Genetic organization of insertion element IS 2 based on a revised nucleotide sequence : Short communication

Abstract

We identified a transposable element resident in the chromosome of Escherichia coli K-12 strain HB101. This is an approx. 4400-bp-long transposon flanked by two copies of insertion sequence (IS) 1 element in direct orientation. One of the IS 1 elements was found to be integrated into an IS 2 element between IS 2 bp 139 and bp 140 with the large moiety of IS 2 within the transposon. The sequence of this part of IS2 differs from the published sequence of galOP-308::IS 2 at a number of positions. Restriction analysis of the published allele, however, indicated that both alleles may in fact be identical. Since six of the eight differences found alter open reading frames, the revised sequence presents a new outlook for the potential genetic organization of IS 2.