Edwardsiella tarda DnaJ is a virulence-associated molecular chaperone with immunoprotective potential

Fish Shellfish Immunol. 2011 Aug;31(2):182-8. doi: 10.1016/j.fsi.2011.05.001. Epub 2011 May 14.


Members of the DnaJ/Hsp40 family play an important role in protein homeostasis by regulating the activity of DnaK/Hsp70. In this study, we examined the activity and function of the DnaJ from Edwardsiella tarda, a serious fish pathogen that can also infect humans and birds. In silico analysis indicated that E. tarda DnaJ contains structural features, i.e. the J domain, the glycine/phenylalanine-rich region, and the zinc-finger domain, that are conserved among Type I Hsp40. Purified recombinant DnaJ was able to stimulate the ATPase activity of DnaK. Pull-down assay indicated that DnaJ could interact specifically with DnaK. Mutation of the conserved HPD site in the J domain completely abolished the DnaK-stimulating effect of DnaJ. To examine the functional importance of DnaJ, a dnaJ-defective mutant was constructed. Compared to the wild type, the dnaJ mutant (i) was retarded in growth and more sensitive to H₂O₂-induced oxidative damage, (ii) dramatically reduced in general bacterial virulence and in blood dissemination capacity, and (iii) significantly weakened in the ability to block macrophage activation and to survive within macrophages. Furthermore, when used as a subunit vaccine, purified recombinant DnaJ induced protective immunity in Japanese flounder (Paralichthys olivaceus). Taken together, these results indicate that DnaJ plays an important role in the pathogenesis of E. tarda probably by functioning as a DnaK partner and that DnaJ, with its immunoprotective property, may be useful in the control of E. tarda infection in aquaculture.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Bacterial Vaccines / genetics
  • Bacterial Vaccines / immunology
  • Cloning, Molecular
  • DNA, Bacterial / genetics
  • DNA, Bacterial / immunology*
  • DNA, Bacterial / metabolism
  • Edwardsiella tarda / genetics
  • Edwardsiella tarda / metabolism*
  • Edwardsiella tarda / pathogenicity*
  • Enterobacteriaceae Infections / immunology
  • Enterobacteriaceae Infections / microbiology
  • Enterobacteriaceae Infections / prevention & control
  • Enterobacteriaceae Infections / veterinary*
  • Fish Diseases / immunology
  • Fish Diseases / microbiology
  • Fish Diseases / prevention & control
  • Flounder / microbiology*
  • HSP40 Heat-Shock Proteins / genetics
  • HSP40 Heat-Shock Proteins / metabolism*
  • HSP70 Heat-Shock Proteins / genetics
  • HSP70 Heat-Shock Proteins / metabolism
  • Molecular Chaperones / genetics
  • Molecular Chaperones / metabolism
  • Molecular Sequence Data
  • Oxidation-Reduction
  • Polymerase Chain Reaction / veterinary
  • Recombinant Proteins / genetics
  • Recombinant Proteins / immunology
  • Sequence Analysis, DNA
  • Vaccines, Subunit / immunology
  • Virulence


  • Bacterial Vaccines
  • DNA, Bacterial
  • HSP40 Heat-Shock Proteins
  • HSP70 Heat-Shock Proteins
  • Molecular Chaperones
  • Recombinant Proteins
  • Vaccines, Subunit