title: Controlling gene expression in mycobacteria with anhydrotetracycline and Tet repressor.
abstract: Gene expression systems that allow the regulation of bacterial genes during an infection are valuable molecular tools but are lacking for mycobacterial pathogens. We report the development of mycobacterial gene regulation systems that allow controlling gene expression in fast and slow-growing mycobacteria, including Mycobacterium tuberculosis, using anhydrotetracycline (ATc) as inducer. The systems are based on the Escherichia coli Tn10-derived tet regulatory system and consist of a strong tet operator (tetO)-containing mycobacterial promoter, expression cassettes for the repressor TetR and the chemical inducer ATc. These systems allow gene regulation over two orders of magnitude in Mycobacterium smegmatis and M.tuberculosis. TetR-controlled gene expression was inducer concentration-dependent and maximal with ATc concentrations at least 10- and 20-fold below the minimal inhibitory concentration for M.smegmatis and M.tuberculosis, respectively. Using the essential mycobacterial gene ftsZ, we showed that these expression systems can be used to construct conditional knockouts and to analyze the function of essential mycobacterial genes. Finally, we demonstrated that these systems allow gene regulation in M.tuberculosis within the macrophage phagosome.
authors.affiliation: Department of Microbiology and Immunology, Weill Medical College of Cornell University New York, NY 10021, USA. sae2004@med.cornell.edu
authors.forename: Sabine
authors.initials: S
authors.lastname: Ehrt
authors.forename: Xinzheng V
authors.initials: XV
authors.lastname: Guo
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Hickey
authors.forename: Marvin
authors.initials: M
authors.lastname: Ryou
authors.forename: Mercedes
authors.initials: M
authors.lastname: Monteleone
authors.forename: Lee W
authors.initials: LW
authors.lastname: Riley
authors.forename: Dirk
authors.initials: D
authors.lastname: Schnappinger
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D003598:Cytoskeletal Proteins / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D015964:Gene Expression Regulation, Bacterial; D008264:Macrophages / Q000382:microbiology; D051379:Mice; D009161:Mycobacterium / Q000235:genetics*; D020102:Mycobacterium smegmatis / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000378:metabolism; D009875:Operator Regions, Genetic; D010588:Phagosomes / Q000382:microbiology; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000378:metabolism*; D013754:Tetracyclines / Q000494:pharmacology*
chemical_list: D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; C071525:FtsZ protein, Bacteria; D012097:Repressor Proteins; D013754:Tetracyclines; C034811:tetracycline resistance-encoding transposon repressor protein; C016229:4-epianhydrotetracycline