A native plasmid of Streptococcus suis DAT1, pSSU1, was used to construct pDAT series shuttle vectors. In addition to the replication function of pSSU1, these vectors contain the multiple cloning sites and lacZ' gene from pUC19, which means that X-gal screening can be used to select recombinants in Escherichia coli. pDAT1, pDAT2, and pDAT3 carry cat, spc, and both genes as selectable markers, respectively. These vectors can be introduced into S. suis, E. coli, Salmonella typhimurium, Streptococcus pneumoniae, and Streptococcus equi subsp. equi by electroporation. The recA gene was cloned from S. suis and sequenced. Then, an S. suis recA mutant strain was constructed via homologous recombination. Furthermore, cloning of a functional S. suis recA gene into pDAT2 and complementation analysis of the recA mutant were successful in S. suis, but not in E. coli. These results show that pDAT vectors are useful tools for cloning and analyzing S. suis genes in S. suis strains directly. (Molecular Bacteriology Section, Department of Infectious Diseases, TEL +81-298-38-7743)
References:
1. Takamatsu, D. et al.: Sequence analysis of a small cryptic plasmid isolated from Streptococcus suis serotype 2. Curr. Microbiol., 40 : 61-66 (2000)
2. Takamatsu, D. et al.: Construction and characterization of Streptococcus suis-Escherichia coli shuttle cloning vectors. Plasmid., 45 : 101-113 (2001)
