TABLE 2.
Plasmids carrying dnaC complement the temperature-sensitive phenotype of dnaC mutants
| Strain | Plasmid | Relative frequency of colony formationa |
|---|---|---|
| SS1020 (dnaC2) | None | <10−8 |
| SS1020 (dnaC2) | pBR322 | 1.2 × 10−7 |
| SS1020 (dnaC2) | pdnaC113 | 7 × 10−2 |
| SS1020 (dnaC2) | pINCSSD | 2 × 10−2 |
| PC2 (dnaC2) | None | <10−8 |
| PC2 (dnaC2) | pACYC184dnaC | ∼1 |
| SS1020 (dnaC2) | None | <10−8 |
| SS1020 (dnaC2) | pAM34 | <10−8 |
| SS1020 (dnaC2) | pAM34dnaCL1-2 | ∼1b |
| SS1020 (dnaC2) | pAM34dnaCL1-4 | ∼1b |
Cultures of E. coli PC2 (dnaC2) or SS1020 (dnaC2) carrying the indicated plasmids were grown at 30°C in LB media supplemented with 10 μg/ml tetracycline, 100 μg/ml ampicillin or 50 μg/ml kanamycin to select for the respective plasmid. After serial dilution, the samples were plated on antibiotic-supplemented LB media followed by incubation at 30°C or 42°C for about 14 h. Transformants carrying pAM34 and its derivatives were plated on medium with or without 0.5 mM IPTG. The relative frequency of colony formation is the ratio of the number of colonies detected at 42°C to that at 30°C.
Colony formation, which was observed at 42°C for the transformants carrying pAM34dnaCL1-2 and pAM34dnaCL1-4, required IPTG in the culture medium.