Résumé
Bacteria use their cell wall to protect themselves from different stresses such as changes in osmolites concentration. Quintero-Yanes et al. (2022) recently described ChvG as a histidine kinase (HK) sensing damages to the peptidoglycan (PG) layer due to osmotic upshift in the oligotrophic bacterium Caulobacter crescentus. The Chv (Chromosome virulence factor) two-component system (TCS) has first been highlighted in Agrobacterium tumefaciens as a pathogenic regulator responding to acidic pH. This TCS is composed of the ChvG HK and the ChvI response regulator (RR). In C. crescentus, ChvGI is activated when exposed to acidic conditions, treatment with mitomycin C or cultured in synthetic minimal media. Additionally, ChvG localization has been previously described as displaying a patchy-spotty (P/S) localization typically observed with PG-related proteins. Quintero-Yanes et al. (2022) confirmed those data and further assessed its localization upon cell envelope stress, such as osmotic upshift. Upon osmotic shock, ChvG is able to relocate at mid-cell and that pattern of relocation is reminiscent to what was described with PG-related proteins. Nevertheless, the role of that relocation remains unknow. Furthermore, ChIP-seq and RNA-seq experiment done to uncover the ChvI regulon revealed cell envelope architecture as a key regulated cellular process. Indeed, many genes involved in cell division, morphology and PG synthesis were found to be regulated by ChvGI.In this work, we have been focused on studying subcellular localization of proteins being part of the ChvI regulon and hypothesized to be active upon hyperosmotic shock. On the other hand, the study performed by Werner et al. (2009) in which they focused on protein localization in C. crescentus helped us to confirm some of our results. Here, we show that that the relocation pattern observed with ChvG seems to be conserved among stress-related proteins by using fluorescence microscopy.
Furthermore, studying protein-protein interaction between our candidates and PG-related proteins helped us to propose a model concerning protein relocation.
| la date de réponse | 30 janv. 2023 |
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| langue originale | Anglais |
| L'institution diplômante |
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| Superviseur | Regis Hallez (Promoteur) |