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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Produce Safety and Microbiology Research » Research » Publications at this Location » Publication #304649

Research Project: Molecular Biology of Human Pathogens Associated with Food

Location: Produce Safety and Microbiology Research

Title: The Campylobacter jejuni CprRS two-component regulatory system regulates aspects of the cell envelope

Author
item Svensson, Sarah - University Of British Columbia
item Huynh, Steven
item Parker, Craig
item Gaynor, Erin - University Of British Columbia

Submitted to: Molecular Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/13/2015
Publication Date: 4/1/2015
Citation: Svensson, S., Huynh, S., Parker, C., Gaynor, E.C. 2015. The Campylobacter jejuni CprRS two-component regulatory system regulates aspects of the cell envelope. Molecular Microbiology. 96:189-209.

Interpretive Summary: As a leading cause of foodborne bacterial gastroenteritis, Campylobacter jejuni is a significant human pathogen. C. jejuni lives commensally in the gastrointestinal tract of animals, but tolerates variable environments during transit to a susceptible host. A two-component regulatory system, CprRS, was previously identified in C. jejuni, which contains an essential response regulator (CprR) and affects biofilm formation. Further molecular analysis was undertaken to understand how CprRS affects survival. Expression of the system was highest in log phase and dependent on the CprS sensor kinase. A point mutant form of CprR (CprRD52A) did not support viability, suggesting CprR phosphorylation is essential, despite dispensability of CprS. One-hybrid was used to construct a consensus sequence bound by the C-terminal domain of CprR. The phosphoacceptor D52 residue was required for binding of full-length CprR to this sequence. Microarray analysis of the 'cprS sensor kinase mutant, together with the location of putative CprR-binding sites, identified candidate members of the CprRS regulon. CprRS appears to control cell envelope-related genes, including the adjacent htrA gene (periplasmic serine protease), as well as peb4 (SurA-like chaperone). A putative consensus in the htrA promoter was bound by the C-terminal domain of CprR, consistent with direct regulation by CprRS. Finally, (like 'cprS) biofilms were modestly increased in 'htrA, and 'cprS enhanced biofilms were suppressed by Mg2+, suggesting dysregulation of envelope-related genes may underlie this phenotype. Thus, CprRS may regulate maintenance of the cell envelope, a structure that serves as the first line of interaction between pathogen and changing environments during pathogenesis.

Technical Abstract: As a leading cause of foodborne bacterial gastroenteritis, Campylobacter jejuni is a significant human pathogen. C. jejuni lives commensally in the gastrointestinal tract of animals, but tolerates variable environments during transit to a susceptible host. A two-component regulatory system, CprRS, was previously identified in C. jejuni, which contains an essential response regulator (CprR) and affects biofilm formation. Further molecular analysis was undertaken to understand how CprRS affects survival. Expression of the system was highest in log phase and dependent on the CprS sensor kinase. A point mutant form of CprR (CprRD52A) did not support viability, suggesting CprR phosphorylation is essential, despite dispensability of CprS. One-hybrid was used to construct a consensus sequence bound by the C-terminal domain of CprR. The phosphoacceptor D52 residue was required for binding of full-length CprR to this sequence. Microarray analysis of the 'cprS sensor kinase mutant, together with the location of putative CprR-binding sites, identified candidate members of the CprRS regulon. CprRS appears to control cell envelope-related genes, including the adjacent htrA gene (periplasmic serine protease), as well as peb4 (SurA-like chaperone). A putative consensus in the htrA promoter was bound by the C-terminal domain of CprR, consistent with direct regulation by CprRS. Finally, (like 'cprS) biofilms were modestly increased in 'htrA, and 'cprS enhanced biofilms were suppressed by Mg2+, suggesting dysregulation of envelope-related genes may underlie this phenotype. Thus, CprRS may regulate maintenance of the cell envelope, a structure that serves as the first line of interaction between pathogen and changing environments during pathogenesis.