The Campylobacter jejuni Response Regulator and Cyclic-Di-GMP Binding CbrR Is a Novel Regulator of Flagellar Motility

Autor: Claudia A. Cox, Marek Bogacz, Faiha M. El Abbar, Darren D. Browning, Brian Y. Hsueh, Chris M. Waters, Vincent T. Lee, Stuart A. Thompson
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Microorganisms, Vol 10, Iss 1, p 86 (2021)
Druh dokumentu: article
ISSN: 2076-2607
DOI: 10.3390/microorganisms10010086
Popis: A leading cause of bacterial gastroenteritis, Campylobacter jejuni is also associated with broad sequelae, including extragastrointestinal conditions such as reactive arthritis and Guillain-Barré Syndrome (GBS). CbrR is a C. jejuni response regulator that is annotated as a diguanylate cyclase (DGC), an enzyme that catalyzes the synthesis of c-di-GMP, a universal bacterial second messenger, from GTP. In C. jejuni DRH212, we constructed an unmarked deletion mutant, cbrR−, and complemented mutant, cbrR+. Motility assays indicated a hyper-motile phenotype associated with cbrR−, whereas motility was deficient in cbrR+. The overexpression of CbrR in cbrR+ was accompanied by a reduction in expression of FlaA, the major flagellin. Biofilm assays and scanning electron microscopy demonstrated similarities between DRH212 and cbrR−; however, cbrR+ was unable to form significant biofilms. Transmission electron microscopy showed similar cell morphology between the three strains; however, cbrR+ cells lacked flagella. Differential radial capillary action of ligand assays (DRaCALA) showed that CbrR binds GTP and c-di-GMP. Liquid chromatography tandem mass spectrometry detected low levels of c-di-GMP in C. jejuni and in E. coli expressing CbrR. CbrR is therefore a negative regulator of FlaA expression and motility, a critical virulence factor in C. jejuni pathogenesis.
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