TABLE 5.
SetD and SetC stimulate SXT transfer gene expression
| Site of fusiona | β-Galactosidase activityb
|
|
|---|---|---|
| − | + | |
| Δ(traL-traA)::lacZ | 1.3 | 53 |
| Δs003::lacZ | 6.5 | 320 |
| ΔtraG::lacZ | 10 | 340 |
| ΔsetDC::lacZ | 8.4 | 340 |
| ΔfloR::lacZ | 46 | 38 |
a
All strains are derivatives of BW25113 (7) containing SXT.
b
Cells containing a plasmid with setDC under control of an arabinose-inducible promoter (pSetCD) were grown in LB broth containing 100 μg of ampicillin/ml for 2.5 h. Arabinose was then added to half of the culture to a final concentration of 1 mM, and the cells were grown for an additional 1.5 h. β-Galactosidase activity, reported in Miller units, was measured as described by Miller (21). The values presented are the means of at least three independent experiments. +, setDC expression; −, no setDC expression.