The effect of dam methylation on Tn5 transposition was investigated by analyses of mutations in the host (Escherichia coli) and the element. Wild-type elements transposed at a higher frequency and showed higher levels of transposase expression in a dam-host. Mutations were made in the promoter region of the transcript that codes for the transposase. Transposition and transposase levels from the...

The end sequences of the IS50 insertion sequence are known as the outside end (OE) and inside end. These complex ends are related but nonidentical 19-bp sequences that serve as substrates for the activity of the Tn5 transposase. Besides providing the binding site of the transposase, the end sequences of a transposon contain additional types of information necessary for transposition. These addi...