Isolation of a new insertion element of Yersinia intermedia closely related to remnants of mobile genetic elements present on Yersinia plasmids harboring the Yop virulon

A new insertion element present in two alleles, designated IS1635.1 and IS1 635.2, was identified on a plasmid of a Yersinia intermedia strain by hybri dization with the Yersinia enterocolitica pYV virulence plasmid. IS1635.1 a nd IS1635.2 are 861 bp long, carry imperfect inverted terminal repeats and possess a single open reading frame encoding a putative transposase of the IS6 family. A truncated IS1635 element is present immediately downstream of element IS1635.2. The capacity of the IS1635 elements to mediate transposi tion in Yersinia was demonstrated with a R6K-derived suicide vector, where a kanamycin resistance gene had been inserted between IS1635.1 and IS1635.2 . Hybridization and sequence alignments showed that remnants of IS1635-like insertion elements harboring large deletions and point mutations are prese nt on the Yop virulon harboring plasmids of pathogenic Yersinia strains. In a few cases, the IS1635 element has also been found on plasmids of apathog enic Yersinia strains. (C) 2000 Federation of European Microbiological Soci eties. Published by Elsevier Science B.V. All rights reserved.