Open AccessMolecular Analysis of an Extrachromosomal Element Containing the C2 Toxin Gene Discovered in Clostridium botulinum Type C
Author(s) -
Yoshihiko Sakaguchi,
Tetsuya Hayashi,
Yumiko Yamamoto,
Keisuke Nakayama,
Kai Zhang,
Edmond S.K.,
Hideyuki Arimitsu,
Keiji Oguma
Publication year - 2009
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.01797-08
Subject(s) - biology , plasmid , extrachromosomal dna , gene , open reading frame , genetics , clostridium botulinum , nucleic acid sequence , toxin , clostridium , gene cluster , microbiology and biotechnology , peptide sequence , bacteria
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 thec2I andc2II 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 σ 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.