IS1491 FROM PSEUDOMONAS-ALCALIGENES NCIB-9867 - CHARACTERIZATION AND DISTRIBUTION AMONG PSEUDOMONAS SPECIES

A new insertion sequence, IS1491, has been cloned and sequenced. The 2 489-bp IS1491 was isolated from a Pseudomonas alcaligenes NCIB 9867 (s train P25X) 4.8-kb PstI chromosomal fragment. IS1491 is flanked by an imperfect inverted repeat of 23 bp and carries two overlapping open re ading frames, ORF1 and ORF2. Both ORF1 and ORF2 displayed homology to the IstA-like and IstB-like transposases encoded by the IS21 family of insertion sequences, which include two IS elements previously isolate d from P. alcaligenes P25X, IS1474, and IS1475 (Yeo, C. C., and Poh, C . L. (1997). FEMS Microbiol. Lett. 149, 257-263). Transposition assays showed that IS1491 transposed at a frequency of approximately 1.4 x 1 0(-6). Transposition of IS1491 into the target pRK4I5 replicon was obs erved but when ORF2 was disrupted, a fusion between the donor and targ et replicons was detected. IS1491-like sequences were detected in tota l DNA of Pseudomonas putida NCIB 9869 (strain P35X), Pseudomonas aerug inosa, Pseudomonas stutzeri, Pseudomonas syringae, Pseudomonas mendoci na, Comomonas acidovorans, and Comomonas testosteroni by hybridization with IS1491 DNA. (C) 1998 Academic Press.