TABLE 5.
Effects of nac on expression of plasmid-borne Φ(nasR-lacZ) and Φ(hutU-lacZ) operon fusions
| Genotypea | Fusionb | β-Galactosidase sp actc with:
|
|||
|---|---|---|---|---|---|
| No IPTG
|
IPTG added
|
||||
| NH4+, Gln | Gln | NH4+, Gln | Gln | ||
| nac+ | nasR | <1 | 230 | —d | — |
| nasR −29/−28AT→GC | 4 | 290 | — | — | |
| hutU | 260 | 9,510 | — | — | |
| nac::Tn5 | nasR | <1 | 670 | — | — |
| nasR −29/−28AT→GC | <1 | 460 | — | — | |
| hutU | 240 | 1,340 | — | — | |
| tac-nac+ | nasR | <1 | 230 | 8 | 140 |
| nasR −29/−28AT→GC | <1 | 300 | 9 | 150 | |
| hutU | 340 | 3,270 | 6,830 | 6,230 | |
| tac-nac+ ntrC | nasR | <1 | <1 | 6 | 3 |
| nasR −29/−28AT→GC | <1 | <1 | 8 | 9 | |
| hutU | 460 | 1,090 | 3,610 | 3,250 | |
a
K. aerogenes W70 strains (Table 1).
b
Φ(nasR-lacZ) {−469/+71} gene fusion on plasmids pVJS3004 (wild type) and pVJS3029 (−29/−28AT→G), and Φ(hutU-lacZ) operon fusion on plasmid pV16 (Table 1).
c
Determined as described in Materials and Methods and expressed in arbitary (Miller) units. Cultures were aerated in media containing the indicated nitrogen sources as described in Materials and Methods.
d
—, not determined.