Paris, March 11, 2011
Discovery of a new bacterial strategy to control immunity
Researchers at the Institut Pasteur, INRA, Inserm and the CNRS have just identified a mechanism that enables the pathogenic bacterium Listeria monocytogenes to reprogram expression of the genes in the host cell it infects to its advantage. L. monocytogenes secretes a protein that can penetrate the cell nucleus and thus take control of the genes in the host’s immune system. This research was published in the journal Science.
This research is coupled to a study carried out by the same team in 2009, which identified a complex capable of blocking gene expression by compacting DNA (2). The researchers identified a small bacterial protein known as LntA that can overcome this block by binding directly to the complex, thereby causing the compacted DNA to open and providing access to the genes.
We still do not know how and at what point the bacterium activates secretion of this LntA factor, but its expression is crucial to the process of infection by Listeria, enabling it to activate or inhibit the host’s immune system at will.
This study points to the role of epigenetic regulation – changes in the expression of genes that occur without any change to the DNA sequence – ininfection by L. monocytogenes. If this discovery is confirmed for other pathogens too, it could provide valuable clues to further our understanding of infectious and immune diseases, and eventually help us to combat them more effectively.
This research has received funding from the European Community (ERANET PathoGenomics and ERC programs).
Hélène Bierne, To Nam Tham, Eric Batsche, Anne Dumay, Morwenna Leguillou, Sophie Kernéis-Golsteyn, Béatrice Regnault, Jacob-S Seeler, Christian Muchardt, Jean Feunteun and Pascale Cossart.
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