Identification of the streptococcal competence‐pheromone receptor

作者：Leiv Sigve Håvarstein, Peter Gaustad, Ingolf Figved Nes, Donald A. Morrison · 发表于：Molecular Microbiology · 年份：1996 · DOI：10.1046/j.1365-2958.1996.521416.x · 被引用次数：291 · 研究领域：Bacterial Infections and Vaccines、Streptococcal Infections and Treatments、Antimicrobial Resistance in Staphylococcus

Competence for genetic transformation in certain species of streptococci has been known for many years to be induced by a secreted protease-sensitive pheromone, referred to as the competence factor or activator, which acts as a quorum-sensing signal to co-ordinate expression of late competence genes. We recently reported identification of the pheromone of Streptococcus pneumoniae strain Rx as a small unmodified peptide, which was termed competence-stimulating peptide (CSP). By identifying the gene (comC) encoding the Rx CSP we were able to show that it is synthesized as a precursor peptide containing an N-terminal double-glycine type leader. In the present work, we describe two alleles of the corresponding gene from Streptococcus gordonii strains Challis and NCTC 7865, which are strains with distinct competence pheromones and corresponding specific pheromone reactivities. In addition, the nucleic acid sequences of two genes located downstream of comC were determined; interestingly, these genes encode a two-component signal transduction system. We therefore speculated that their products, a histidine kinase (ComD) and its cognate response regulator (ComE), act downstream of the CSP in competence regulation. By tracing the CSP specificity of the competence response in these strains to strain-specific alleles of comD, we obtained evidence demonstrating that the histidine kinase ComD is the competence-pheromone receptor.