title: Regulation of toxin gene expression in Clostridium perfringens.
abstract: The Gram-positive, anaerobic, spore-forming, rod-shaped Clostridium perfringens is widely distributed in nature, especially in soil and the gastrointestinal tract of humans and animals. C. perfringens causes clostridial myonecrosis (or gas gangrene), enteritis and enterotoxemia in humans and livestock by producing numerous extracellular toxins and enzymes. The toxin gene expression is regulated by a two-component regulatory system and regulatory RNA VirR/VirS-VR-RNA cascade. The VirR/VirS system was originally found in a type A strain, but a recent report showed that it is also important for the toxin gene regulation in other types of strains. Two types of cell-cell signaling, i.e., agr-system and AI-2 signaling, are also important for the regulation of toxin genes. Several regulatory systems independent from the VirR/VirS system, including virX, the orphan histidine kinase ReeS and orphan response regulator RevR, are also involved in the regulation of toxin genes. In addition, the expression of toxin genes is upregulated after contact with Caco-2 cells. C. perfringens has a complex regulatory network for toxin gene expression and thus the coordination of toxin gene expression is important for the process of infection.
authors.affiliation: Department of Bacteriology, Graduate School of Medical Science, University of Kanazawa, 13-1 Takara-Machi, Kanazawa, Ishikawa 920-8640, Japan. Electronic address: ohtanik@med.kanazawa-u.ac.jp.
authors.forename: Kaori
authors.initials: K
authors.lastname: Ohtani
authors.affiliation: Department of Bacteriology, Graduate School of Medical Science, University of Kanazawa, 13-1 Takara-Machi, Kanazawa, Ishikawa 920-8640, Japan.
authors.forename: Tohru
authors.initials: T
authors.lastname: Shimizu
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000096:biosynthesis* / Q000235:genetics; D018938:Caco-2 Cells; D003015:Clostridium Infections / Q000382:microbiology / Q000662:veterinary; D003016:Clostridium perfringens / Q000235:genetics*; D004847:Epithelial Cells / Q000382:microbiology; D015964:Gene Expression Regulation, Bacterial; D053263:Gene Regulatory Networks; D006801:Humans; D008954:Models, Biological; D015398:Signal Transduction; D037521:Virulence Factors / Q000096:biosynthesis / Q000235:genetics
chemical_list: D001427:Bacterial Toxins; D037521:Virulence Factors
keywords: Cell–cell signaling; Cell–pathogen signaling; Regulatory RNA; Substance A; Two-component system