TABLE 1.

Bacterial strains and plasmids used in this study

Strain or plasmidRelevant phenotype or genotypeReference or origin
E. coli strains
    W3104Wild-type strain25
    DH5αsupE44 ΔlacU169 (φ80lacZΔM15) hsdR17 recA1 gyrA96 thi-1 recA1Takara Shuzo Co.
    TG1supE hsdΔ5 thi Δ(lac-proAB) F′ [traD36 proAB+ lacIq lacZΔM15]Takara Shuzo Co.
    KAM3Derivative of TG1 that lacks a restriction system and acrAB12
    KO6494Derivative of KAM3 that lacks mdtB (formerly yegN)This study
    TG1ΔtolCDerivative of TG1 that lacks tolCThis study
Plasmids
    pUC119Vector; Apr; multiple cloning site in lacZTakara Shuzo Co.
    pQE30His expression vector; Apr; multiple cloning site downstream of T5 promoterQiagen
    pHSG398Derivative of pUC18 containing Cmr in place of Apr.Takara Shuzo Co.
    pUCyeg-mdt-bae14.2-kb SphI-EcoRI fragment containing yegKL (putative regulatory system), mdtABC (former name, yegMNO; putative MFP, putative RND transporter, putative RND transporter), mdtD (putative MF transporter), and baeSR (putative two-component system) genes cloned into pUC119, Apr16
    pUCmdtABCD9.5-kb PstI-SmaI fragment containing mdtABCD genes into pUC119, AprThis study
    pUCmdtABCBglII-SmaI fragment was removed from pUCmdtABCDThis study
    pUCyegLKyegLK genes with the promoter region were amplified from pUCyeg-mdt-bae by PCR and cloned into pUC119This study
    pUCmdtAmdtA gene with the native promoter was cloned into pUC119 as aboveThis study
    pUCmdtABmdtAB genes with the native promoter were cloned into pUC119 as aboveThis study
    pUCbaeSRbaeSR genes with the native promoter were cloned into pUC119 as aboveThis study
    pHSGbaeSRSphI-EcoRI fragment of pUCbaeSR was subcloned into the multicloning site of pHSG398This study
    pQEbaeSbaeS gene was amplified by PCR from pUCbaeSR and cloned into pQE30 under the control of T5 promoterThis study
    pQEbaeRbaeR gene was cloned into pQE30 as aboveThis study
    pTrc99AExpression vector; multiple cloning site downstream of trc promoter, AprAmersham Pharmacia Biotech
    pTrcmdtC3.1-kb EcoRI-PstI fragment containing mdtC gene cloned into pTrc99A, AprThis study
    pTrcmdtBC6.2-kb EcoRI-PstI fragment containing mdtB and mdtC genes cloned into pTrc99A, AprThis study
    pACYC177Vector; Apr, KmrMBI Fermentas
    pACYCmdtA2.9-kb PstI-BamHI fragment containing mdtA gene cloned into pACYC177, KmrThis study