The Rho-independent transcription terminator for the porA gene enhances expression of the major outer membrane protein and Campylobacter jejuni virulence in abortion induction

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Dai, Lei
Wu, Zuowei
Xu, Changyun
Sahin, Orhan
Yaeger, Michael
Plummer, Paul
Zhang, Qijing
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Plummer, Paul
Associate Dean for Research and Graduate Studies
Zhang, Qijing
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Veterinary Pathology
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Veterinary Microbiology and Preventive Medicine
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Veterinary PathologyVeterinary Microbiology and Preventive MedicineVeterinary Diagnostic and Production Animal Medicine

Campylobacter jejuni is a leading cause of foodborne illnesses worldwide. Its porA gene encodes the major outer membrane protein (MOMP) that is abundantly expressed and has important physiological functions including a key role in systemic infection and abortion induction in pregnant animals. Despite the importance of porA in C. jejuni pathogenesis, mechanisms modulating its expression levels remain elusive. At the 3 prime end of the porA transcript, there is a Rho-independent transcription terminator (named TporA in this study). Whether TporA affects the expression and function of MOMP remains unknown and is investigated in this study. Green fluorescent protein (GFP) fusion constructs with the porA promoter at the 5 prime end and an intact TporA or no TporA at the 3 feet end of the gfp coding sequence revealed that both transcript level of gfp and its fluorescence signals were more than 2-fold higher in the construct with TporA than the one without TporA. qRT-PCR analysis of the porA mRNA and immunoblotting detection of the MOMP protein in C. jejuni showed that disruption of TporA significantly reduced the porA transcript level and expression of the MOMP protein. mRNA decay assay demonstrated that disruption of TporA resulted in shortened transcript half-life of the upstream gfp or porA genes, indicating TporA enhances mRNA stability. In the guinea pig model, the C. jejuni construct with an interrupted TporA was significantly attenuated in abortion induction. Together these results indicate that TporA enhances the expression level of MOMP by stabilizing its mRNA and influences the virulence of C. jejuni.


This is a manuscript of an article published as Dai, Lei, Zuowei Wu, Changyun Xu, Orhan Sahin, Michael Yaeger, Paul J. Plummer, and Qijing Zhang. "The Rho-independent transcription terminator for the porA gene enhances expression of the major outer membrane protein and Campylobacter jejuni virulence in abortion induction." Infection and Immunity 87, no. 12 (2019): e00687-19. DOI: 10.1128/IAI.00687-19. Posted with permission.

Tue Jan 01 00:00:00 UTC 2019