TABLE 3.
Transcription of four fla promoters fused to lacZ in wild-type and fla mutant tester strains of S. meliloti
| Genotype of tester strain | Relative promoter activity assessed with lacZ fusions ina:
|
Fla proteinb | |||
|---|---|---|---|---|---|
| pRU2274 (flaA-lacZ) | pRU2275 (flaB-lacZ) | pRU2276 (flaC-lacZ) | pRU2277 (flaD-lacZ) | ||
| Wild type | 1.00 (14,000) | 1.00 (2,400) | 1.00 (2,200) | 1.00 (160) | ++ |
| ΔflaA | 0.26 | 1.04 | 1.06 | 1.14 | + |
| ΔflaB | 0.77 | 0.98 | 1.06 | 0.98 | ++ |
| ΔflaC | 1.11 | 1.00 | 1.02 | 0.90 | ++ |
| ΔflaD | 1.05 | 0.97 | 1.01 | 0.98 | ++ |
| ΔflaAB | 0.22 | 1.00 | 0.99 | 1.07 | (+) |
| ΔflaAC | 0.23 | 0.97 | 1.08 | 0.96 | (+) |
| ΔflaBC | 0.78 | 1.04 | 1.04 | 0.95 | ++ |
| ΔflaBD | 0.71 | 0.98 | 1.05 | 1.03 | ++ |
| ΔflaCD | 0.67 | 0.99 | 0.95 | 0.81 | ++ |
| ΔflaABC | 0.25 | 0.99 | 1.03 | 1.03 | NDc |
| ΔflaABD | 0.24 | 1.05 | 0.96 | 0.95 | (+) |
| ΔflaACD | 0.22 | 1.04 | 1.05 | 0.85 | (+) |
| ΔflaBCD | 0.33 | 1.03 | 0.98 | 0.83 | (+) |
| ΔflaABCD | 1.12 | 1.08 | 1.07 | 0.71 | − |
Relative activities are expressed as ratios of β-galactosidase activity in the indicated mutant backgrounds to that in the wild-type background. Transcription from four fla promoters was assessed with plasmid-borne lacZ fusions (see Materials and Methods). Mean values of Miller assays (24) were averaged, with standard deviations ranging between 0.01 and 0.15. Values in parentheses are Miller units of β-galactosidase activity (24) averaged from the results of three independent assays. The reduced flaA promoter activities are highlighted by boldface numbers.
Approximate amounts of flagellin deduced from immunoblot (Fig. 5) band intensities. ++, normal; +, reduced; (+), severely reduced; −, zero.
ND, not determined.