Transposition of IS1181 in the genomes of Staphylococcus and Listeria

The recombinant plasmid pIP1713 was constructed to analyse the transpositio nal activity of the insertion sequence IS1181 in Staphylococcus aureus RN42 20, Staphylococcus carnosus TM300 and Listeria monocytogenes EGD. This 11.3 -kb plasmid contains two genetically different elements: (i) a pE194ts-deri ved replicon, the ermC gene of which confers resistance to erythromycin in Gram-positive bacteria of several species, and (ii) a copy of IS1181, clone d from S. aureus BM3121, in which the tetracycline resistance gene, tet(T), has been inserted between the transposase-encoded gene and the downstream inverted repeat. When introduced by electroporation into the three bacteria l hosts, pIP1713 delivered IS1181 Omega tet(T) to various chromosomal sites . Cointegrate structures between pIP1713 and the host chromosome were occas ionally detected. Transposition was associated with 8-bp repeats at the ins ertion sites. IS1181 Omega tet(T) could be used for random mutagenesis in G ram-positive bacteria. (C) 1999 Federation of European Microbiological Soci eties. Published by Elsevier Science B.V. All rights reserved.