CONSTRUCTION OF A STREPTOCOCCUS-PYOGENES RECA MUTANT VIA INSERTIONAL INACTIVATION, AND CLONING AND SEQUENCING OF THE COMPLETE RECA GENE

To facilitate future genetic studies with Streptococcus pyogenes (Sp), a recA mutant (Rec11) was constructed using a streptococcal integrati on vector carrying a PCR-derived internal recA fragment. The insertion of the plasmid in the mutant chromosome was identified by Southern hy bridization. Resistance to UV and the ability to accept linear DNA tra nsformation by Rec11 were greatly decreased, confirming its RecA pheno type. Using the PCR-derived fragment as a probe, we cloned and sequenc ed the complete Sp recA gene, which is highly homologous to the recA o f S. pneumoniae and Lactococcus lactis.