TABLE 2 .
Bacterial strains and plasmids used in this study
| Strain or plasmid used | Description | Reference or source |
|---|---|---|
| Strains | ||
| C. difficile R20291 | NAP1/027 ribotype | 31 |
| C. difficile R20291::tcdR | R20291with intron insertion in tcdR gene | This study |
| C. difficile 630Δerm | Erm′ derivative of strain 630 | 63 |
| C. difficile 630Δerm::tcdR | 630Δerm with intron insertion in tcdR gene | This study |
| E. coli DH5α | endA1 recA1 deoR hsdR17 (rK− mK+) | NEB laboratories |
| E. coli S17-1 | Strain with integrated RP4 conjugation transfer function for conjugation between E. coli and C. difficile | 59 |
| E. coli GM241(DE3) | gusA mutant lysogenized with DE3 phage and host for gusA reporter plasmids | 54 |
| Plasmids | ||
| pMTL007-CE5 | ClosTron plasmid | 18 |
| pMTL007-CE5::tcdR-141 | pMTL007-CE5 carrying tcdR-specific intron | This study |
| pRPF185 | C. difficile shuttle vector | 64 |
| pRGL294 | pRPF185 with tcdR expressed from its own promoter | This study |
| pACYC184 | E. coli cloning vector; compatible with pET16B | Neb |
| pACYC515 | pACYC184 vector carrying gusA gene under the control of the tcdR promoter | 54 |
| pET16b | E. coli expression vector | Novagen |
| pRGL312 | pET16B with tcdR | This study |
| pRGL320 | pACYC184 vector carrying gusA gene under the control of the bclA2 promoter | This study |
| pRGL321 | pACYC184 vector carrying gusA gene under the control of the bclA3 promoter | This study |
| C. difficile R20291::tcdR + pRGL294 | R20291::tcdR complemented with tcdR | This study |
| C. difficile R20291::tcdR + pRPF185 | R20291::tcdR with vector control | This study |