TABLE 1.
E. coli K-12 strains used in this study
| Strain(s) | Description | Reference or source |
|---|---|---|
| FC29 | Δ(lac-proAB)XIIIthi ara[F′ Δ(lacI-lacZ)] | 3 |
| FC36 | Δ(lac-proAB)XIIIthi ara Rifr | 3 |
| FC40 | Δ(lac-proAB)XIIIthi ara Rifr[F′ proAB+lacI33ΩlacZ] | 3 |
| AB1157 Δ(dinB-yafN)::kan | 12; via F. Taddei | |
| MG1655 | Wild type | 1 |
| P90C | Δ(lac-proAB)XIII | 4 |
| SMR3804, SMR3805, SMR3807, SMR3855- SMR3859, SMR3861, SMR3863 | 10 independent Lac+ revertants of FC40; dinB+ | 20a |
| SMR4511 | MG1655 ΔlacX74 proAB-81::Tn10 | This workb |
| SMR4562 | Genotype same as that of FC40, independent construction | 18 |
| SMR5816 | P90C[F′ proAB-81::Tn10 lacI33ΩlacZ] | This workc |
| SMR5830 | SMR4562 dinB10[F′ dinB10 proAB+lacI33ΩlacZ]d | 19 |
| SMR5865-SMR5874 | 10 independent Lac+ revertants of SMR5830 | 19a |
| SMR5889 | SMR4562 ΔdinB51[F′ ΔdinB51 proAB+lacI33ΩlacZ]d | This work |
| SMR6111 | SMR4562 Δ(dinB-yafN)::kan[F′ Δ(dinB-yafN)::kan proAB+lacI33ΩlacZ]d | This work |
| SMR6356-SMR6365 | 10 independent Lac+ revertants of SMR6111 | This worka |
| SMR7481-SMR7490 | 10 independent Lac+ revertants of SMR5889 | This worka |
| SMR7491 | SMR4562 Δ(yafN-yafP)602[F′ Δ(yafN-yafP)602 proAB+lacI33ΩlacZ]d | This work |
| SMR7492-SMR7501 | 10 independent Lac+ revertants of SMR7491 | This workb |
a
Spontaneous Lac+ revertants were isolated, one each from 10 independent cultures.
b
Construction made by P1 transductions with the proAB-81::Tn10 and ΔlacX74 alleles derived from strains NK5525 (kindly provided by N. Kleckner via the E. coli Genetic Stock Center, Yale University) and CH1504 (16), respectively.
c
Construction made by P1 transduction of proAB-81::Tn10 derived from strain NK5525 (kindly provided by N. Kleckner) into the F′ derived from FC40 and mating into P90C.
d
The dinB and yafN-yafP genes are present on both the chromosome and F′, and so homozygous mutant strains were constructed.