Société Française de Biochimie et Biologie Moléculaire

Emma Desgranges - September 2019

Architecture et Réactivité de l'ARN, CNRS, Université de Strasbourg, Strasbourg, France A multifaceted small RNA modulates gene expression upon glucose limitation in Staphylococcus aureus EMBO J. 2019 Feb 13. pii: e99363. doi: 10.15252/embj.201899363 Bronesky D♯, Desgranges E♯, Corvaglia A, François P, Caballero CJ, Prado L, Toledo-Arana A, Lasa I, Moreau K, Vandenesch F, Marzi S, Romby P*, Caldelari I*


Emma Desgranges, 26 years old, obtained a master degree in Biology of Micro-organisms with the specialty “Microbiology” at the University of Strasbourg in 2016. She is currently accomplishing a phD thesis under Isabelle Caldelari and Pascale Romby’s supervision (IBMC, CNRS, University of Strasbourg). The aim of her work is to characterizes the function of regulatory RNAs (sRNA) in the metabolism and virulence of the pathogen bacterium Staphylococcus aureus. Part of the study in collaboration with Delphine Bronesky has shown that RsaI sRNA is induced when glucose concentration decreases in the extracellular medium and growth is arrested. By interacting with its target mRNAs or other regulatory RNAs, it allows the bacterium to modify its metabolism to face environmental changes. This work lead to the publication of the article "A small multi-faceted RNA modulates gene expression during glucose limitation in Staphylococcus aureus." In the journal EMBO Journal the January 21, 2019.


Emma Desgranges

2, Allée Conrad Roentgen 67 084 Strasbourg


Pathogenic bacteria must rapidly adapt to ever‐changing environmental signals resulting in metabolism remodeling. The carbon catabolite repression, mediated by the catabolite control protein A (CcpA), is used to express genes involved in utilization and metabolism of the preferred carbon source. Here, we have identified RsaI as a CcpA‐repressed small non‐coding RNA that is inhibited by high glucose concentrations. When glucose is consumed, RsaI represses translation initiation of mRNAs encoding a permease of glucose uptake and the FN3K enzyme that protects proteins against damage caused by high glucose concentrations. RsaI also binds to the 3′ untranslated region of icaR mRNA encoding the transcriptional repressor of exopolysaccharide production and to sRNAs induced by the uptake of glucose‐6 phosphate or nitric oxide. Furthermore, RsaI expression is accompanied by a decreased transcription of genes involved in carbon catabolism pathway and an activation of genes involved in energy production, fermentation, and nitric oxide detoxification. This multifaceted RNA can be considered as a metabolic signature when glucose becomes scarce and growth is arrested.