Nucleotide sequence analysis of IS427 and its target sites inAgrobacterium tumefaciens T37

We have determined the nucleotide sequence of IS427, an insertion sequence fromAgrobacterium tumefaciens T37. IS427 is 1271 bp long, contains 16-bp imperfect terminal inverted repeats, and generates a 2-bp target sequence duplication. It is present at three sites in the pTiT37 plasmid and is absent from the chromosome ofA. tumefaciens T37. Each of the IS427 elements sequenced was near a site with sequence homology to integration host factor (IHF)-binding sites which suggested that IHF may be involved in IS427 transposition.