Figure 6

A truncated version of ICE Hptfs4 in hspWAfrica strains. (A) Most hspWAfrica strains (exemplified here by J99) have an ICEHptfs4 variant composed of ICEHptfs4a genes (compared here with P12) close to the left junction and ICEHptfs4b genes (compared here with G27) close to the right junction of the island. In these strains, the left part of the island is shortened by 350 bp at a CATTCTT motif upstream of xerT, and the right part by approximately 3850 bp at a CATTCTT motif within ICEHptfs4b virB4, generating irregular left and right junctions (ILJ and IRJ). In strain PeCan18, the ICEHptfs4a fragment has probably been integrated in a similar manner, using irregular integration at the same chromosomal position, but the majority of ICEHptfs4a seems to have been deleted subsequently by (regular) integration of an ICEHptfs3 at the same internal virB4 motif and another internal CATTCTT motif upstream of ICEHptfs4a virB6. Gene colouring is as in Figure 1, and asterisks denote frameshift or nonsense mutations (B) PCR analysis of the ICEHptfs4b right junction in H. pylori strains from Nigeria. PCR was performed from chromosomal DNA of the indicated strains with primers WS606 and WS539 (see Figure 6A).