TABLE 2.
TnrA effect on expression of gltA and gltC
| Strain | Genotype | gltA-gltC region of fusion | β-Galactosidase activity, Miller units (gltA-lacZ fusion)
|
β-Glucuronidase activity, Miller units (gltC-gusA fusion)
|
|||
|---|---|---|---|---|---|---|---|
| Ammonium | Ammonium + glutamate | Glutamate | Ammonium | Glutamate | |||
| LG200 | Wild type | Wild type | 75.8 | 26.1 | ≤2.1 | 0.7 | 1.1 |
| LG200-S | gltC | Wild type | NGb | 1.0 | 0.5 | NG | 8.0 |
| LG203 | Wild type | gltAp3 | 118.1 | 54.5 | 6.3 | 1.1 | 1.8 |
| LG203-S | gltC | gltAp3 | NG | 8.7 | 1.1 | NG | 11.9 |
| LG203-T | tnrA | gltAp3 | 120.1 | 52.7 | 56.7 | 1.2 | 2.8 |
| LG203-ST | gltC tnrA | gltAp3 | NG | 8.9 | 12.3 | NG | 23.4 |
| LG219 | Wild type | Wild typea | 74.2 | 30.8 | ≤2.0 | 14.6 | 16.9 |
| LG219-S | gltC | Wild type | NG | 0.9 | 0.3 | NG | 85.8 |
| LG219-T | tnrA | Wild type | 73.2 | 27.6 | 34.6 | 13.5 | 25.3 |
| LG219-ST | gltC tnrA | Wild type | NG | 0.9 | 1.0 | NG | 87.2 |
| LG219/24 | Wild type | gltAp24 | 74.4 | NDc | 32.6 | ND | 15.4 |
| LG219/24-T | tnrA | gltAp24 | 78.0 | ND | 31.2 | ND | ND |
a
Strains of the LG219 series contain a gltAp19 mutation (2) (Fig. 1) within their fusions. This mutation does not affect expression or regulation from the gltA promoter but strongly increases expression from the gltC promoter (compare LG200 and LC219) and was used to increase activity of the gltC-gusA fusion.
b
NG, no growth. gltC mutants cannot grow in ammonium medium because they require glutamate for growth.
c
ND, not determined.