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.
Department of Food Microbiology and Toxicology, Food Research Institute, University of Wisconsin, 1925 Willow Drive, Madison, WI 53706, USA.
Sean S
SS
Dineen
Marite
M
Bradshaw
Eric A
EA
Johnson
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