously. We are now looking for further viruses in new extremely hot environments (Kamtchatka, Clermont-Ferrand and Iceland hot springs) and in high salt environments in Senegal dominated by extremely halophilic archaea.

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 have also initiated a collaboration to explore the potential of archaeal viruses in nanotechnology.

Our interest for microbial viruses led us to incubate a new project on phage therapyled by L. Debarbieux. Several new viruses infecting pathogenic bacteria have been isolated and a mouse model has been successfully 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 integration of viral and plasmids are even more frequent than currently thought, and that most ORFans in archaeal and acterial genomes are of viral origin. We also performed several phylogenomic analyses to understand the origin and evolution of major molecular mechanisms, such as aerobic respiration. Our phylogenies of the translation and transcription apparatus help to set up a robust phylogeny of the archaeal domain and led to the proposal of a new archaeal phylum, the Thaumarchaea.

Keywords: Archaea, viruses, Phage therapy, Comparative genomics, Replication, Transcription, Molecular phylogeny, Evolution

Bmge.jpg

The ampullavirus ABVAcidianus Bottle-shaped Virus



  Publications

BROCHIER-ARMANET C., BOUSSAU B., GRIBALDO S. & FORTERRE P. 2008.Mesophilic crenarchaea: proposal for a third archaeal phylum, the Thaumarchaeota.Nature Rev Microbiol, 6, 245-52.

FORTERRE P. 2006.Three RNA cells for ribosomal lineages and three DNA viruses to replicate their genomes: a hypothesis for the origin of cellular domain. Proc. Natl. Acad. Sci ., 103 (10), 3669-3374 .

PENG X., BASTA T., HARING M., GARRETT R.A. &PRANGISHVILI D. 2007.Genome of Acidianusbottle-shaped virus and insights into the replication and packaging mechanisms. Virology364, 237-243.

PRANGISHVILI D., FORTERRE P. & GARRETT R. 2006.
Viruses of the Archaea : a unifying view. Nat Rev Microbiol , 4, 837-848.

STEINMETZ N. F., BIZE A., FINDLAY K.C., LOMONOSSOFF G.P., MANCHESTER M., EVANS D.J. & PRANGISHVILI D. 2008.Site-specific and spatially controlled addressability of a new viral nanobuilding block: Sulfolobus islandicus Rod-shaped Virus 2.Advanced Functional Materials, 18(1), 3478-3486.* Highlighted in Nature Biotech.



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Activity Reports 2009 - Institut Pasteur
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