Carmen Buchrieser

Carmen-Buchrieser-180x180Carmen Buchrieser is Professor at the Institut Pasteur, in Paris, France. She obtained her PhD from the University of Salzburg in Austria. 

Her major interest is to understand how bacteria cause disease: what are the genetic factors conferring bacterial virulence, how do they evolve, how to they allow subverting host functions, how do human pathogens emerge. After conducting postdoctoral trainings in the USA and the Institut Pasteur in Paris, she was appointed in 2008 director of the Unit “Biology of Intracellular Bacteria” at the Institut Pasteur, Paris, France. The research activity of her group focuses on investigating the genetic bases of virulence of L. pneumophila and L. longbeachae, The projects of her laboratory are focused on the identification and study of bacterial virulence factors, with particular emphasis on their functions, the mechanisms leading to their acquisition and their evolutionary origin.

Her work has been recognized through a number of membership elections including: German Academy of Science « Leopoldina », EMBO, American Academy of Microbiology, European Academy of Microbiology, Academia Europea.

Post-transcriptional regulatory networks in Legionella pneumophila: key to the survival in extra-and intracellular environments

Legionella pneumophila, the causative agent of the pneumonia-like Legionnaires’ disease, is commonly found in aquatic habitats where it multiplies within protozoa. L. pneumophila is able to survive and replicate in the hostile intracellular environment of a protozoan cell (or a human macrophage during disease). Once L. pneumophila has replicated to high numbers, it is released in the water (or the lung) where low nutrient extracellular conditions are present. To tolerate or exploit these conditions this bacterium has evolved a biphasic lifecycle wherein it alternates between a replicative and a transmissive phase. Genes that allow replication and to scavenge nutrients from the host are expressed when nutrients are available whereas genes that allow transmission and survival in the extracellular environment like virulence factors, motility and resistance against several stress factors are expressed, when nutrients are limited.

The key regulator governing this adaptation thereby allowing the bacterium’s intra- and extracellular survival is the RNA-binding protein CsrA. Transcriptomics, proteomics, RNA-Immunoprecipitation followed by deep sequencing (RIPseq), together with biochemical, phenotypical and molecular analyses allowed us to identify the L. pneumophila CsrA targets genome wide. By comparing a wild type and a csrA mutant strain we identified 478 RNAs with potential CsrA interaction sites and also discovered a new mode of action of CsrA that allows to regulate genes comprised in the same operon, independently.