FIG. 1.

Partial restriction map of the hemin uptake locus (hmu) of Y. pestis KIM6+ illustrating the locations and directions of transcription of ORFs designated hmuP′RSTUV and upstream ORFs designated orfXY. The sequence for the ′orfX gene does not extend to a predicted 5′ start site. The sequence of this region (7,623 bp) from the EcoRI site to beyond the end of hmuV has been deposited in GenBank under accession no. U60647. The location of the primary promoter region (p1) is shown upstream of hmuP′; a second promoter region (p2) is proposed upstream of hmuS (open arrowheads). Numbers next to the restriction enzymes refer to the locations (in kilobases) of key restriction sites. Clones generated from the hmu locus as well as deletions and insertions generated in the Y. pestis KIM6+ chromosome that were used in this study are illustrated below the genetic map. The in-frame ΔhmuS mutation generated within pHMU66 is identical to that generated within the chromosome (ΔhmuS-2062.1).