The staphylococcal β-lactamase (Bla) transposon Tn4002 has previously been reported to have a high level of insertional specificity for a 1.8-kb region on the plasmid pSK1. Nucleotide sequences of this region and of a related region on plasmid pl9789 were determined. Sequence analysis revealed that these two plasmids contain sin, a gene whose deduced product shows similarity to a family of DNA recombinases. Southern hybridisation analysis indicated that sin is located on α-, β- and γ-families of Bla plasmids and on pSK1 family plasmids. A region of dyad symmetry located upstream from sin on pSK1 and pI9789 was identified as the site of insertions of Tn552 and Tn4002 in separate isolates.
- transposon insertions
- β-lactamase transposons