Characterization of a two-component system inPseudomonas aeruginosa: Regulation and involvement in resistance to heavy metals

Diplôme Master Characterization of a two-component system inPseudomonas aeruginosa: Regulation and involvement in resistance to heavy metals eng 2024-02-15 author Thomasson Emma 979916 director Perron Karl 45679 Département des sciences végétales (BIVEG) 58 Pseudomonas aeruginosa is a ubiquitous Gram-negative environmental bacterium that can be isolated from a wide range of habitats and hosts. Its diversity and genetic complexity allow it to adapt to changing environments and exhibit high pathogenicity. It is a clinically important pathogen with the ability to resist antibiotics and heavy metals, attributed to its low membrane permeability and efflux mechanisms. Moreover, this organism serves as a noteworthy model for studying two- component systems' regulation, which are major players in exogenous signal transduction. Regulatory mechanisms enable P. aeruginosa to thrive in both host-associated and non-associated environments. Response regulators (RR), often activated by their sensor histidine kinase (HK), play a crucial role in gene expression regulation. Their function involves activating or repressing gene expression, orchestrating essential cellular processes. Therefore, the characterization of transcription factors (TFs) and their targets is vital in biological research. The aim of this study is to characterise a two-component system, IrlRS, studied for the first time in Burkholderia pseudomallei due to its involvement in the regulation of heavy metal resistance and host invasion. However, information about it in P. aeruginosa is practically nonexistent. We determined that IrlR binds to the promoters of genes czcR and copR, encoding two regulators capable of activating the CzcCBA efflux pump, thus involved in heavy metal resistance. In addition to numerous connections with genes related to heavy metal import and export, this two-component system also possesses mechanisms to survive in case of excess zinc or cobalt and seems to be linked to zinc homeostasis in the bacterium Escherichia coli. Finally, we report here that the transcriptional control of IrlRS relies on the metal-dependent phosphatase activity of IrlS. The phosphorylation of IrlR is likely independent of IrlS, and the gene activation by this system as well. However, in the absence of certain metals such as cobalt or zinc, IrlS dephosphorylates IrlR, rendering it inactive. Dewey 580 Master de Biologie, Orientation Libre 45 Département des sciences végétales 163 false 1239 Unité de microbiologie bbe09047-7181-4fa0-9b9a-5b56350b3deb Master thesis Restricted Master thesis final.pdf 4356322 application/pdf fa30877e0546e833634bdd262d6bf3419fc8bfd417b4bf1fdb8c4de111ffed9b restrictedAccess Faculté des sciences / Section de biologie / Département des sciences végétales

Title	Published in	Access level	OA Policy	Year	Views	Downloads

Characterization of a two-component system inPseudomonas aeruginosa: Regulation and involvement in resistance to heavy metals				2024	112	1

Archive ouverte UNIGE

Thomasson, Emma

account_balance Affiliation entities

Research groups

Affiliation entities