Neurotoxin gene clusters in Clostridium botulinum type A strains: sequence comparison and evolutionary implications.
The nucleotide sequence of the hemagglutinin ( ha) genes and the transcriptional regulator botR gene were determined in type A Clostridium botulinum strain 62A, and the complete nucleotide sequence of the botulinum neurotoxin (BoNT) gene cluster was determined in strain Hall A- hyper. Comparison of the BoNT/A gene clusters revealed only two nucleotide differences between the two strains. The nucleotide sequences of the regions flanking the BoNT clusters were also determined in strains 62A, Hall A- hyper, and type A(B) strain NCTC 2916. The regions upstream of the BoNT/A clusters in the type A strains shared marked homology with the region upstream of the silent BoNT/B cluster in the A(B) strain, indicating a similar evolutionary origin. The region downstream of the BoNT/A cluster in type A strains encodes putative insertion sequence (IS) elements with multiple internal mutations. These IS elements may have played a role in neurotoxin gene transfer within the host genome and to other Clostridium species.
Dineen
Sean S
SS
Department of Food Microbiology and Toxicology, Food Research Institute, University of Wisconsin, 1925 Willow Drive, Madison, WI 53706, USA.
Bradshaw
Marite
M
Johnson
Eric A
EA
D001905:Botulinum Toxins / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D003014:Clostridium botulinum / Q000235:genetics* / Q000378:metabolism; D019143:Evolution, Molecular; D006388:Hemagglutinins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D005810:Multigene Family; D009498:Neurotoxins / Q000235:genetics*; D017422:Sequence Analysis, DNA
D006388:Hemagglutinins; D009498:Neurotoxins; D001905:Botulinum Toxins