Table 3.
Influence of an opuE mutation on the transcriptional activity of the proH and the opuE promotersa
| Strain | treA fusion | opuEb | TreA enzyme activity (U/mg protein) |
||
|---|---|---|---|---|---|
| Without NaCl | With 0.5 M NaCl | With 1.0 M NaCl | |||
| JSB36 | proH-treA | + | 23 ± 1 | 46 ± 3 | 122 ± 5 |
| TMB119 | proH-treA | − | 24 ± 1 | 41 ± 8 | 109 ± 16 |
| TRB2 | opuE-treA | + | 25 ± 4 | 84 ± 5 | 190 ± 65 |
| TRB12 | opuE-treA | − | 17 ± 1 | 77 ± 12 | 213 ± 17 |
a
Cells carrying chromosomal copies of the indicated proH-treA and opuE-treA operon reporter fusions were cultivated in either SMM, SMM with 0.5 M NaCl, or SMM with 1.0 M NaCl to mid-exponential growth phase (OD578 of 1.5) and were then harvested for TreA reporter enzyme activity assays. Each TreA activity measurement was carried out with three independently grown cultures and in each case included two technical replicates of the TreA enzyme assay.
b
Strains carrying an opuE mutation (indicated by a minus) all harbored the Δ(opuE::tet)1 allele.