title: Vibrio parahaemolyticus CalR down regulates the thermostable direct hemolysin (TDH) gene transcription and thereby inhibits hemolytic activity.
abstract: TDH, encoded by tdh gene, is a major virulent determinant of V. parahaemolyticus that controls various biological activities, such as hemolytic activity, cytotoxicity, and enterotoxicity. The hemolytic activity on Wagatsuma agar ascribed to TDH is called Kanagawa phenomenon (KP). All KP positive strains contain tdh1 and tdh2 genes, but tdh2 is predominantly responsible for KP. CalR is a regulatory protein that was originally identified as a repressor of swarming motility and T3SS1 gene expression in V. parahaemolyticus. In the present study, the regulation of tdh2 by CalR was investigated using a set of experiments including qRT-PCR, primer extension, LacZ fusion, hemolytic phenotype, EMSA, and DNase I footprinting assays. The results showed that His-CalR protected a single region from 224bp to 318bp upstream of tdh2 against DNase I digestion, and a transcriptional start site located at 42bp upstream of tdh2 was detected and its transcribed activity was inhibited by CalR. Moreover, the KP test results showed that the hemolytic activity of V. parahaemolyticus is also under negative control of CalR. The data demonstrated that CalR is a repressor of the tdh2 transcription and thereby inhibits the hemolytic activity of V. parahaemolyticus.
authors.affiliation: School of Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, China.
authors.forename: Yiquan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: School of Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Centre for Disease Control and Prevention, Beijing 102206, China.
authors.forename: He
authors.initials: H
authors.lastname: Gao
authors.affiliation: School of Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, China.
authors.forename: Lingyu
authors.initials: L
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Yin
authors.affiliation: School of Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, China.
authors.forename: Xinxiang
authors.initials: X
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
authors.forename: Huiying
authors.initials: H
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China. Electronic address: fionyoung@163.com.
authors.forename: Wenhui
authors.initials: W
authors.lastname: Yang
authors.affiliation: Department of Clinical Laboratory, the First Hospital Affiliated to Henan University, Kaifeng 475000, Henan, China. Electronic address: wangli851217@163.com.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
mesh_terms: D001427:Bacterial Toxins / Q000235:genetics; D004912:Erythrocytes / Q000382:microbiology; D024581:Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating) / Q000235:genetics; D006460:Hemolysin Proteins / Q000235:genetics*; D006801:Humans; D011401:Promoter Regions, Genetic; D014158:Transcription, Genetic; D014735:Vibrio Infections / Q000382:microbiology*; D014736:Vibrio parahaemolyticus / Q000235:genetics* / Q000472:pathogenicity
chemical_list: D001427:Bacterial Toxins; D006460:Hemolysin Proteins; C068489:thermostable direct hemolysin; D024581:Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating)
keywords: CalR; Kanagawa phenomenon; Vibrio parahaemolyticus; tdh2