TABLE 1.

Strains and plasmids used in this study

Strain or plasmidRelevant characteristic(s)Reference or source
E. coli and Shigella strains
    E. coli DH5αRoutine cloning and lacZ expressionInvitrogen
    E. coli TOP10Cloning PCR productsInvitrogen
    E. coli S17-1RP4 mobilization functions39
    S. flexneri 2457TAerobactin productionD. Kopecko
C. diphtheriae strains
    C7(−)Wild type, tox3
    C7(β)hm723dtxR mutant, tox+17
    PW8tox+, siderophore mutant23
    1737Russian clinical strain, tox+25
    HC1Chemically derived mutant C7(β), irp6A/G240D9
    C7AciuA integration mutant of C7(−)This study
    C7EciuE deletion mutant of C7(−)This study
    C7p6Airp6A deletion mutant of C7(−)This study
    C7A-1Site-specific mutant of C7(−), irp6A/G240DThis study
    1737AciuA deletion mutant of 1737This study
    1737EciuE deletion mutant of 1737This study
    1737p6Airp6A deletion mutant of 1737This study
    1737sidA/ciuEsidA ciuE double mutant of 1737This study
Plasmids
    pCR-BluntII-TOPORoutine E. coli cloning plasmid, KnrInvitrogen
    pCm2.6sacBC. diphtheriae shuttle vector with sacB, CmrThis study
    pCmSB-ORI6Allelic exchange vector, CmrThis study
    pKN2.6C. diphtheriae shuttle vector, Knr33
    pCM502Promoter-probe vector, Cmr31
    pKE1737 ciuE gene on pKN2.6This study
    pciuEP-lacZciuE promoter lac fusion in pCM502This study
    pciuAP-lacZciuA promoter lac fusion in pCM502This study