Cloning of recA Gene and Its Biological Function in λ Lysogenic Bacteria

With a pair of primers and the E. coli chromosome DNA as the template, an intact recA gene was obtained by PCR. The recombinant plasmid was constructed by ligating the PCR product and pUC18 in vitro and then transformed into E. coli DH5α and E. coli k12(λ+), respectively. The plasmid pUR4 containing the recA gene has been screened. The biological function of recA gene in different strains was determined with or without UV induction. The results indicated that the recA gene showed a remarkable physiological function in the λ lysogenic bacteria. It could induce the λ prophage to enter the lysis cycle from lysogenic state. This recombinant plasmid will be a useful tool in the studies of the inductive mechanism of λ prophage and the repair of cells damaged by UV-irradiation.