TABLE 4.
Effects of altered DnaK or GroE chaperone level on transcription from the rpoH promotera
| Strain | Chaperone level | Relative β-galactosidase activity |
|---|---|---|
| rpoH+ strains | ||
| KN613(pBBR122)(pUCD-PrpoH′-lacZ) (control) | Normal | 1 |
| KN613(pBBR122-dnaKJr)(pUCD-PrpoH′-lacZ) | Excess DnaKJ | 0.38 ± 0.05 |
| KN613(pBBR122-groESLr)(pUCD-PrpoH′-lacZ) | Excess GroESL | 0.96 ± 0.27 |
| KN615 Ptrc-groESL(pBBR122)(pUCD-PrpoH′-lacZ) | Reduced GroESL | 1.21 ± 0.05 |
| Plac′-rpoH strains | ||
| KN209(pBBR122)(pUCD-PrpoH-lacZ) (control) | Normal | 1 |
| KN214 Ptrc-dnaKJ(pBBR122)(pUCD-PrpoH′-lacZ) | Reduced DnaKJ | 10.60 ± 4.55 |
a
The pUCD-PrpoH′-lacZ reporter plasmid was inserted in the strains used in Fig. 6; the control and the chaperone-underexpressing strains were also made to carry pBBR122 plasmid. Cells were grown to log phase in synthetic medium at 25°C, and portions of these cell cultures were assayed for β-galactosidase activity and normalized to the value of the respective control. Averages from at least three experiments with standard errors are shown. The activities for the two control strains were comparable.