Cloning, characterization and expression of the recA gene of Aeromonas salmonicida

The Aeromonas salmonicida A449 recA gene has been cloned, sequenced and expressed in vitro. The predicted amino acid sequence of A. salmonicida RecA was determined and, when compared to other RecA, was found to possess a number of domains identical to those characterized in Escherichia coli RecA. The A. salmonicida recA was mobilized into an E. coli recA mutant strain and was shown to allow increased survival in the presence of the chemical mutagen MMS and after ultraviolet (UV) irradiation. The A. salmonicida recA also possesses a potential regulatory SOS box in the DNA 5' of the gene. The rate of A. salmonicida-mediated recombination in E. coli was increased by exposure to UV light, which suggests that SOS induction in A. salmonicida parallels that of E. coli.