title: Molecular analysis of an extrachromosomal element containing the C2 toxin gene discovered in Clostridium botulinum type C.
abstract: Clostridium botulinum cultures are classified into seven types, types A to G, based on the antigenicity of the neurotoxins produced. Of these seven types, only types C and D produce C2 toxin in addition to the neurotoxin. The C2 toxin consists of two components designated C2I and C2II. The genes encoding the C2 toxin components have been cloned, and it has been stated that they might be on the cell chromosome. The present study confirmed by using pulsed-field gel electrophoresis and subsequent Southern hybridization that these genes are on a large plasmid. The complete nucleotide sequence of this plasmid was determined by using a combination of inverse PCR and primer walking. The sequence was 106,981 bp long and contained 123 potential open reading frames, including the c2I and c2II genes. The 57 products of these open reading frames had sequences similar to those of well-known proteins. It was speculated that 9 these 57 gene products were related to DNA replication, 2 were responsible for the two-component regulatory system, and 3 were sigma factors. In addition, a total of 20 genes encoding proteins related to diverse processes in purine catabolism were found in two regions. In these regions, there were 9 and 11 genes rarely found in plasmids, indicating that this plasmid plays an important role in purine catabolism, as well as in C2 toxin production.
authors.affiliation: Department of Bacteriology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Okayama 700-8558, Japan.
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Sakaguchi
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Hayashi
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Keisuke
authors.initials: K
authors.lastname: Nakayama
authors.forename: Kai
authors.initials: K
authors.lastname: Zhang
authors.forename: Shaobo
authors.initials: S
authors.lastname: Ma
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Arimitsu
authors.forename: Keiji
authors.initials: K
authors.lastname: Oguma
mesh_terms: D001483:Base Sequence; D015139:Blotting, Southern; D001905:Botulinum Toxins / Q000235:genetics*; D003014:Clostridium botulinum / Q000235:genetics*; D047968:Clostridium botulinum type C / Q000235:genetics; D047969:Clostridium botulinum type D / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D010802:Phylogeny; D010957:Plasmids / Q000235:genetics*; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
chemical_list: D001905:Botulinum Toxins