FIG. 1.

Physical map of the HPI element of pathogenic yersiniae. Important genes are indicated by large black arrows and include the following: asnT and int boundary genes; ybtS, ybtQ, ybtA, irp2, irp1, ybtU, ybtT, and ybtE, constituting the siderophore yersiniabactin biosynthetic gene cluster; fyuA, encoding the receptor for yersiniabactin and pesticin; and IS100 insertion element (7, 13, 34, 38). PCR primers used to target single HPI genes (panel A, regions III to VIII, X, and XI) or to link consecutive genes (panel A, regions I, II, and IX, and panel B) are indicated by small arrows, and nucleotide sequences of the primers are given in Table 2.