Novel tetracycline inducible regulation systems for staphylococci

• Applicant: Privatdozent Dr. Ralph Alexander Bertram
• Subject Area: Parasitology and Biology of Tropical Infectious Disease Pathogens
• Term: from 2007 to 2011
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 47284589

Inducible gene-expression tools are indispensable for bacterial genetics. One popular and potent system, based on the tetracycline (tc) represser TetR, is known as tef-regulation. There, TetR regulates transcriptional initiation at tc-sensitive promoters, i.e. those with tef-operator sequences. The aim of this project is to establish and apply an efficient tef-regulation system in Staphylococcus aureus, a pathogenic bacterium responsible for severe diseases and nosocomial infections. To this end, we will develop efficient set-ups for tef-regulation based upon our experiences in the model organism Bacillus subtilis. There, efficient regulation of a single copy target gene is possible with tetR encoded either on a plasmid or in the chromosome. After adaptation of the tools to S. aureus, we will place genes of interest under tef-control by exchanging the original promoter for a tc-sensitive one. This will be achieved either in the genes' natural loci or in an easily accessible phage attachment site. For random integration of tc-sensitive promoters into the genome, in order to reveal unknown genes' functions, we will exploit transposon-like elements, which we also have established for B. subtilis. Furthermore, we plan to establish a Cre/loxP site specific recombination system for S. aureus that will be helpful for eliminating antibiotic resistance markers. With these tools at hand and with the results obtained through dosed expression of target genes, their function can be better studied and new questions in staphylococcal genetics can be addressed leading to a deeper understanding of this pathogen.

• DFG Programme: Research Grants