title: Complex transcriptional regulation of citrate metabolism in Clostridium perfringens.
abstract: A Gram-positive, spore-forming bacterium, Clostridium perfringens, possesses genes for citrate metabolism, which might play an important role in the utilization of citrate as a sole carbon source. In this study, we identified a chromosomal citCDEFX-mae-citS operon in C. perfringens strain 13, which is transcribed on three mRNAs of different sizes. Expression of the cit operon was significantly induced when 5 mM extracellular citrate was added to the growth medium. Most interestingly, three regulatory systems were found to be involved in the regulation of the expression of cit genes: 1) the two upstream divergent genes citG and citI; 2) two different two-component regulatory systems, CitA/CitB (TCS6 consisted of CPE0531/CPE0532) and TCS5 (CPE0518/CPE0519); and 3) the global two-component VirR/VirS-VR-RNA regulatory system known to regulate various genes for toxins and degradative enzymes. Our results suggest that in C. perfringens the citrate metabolism might be strictly controlled by a complex regulatory system.
authors.affiliation: Department of Bacteriology, Graduate School of Medical Science, Kanazawa University, 13-1, Takara-machi, Kanazawa 920-8640, Japan.
authors.forename: Yonghui
authors.initials: Y
authors.lastname: Yuan
authors.forename: Kaori
authors.initials: K
authors.lastname: Ohtani
authors.forename: Satoko
authors.initials: S
authors.lastname: Yoshizawa
authors.forename: Tohru
authors.initials: T
authors.lastname: Shimizu
mesh_terms: D019343:Citric Acid / Q000378:metabolism* / Q000494:pharmacology; D003016:Clostridium perfringens / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D023061:Gene Order; D005822:Genetic Vectors; D053858:Metabolic Networks and Pathways / Q000235:genetics; D009154:Mutation; D009876:Operon / Q000187:drug effects; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D019343:Citric Acid