High-throughput PCR screening of genes for three-component regulatory system putatively involved in quorum sensing from low-G+C gram-positive bacteria

Quorum sensing of Gram-positive bacteria is often regulated by three-component regulatory system composed of autoinducing peptide, sensor kinase and response regulator. We used PCR to study a gene cassette encoding this three-component regulatory system. Degenerate primers were designed from consensus amino acid sequences in the HPK₁₀ subfamily, mostly involved in quorum sensing. Products amplified from genomic DNA of Lactobacillus, Enterococcus, and Clostridium species were cloned and sequenced; their deduced amino acid sequences were similar to those of members of the HPK₁₀ subfamily. Complete genes for the putative gene cassette were cloned by inverse PCR from L. paracasei E93490 and L. plantarum WCFS6. Phylogenetic analysis grouped the cloned putative HPKs into the HPK₁₀ subfamily. These results indicated the usefulness of this high-throughput gene screening and suggested that the three-component regulatory gene cassette are widely present.