Local hopping of IS3 elements into the A+T-rich part of the high-pathogenicity island in Yersinia enterocolitica 1B, O : 8

The high-pathogenicity island (Yen HPI) of Yersinia enterocolitica biogroup (BG) 1B strains is associated with mouse virulence. Three repeated sequenc es are clustered on the A+T-rich part of the Yen HPI downstream of the fyuA yersiniabactin receptor gene in Y. enterocolitica O:8 strains WA-314 and 8 081. In addition to IS1328 and IS1400, the RS3 repeated sequence consists o f a novel insertion sequence, IS1329, inserted into the remnants of IS1222. This partial IS retains both 44-bp inverted terminal repeats (ITRs) of IS1 222 but has suffered deletions of different sizes in strains WA-314 and 808 1. IS1329 is 1243-bp long, carries 25-bp imperfect ITRs and two consecutive orfs capable to encode 110-amino acid (aa) and 249-aa proteins, respective ly. IS1329 is present only in BG 1B Y. enterocolitica strains. Similarly to IS1400, IS1329 and IS1222 belong to the IS3 group of mobile elements and s eem to have preference for the 'local hopping' into the A+T-rich part of th e Yen HPI. These insertion sequences may be responsible for the imprecise d eletions of the Yen HPI in strain WA-314. (C) 2000 Federation of European M icrobiological Societies. Published by Elsevier Science B.V. All rights res erved.