TABLE 1.
Strains and plasmids used in this study
| Strain or plasmid | Relevant characteristics | Reference or source |
|---|---|---|
| E. coli | ||
| DH5α | F−supE44 ΔlacU169 (φ80 lacZ ΔM15) hsdR17 recA1 endA1 gyrA96 thi-1 relA1 | Gibco BRL |
| CJ236 | dut ung thi relA; pCJ105 (Cmr) | Bio-Rad |
| SG22098 | MC4100 clpP::cat (Cmr) | S. Gottesman |
| Plasmids | ||
| pBluescript SKII(−) | Wild type; Apr | United States Biochemicals |
| pDtxR-7 | dtxR under the transcriptional control of the T7 promoter in pT7-7 | 27 |
| pSKIIdtxR | 1.1 kb BglII-EcoRI fragment from pDtxR-7 in pBluescript SKII(−) | This study |
| pWKS30 | Wild type; Apr | 38 |
| pCMZ100 | tox-lacZ translational fusion in E. coli-C. diphtheriae shuttle vector pCM2.6; Cmr | 26 |
| pTXZ184 | Derivative of pACYC184 carrying tox-lacZ translational fusion; Tcr | 25 |