title: The role of regulator Eha in Edwardsiella tarda pathogenesis and virulence gene transcription.
abstract: Edwardsiella tarda is a pathogen with a broad host range that infects both animals and humans. Eha is a new transcriptional regulator identified in ET13, which is involved in the bacterial hemolytic activity. This study explored the effect of the Eha in the pathogenesis of E. tarda and the transcriptional regulation of the bacterial virulence genes (eseC, fliC, pagC and fimA). Our results found that the virulence of the eha mutant was 2.5-fold less than the one of its wild ET13 by LD50 in a murine model of i.p. infection, and the bacterial loads of the mutant displayed a different profile from the one of the wild strain. Most significantly, the mice infected with the mutant have greatly reduced acute inflammation in the liver, spleen and kidney compared to the ones infected with the wild. We further demonstrated that eseC, fliC and pagC were regulated directly by the Eha with qRT-PCR and β-Galactosidase assay, but fimA wasn't done. The promoter regions of the genes modulated and the cly gene reported before had been found to contain a common conserved motif by using software. In addition, we found that the wild strain was more toxic to RAW264.7 macrophages, and induced less the host cell apoptotic responses than the eha mutant did. Altogether, these data suggested that the Eha was required for the bacterial infection and the transcriptive regulation of the important virulence genes of E. tarda.
authors.affiliation: Department of Pathogenic Microbiology and Immunology, Southeast University School of Medicine, China. Electronic address: dgao2@seu.edu.cn.
authors.forename: Daqing
authors.initials: D
authors.lastname: Gao
authors.affiliation: Department of Pathogenic Microbiology and Immunology, Southeast University School of Medicine, China.
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Li
authors.affiliation: JiangSu University School of Medicine, China.
authors.forename: Zeyan
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Department of Pathogenic Microbiology and Immunology, Southeast University School of Medicine, China.
authors.forename: Ankang
authors.initials: A
authors.lastname: Sheng
authors.affiliation: Department of Pathogenic Microbiology and Immunology, Southeast University School of Medicine, China.
authors.forename: Enjin
authors.initials: E
authors.lastname: Zheng
authors.affiliation: Department of Clinical Lab, Southeast University School of Medicine, China.
authors.forename: Zeye
authors.initials: Z
authors.lastname: Shao
authors.affiliation: Department of Pathogenic Microbiology and Immunology, Southeast University School of Medicine, China.
authors.forename: Nian
authors.initials: N
authors.lastname: Liu
authors.affiliation: College of Veterinary Medicine, NanJing Agricultural University, China.
authors.forename: Chengping
authors.initials: C
authors.lastname: Lu
mesh_terms: D000818:Animals; D058491:Bacterial Load; D002470:Cell Survival; D004195:Disease Models, Animal; D020609:Edwardsiella tarda / Q000235:genetics* / Q000472:pathogenicity*; D004756:Enterobacteriaceae Infections / Q000382:microbiology / Q000473:pathology; D055786:Gene Knockout Techniques; D005809:Genes, Regulator; D007668:Kidney / Q000473:pathology; D007928:Lethal Dose 50; D008099:Liver / Q000473:pathology; D008264:Macrophages / Q000382:microbiology / Q000502:physiology; D051379:Mice; D013154:Spleen / Q000473:pathology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D014774:Virulence; D037521:Virulence Factors / Q000096:biosynthesis*
chemical_list: D014157:Transcription Factors; D037521:Virulence Factors
keywords: Edwardsiella tarda; Regulator; Virulence; eha gene