title: Molecular characterization of the clusters of genes encoding the botulinum neurotoxin complex in clostridium botulinum (Clostridium argentinense) type G and nonproteolytic Clostridium botulinum type B.
abstract: The cluster of genes encoding components of the progenitor botulinum neurotoxin complex has been mapped and cloned in Clostridium botulinum type G strain ATCC 27322. Determination of the nucleotide sequence of the region has revealed open reading frames encoding nontoxic components of the complex, upstream of the gene encoding BoNT/G (botG). The arrangement of these genes differs from that in strains of other antigenic toxin types. Immediately upstream of botG lies a gene encoding a protein of 1198 amino acids, which shows homology with the nontoxic-nonhemagglutinin (NTNH) component of the progenitor complex. Further upstream there are genes encoding proteins with homology to hemagglutinin components (HA-17, HA-70) and a putative positive regulator of gene expression (P-21). Sequence comparison has shown that BoNT/G has highest homology with BoNT/B. The sequence of the BoNT-cluster of genes in non-proteolytic C. botulinum type B strain Eklund 17B has been extended to include the complete NTNH and HA-17, and partial HA-70 gene sequences. Comparison of NTNH/G with other NTNHs reveals that it shows highest homology with NTNH/B consistent with the genealogical affinity shown between BoNT/G and BoNT/B genes.
authors.affiliation: Department of Microbiology, Institute of Food Research, Earley Gate, Whiteknights Road, Reading, RG6 6BZ, UK.
authors.forename: M
authors.initials: M
authors.lastname: Bhandari
authors.forename: K D
authors.initials: KD
authors.lastname: Campbell
authors.forename: M D
authors.initials: MD
authors.lastname: Collins
authors.forename: A K
authors.initials: AK
authors.lastname: East
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001905:Botulinum Toxins / Q000235:genetics*; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D003014:Clostridium botulinum / Q000145:classification / Q000235:genetics*; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D019143:Evolution, Molecular; D005798:Genes, Bacterial; D006388:Hemagglutinins / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family; D016133:Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid
chemical_list: D017931:DNA Primers; D004269:DNA, Bacterial; D006388:Hemagglutinins; D001905:Botulinum Toxins