Group leader, Professor
EPFL, Lausanne, Suisse
Adult fly injected with bacteria the Green Fluorescent Protein.
Bruno Lemaitre and his research group are investigating mechanisms regulating the interactions between animals and microorganisms. They study both microbial infections (the host defense responses to a pathogenic situation), and symbiotic situations (when the interaction is mutually beneficial for the fly and the bacteria). They also explore what makes the gut an efficient barrier against infections, despite its constant contact with microbes. They use the fruit fly (Drosophila melanogaster) as a model animal, which shares molecular and physiological traits evolutionarily conserved with many animals, including humans.
Bruno Lemaitre and his team use Drosophila and its powerful genetics on three main axes of research focusing on:
1) Drosophila innate immunity
The Lemaitre’s lab research focuses on understanding mechanisms of microbial infection and corresponding host defense responses in Drosophila using genetic and genomic approaches. They employ genetic screens to identify novel factors regulating the immune response of Drosophila. These studies extend our understanding of how the Toll and Imd NF-B pathways activate antimicrobial defense, as well as how the host recognizes and distinguishes between different microbial pathogens. They are also analyzing the strategies used by entomopathogenic bacteria to subvert the Drosophila innate immune system and have a long-standing interest in the gut immune response.
2) The Drosophila-Spiroplasma interaction: a model for insect endosymbiosis
Virtually every species of insect harbours facultative bacterial endosymbionts (ex. Wolbachia) that are transmitted from females to their offsprings. These symbionts play crucial roles in the biology of their hosts. Some manipulate host reproduction, for example, by killing the sons of infected females, in order to spread within host populations. Other symbionts protect their hosts against natural pathogens and parasites. However, in spite of growing interest in endosymbionts, very little is known about the molecular mechanisms underlying most endosymbiont-insect interactions. Bruno Lemaitre and his team are studying the interaction between Drosophila and its endosymbiont Spiroplasma poulsonii. They are using a broad range of approaches ranging from molecular genetics to genomics to dissect the molecular mechanisms underlying key features of the symbiosis, including vertical transmission, male killing, regulation of symbiont growth, and symbiont-mediated protection against pathogens. They believe that the fundamental knowledge generated by studying the Drosophila-Spiroplasma interaction will serve as a paradigm for other endosymbiont-insect interactions that are less amenable to genetic studies.
3) The digestive tract: a compartmentalized and dynamic barrier
The gut has also been a relatively understudied organ in Drosophila melanogaster. Using an integrated approach, Bruno Lemaitre and his group are studying the mechanisms that make the gut an efficient barrier, despite its constant interactions with microbes. They are also examining the regulatory mechanisms that restore normal gut function upon challenge with bacteria. They have recently studied the role of intestinal stem cells in gut repair during bacterial infection. In parallel with these studies, they have generated a comprehensive atlas of the morphological and functional properties of the compartments of the Drosophila gut. They are following up on this work by studying the gene regulatory networks that govern gut region identity, and by trying to understand the impact of compartmentalization on various gut functions such as immunity and digestion.
Dernière mise à jour : 31 juillet 2014
• 1992 PhD, Institut Jacques Monod, Paris, France, Dario Coen's lab
• 1992-1998 Appointed Research associate (CNRS CR, permanent position), IBMC, Strasbourg, France, Jules Hoffmann's lab
• 1998 Appointed Group leader, CNRS, Gif-sur-Yvette, France
• Advanced Investigator Grant of the European Research Council (ERC), 2013
• Lilliane Bettencourt Prize (Life sciences), 2010
• Lucien Tartois Prize from the FRM, 2006
• William B. Coley Award from the American Cancer Research Institute, 2003
• Prize of the French Academy of Science (Noury, Thorlet, Becquerel et Lazare), 2001
Publication of a book: An Essay on Science and Narcissism
Accumulation of differentiating intestinal stem cell progenies drives tumorigenesis.
Déc 2015, Nat Commun