Open discussion platform of the COST action EuroMicropH. This discussion series is intended to stimulate an exchange on the different aspects of how microorganisms react to low pH conditions and why people are interested to investigate this subject.
Please register here.
16.12.2022 15:00 CET
Zoom
https://tuwien.zoom.us/j/94155182073?pwd=Nk9MSGlJa2UwR0lvLytlMGpWc3RzUT09
Meeting-ID: 941 5518 2073
Passwort: f0RegR97
Agenda
15:00 Wellcome
15:05 Yoko Eguchi, Kindai University, Japan
What we know about EvgS, an acid responding sensor histidine kinase specific to Escherichia coli
15:30 Aurélia Battesti, CNRS, Marseille, France
The prophage-encoded transcriptional regulator AppY has pleiotropic effects on E. coli physiology
Abstracts
What we know about EvgS, an acid responding sensor histidine kinase specific to Escherichia coli
Yoko Eguchi
Two-component signal transduction systems (TCSs) are widely conserved in bacteria, and contribute to bacterial adaptation against the fluctuating environment. The EvgS/EvgA TCS specific to Escherichia coli responds to mildly acidic pH and regulates expression of drug efflux pump genes as well as various acid resistance genes. In particular, activation of this system induces the expression of GadE, the major transcription factor of the AR2 genes, and thus confers resistance to severe acid stress. However, how, when and where does the sensor histidine kinase, EvgS, become activated have not yet been clearly explained. An up to date summary of EvgS including our work will be introduced together with the many questions that remain to be solved.
The prophage-encoded transcriptional regulator AppY has pleiotropic effects on E. coli physiology
Aurélia Battesti
Bacterial genome diversity is influenced by prophages, which are viral genomes integrated into the bacterial chromosome. Most prophage genes are silent but those that are expressed can provide unexpected properties to their host. We focused our work on AppY, a transcriptional regulator encoded on the DLP12 prophage in E. coli K-12. By performing RNA-Seq experiments, we showed that AppY production modulates the expression of more than 200 genes. Among them, 11 were identified by ChIP-Seq as direct AppY targets. AppY directly and positively regulates several genes involved in the acid stress response including the master regulator gene gadE but also nhaR and gadY, two genes important for biofilm formation. Moreover, AppY indirectly and negatively impacts bacterial motility by favoring the degradation of FlhDC, the master regulator of the flagella biosynthesis. As a consequence of these regulatory effects, AppY increases acid stress resistance and biofilm formation while also causing a strong defect in motility. Our research highlights how a prophage-encoded transcriptional regulator integrates in a complex manner into the host regulatory network and how it benefits its host, allowing it to cope with changing environmental conditions.
