Identification and functional analysis of two toxin-antitoxin systems in Campylobacter jejuni.
Toxin-antitoxin (TA) systems are widely distributed in bacteria and play an important role in maintaining plasmid stability. The leading foodborne pathogen, Campylobacter jejuni, can carry multiple plasmids associated with antibiotic resistance or virulence. Previously a virulence plasmid named pVir was identified in C. jejuni 81-176 and IA3902, but determining the role of pVir in pathogenesis has been hampered because the plasmid cannot be cured. In this study, we report the identification of two TA systems that are located on the pVir plasmid in 81-176 and IA3902, respectively. The virA (proteic antitoxin)/virT (proteic toxin) pair in IA3902 belongs to a Type II TA system, while the cjrA (RNA antitoxin)/cjpT (proteic toxin) pair in 81-176 belongs to a Type I TA system. Notably, cjrA (antitoxin) represents the first noncoding small RNA demonstrated to play a functional role in Campylobacter physiology to date. By inactivating the TA systems, pVir was readily cured from Campylobacter, indicating their functionality in Campylobacter. Using pVir-cured IA3902, we demonstrated that pVir is not required for abortion induction in the guinea pig model. These findings establish the key role of the TA systems in maintaining plasmid stability and provide a means to evaluate the function of pVir in Campylobacter pathobiology.
Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, 50011, USA.
Zhangqi
Z
Shen
Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, 50011, USA.
Rocky D
RD
Patil
Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, 50011, USA.|Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA, 50011, USA.
Orhan
O
Sahin
Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, 50011, USA.
Zuowei
Z
Wu
Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, 50011, USA.|Microbiology Laboratory, Hangzhou Center for Disease Control and Prevention, Hangzhou, Zhejiang, 310021, China.
Xiao-Ying
XY
Pu
Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, 50011, USA.
Lei
L
Dai
Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, 50011, USA.|Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA, 50011, USA.
Paul J
PJ
Plummer
Department of Veterinary Pathology, Iowa State University, Ames, IA, 50011, USA.
Michael J
MJ
Yaeger
Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, 50011, USA. zhang123@iastate.edu.
Qijing
Q
Zhang
D000818:Animals; D000992:Antitoxins / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001427:Bacterial Toxins / Q000235:genetics / Q000378:metabolism*; D002169:Campylobacter Infections / Q000382:microbiology; D016123:Campylobacter jejuni / Q000235:genetics / Q000378:metabolism*; D002876:Chromosomes, Bacterial; D004195:Disease Models, Animal; D006168:Guinea Pigs; D010957:Plasmids / Q000235:genetics
D000992:Antitoxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins