We found two Shiga toxin producing Escherichia coli O157:H7 strains isolated from humans carrying the stx1 gene with an IS1203-like element (designated as IS1203v1). The IS1203v1 was inserted into the coding region of the A subunit 7 bp upstream from the TGA termination codon, resulting in a loss of two amino acid residues (Ser-Ser) from its C terminus. Toxicity of the Stx1 was confirmed by Vero cell assay. IS1203v1 hardly affected the stx1 gene in either its expression or the toxicity of its product.
All Science Journal Classification (ASJC) codes
- Molecular Biology