Conjugative Interaction Induces Transposition of IS Pst9 in Pseudomonas stutzeri AN10

• Published in: Journal of bacteriology 2009-02, Vol.191 (4), p.1239-1247
• Main Authors: Christie-Oleza, J. A., Lanfranconi, M. P., Nogales, B., Lalucat, J., Bosch, R.
• Format: Article
• Language: English
• ISSN: 0021-9193; 1098-5530
• DOI: 10.1128/JB.01071-08

IS Pst9 is an IS L3 -like insertion sequence (IS) that was recently described in the naphthalene-degrading organism Pseudomonas stutzeri strain AN10. In this paper we describe a novel strong IS regulation stimulus; transposition of IS Pst9 is induced in all P. stutzeri AN10 cells after conjugative interaction with Escherichia coli . Thus, we observed that in all P. stutzeri AN10 cells that received genetic material by conjugation the IS Pst9 genomic dose and/or distribution was changed. Furthermore, IS Pst9 transposition was also observed when P. stutzeri AN10 cells were put in contact with the plasmidless conjugative strain E. coli S17-1λ pir , but not when they were put in contact with E. coli DH5α (a nonconjugative strain). The mechanism of IS Pst9 transposition was analyzed, and transposition was shown to proceed by excision from the donor DNA using a conservative mechanism, which generated 3- to 10-bp deletions of the flanking DNA. Our results indicate that IS Pst9 transposes, forming double-stranded DNA circular intermediates consisting of the IS and a 5-bp intervening DNA sequence probably derived from the IS Pst9 flanking regions. The kinetics of IS circle formation are also described.