Local hopping of IS 3 elements into the A+T-rich part of the high-pathogenicity island in Yersinia enterocolitica 1B, O:8

Abstract

The high-pathogenicity island (Yen HPI) of Yersinia enterocolitica biogroup (BG) 1B strains is associated with mouse virulence. Three repeated sequences 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 8081. In addition to IS 1328 and IS 1400, the RS3 repeated sequence consists of a novel insertion sequence, IS 1329, inserted into the remnants of IS 1222. This partial IS retains both 44-bp inverted terminal repeats (ITRs) of IS 1222 but has suffered deletions of different sizes in strains WA-314 and 8081. IS 1329 is 1243-bp long, carries 25-bp imperfect ITRs and two consecutive orfs capable to encode 110-amino acid (aa) and 249-aa proteins, respectively. IS 1329 is present only in BG 1B Y. enterocolitica strains. Similarly to IS 1400, IS 1329 and IS 1222 belong to the IS 3 group of mobile elements and seem to have preference for the ‘local hopping’ into the A+T-rich part of the Yen HPI. These insertion sequences may be responsible for the imprecise deletions of the Yen HPI in strain WA-314.