TABLE 1.
E. coli strains, plasmids, and phages
| Strain, plasmid(s), or phage | Genotype or description | Reference(s) or source |
|---|---|---|
| Strains | ||
| CB454 | Selector strain; ΔlacZ galK rpsL recA56 | 20 |
| DH5α | Cloning strain; hsdR17(rK− mK+) recA1 endA1 gyrA96 thi relA1 supE44 φ80dlacZΔM15 Δ(lacZYA argF)U169 | Gibco-BRL |
| JM101 | Mutagenesis strain; Δ(lac-proAB) thi supE F′ [traD36 proAB lacIqZΔM15] | 29 |
| NK5031(λtet50) | Source of tetA-lacZ transcriptional fusion; ΔlacM5265 supF nalR thi; λtet50 is integrated in single copy into the NK5031 genome | 23 |
| RZ1032 | Mutagenesis strain; HfrKL16 PO/45 lysA(61-62) dut-1 ung-1 thi-1 relA1 supE44 Zbd-279::Tn10 | 13 |
| SCS1 | Cloning strain; hsdR17(rK− mK+) recA1 endA1 gyrA96 thi-1 relA1 supE44 | Stratagene |
| WH207 | Tester strain; ΔlacX74 galK2 rpsL recA | 28 |
| Plasmids | ||
| pWH520, pWH520Δ164–166 | Derivatives of pWH1201; tetR and tetR Δ164–166 expression plasmids | 3, 4 |
| pWH1012 | Apr; pBR322 derivative; tetA-lacZ transcriptional fusion | 22 |
| pWH1201 | Cloning vector; Kmr; pACYC177 derivative | 1 |
| pWH1919 | Same as pWH520; tetR with additional restriction sites for BstXI and MluI | 8 |
| pWH1919-X | X:RQ49, DY53; YC110; LS117; LF146; EG150; HR151; tetR mutants chosen for suppression | 8 |
| Phages | ||
| λtet50 | Wild-type cI; tetA-lacZ transcriptional fusion | 23 |
| mWH819 | Mutagenesis vector | 27 |