Cold shock exoribonuclease R (VacB) is involved in Aeromonas hydrophila pathogenesis

Tatiana E. Erova, Valeri G. Kosykh, Amin A. Fadl, Jian Sha, Amy J. Horneman, Ashok K. Chopra

Research output: Contribution to journalArticlepeer-review

47 Scopus citations


In this study, we cloned and sequenced a virulence-associated gene (vacB) from a clinical isolate SSU of Aeromonas hydrophila. We identified this gene based on our recently annotated genome sequence of the environmental isolate ATCC 7966T of A hydrophila and the vacB gene of Shigella flexneri. The A. hydrophila VacB protein contained 798 amino acid residues, had a molecular mass of 90.5 kDa, and exhibited an exoribonuclease (RNase R) activity. The RNase R of A. hydrophila was a cold-shock protein and was required for bacterial growth at low temperature. The vacB isogenic mutant, which we developed by homologous recombination using marker exchange mutagenesis, was unable to grow at 4°C. In contrast, the wild-type (WT) A. hydrophila exhibited significant growth at this low temperature. Importantly, the vacB mutant was not defective in growth at 37°. The vacB mutant also exhibited reduced motility, and these growth and motility phenotype defects were restored after complementation of the vacB mutant. The A. hydrophila RNase R-lacking strain was found to be less virulent in a mouse lethality model (70% survival) when given by the intraperitoneal route at as two 50% lethal doses (LD 50). On the other hand, the WT and complemented strains of A. hydrophila caused 80 to 90% of the mice to succumb to infection at the same LD50 dose. Overall, this is the first report demonstrating the role of RNase R in modulating the expression of A. hydrophila virulence.

Original languageEnglish (US)
Pages (from-to)3467-3474
Number of pages8
JournalJournal of bacteriology
Issue number10
StatePublished - May 2008

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology


Dive into the research topics of 'Cold shock exoribonuclease R (VacB) is involved in Aeromonas hydrophila pathogenesis'. Together they form a unique fingerprint.

Cite this