TABLE 4.
In vivo mcp promoter activity
| Plasmida (lacZ fusion) | Cloned regionb (bp) | β-Galactosidase activityc (Miller units) |
|---|---|---|
| pRU2899 (mcpS [che2]) | −860/+9 | 4 |
| pRU2728 (mcpT) | −317/+3 | 29 |
| pRU2283 (mcpU) | −418/+38 | 235 |
| pRU2896 (mcpV) | −413/+2 | 0 |
| pRU2784 (mcpW) | −301/+2 | 127 |
| pRU2994 (mcpX) | −585/+5 | 417 |
| pRU2898 (mcpY) | −723/+63 | 29 |
| pRU2787 (mcpZ) | −407/+2 | 154 |
| pRU2250 (icpA [che]) | −1804/+170 | 156 |
a
Transcription from nine chemoreceptor promoters was assessed with plasmid-borne lacZ fusions (Table 1) for the wild type (RU11/001) during exponential growth. Cells diluted in RB medium were layered on Bromfield agar plates and grown to an OD600 of 0.15 to 0.25 (see Materials and Methods). The che operon (che) is composed of the icpA, orf2, cheY1, cheA, cheW, cheR, cheB, cheY2, cheD, and orf10 genes (66). The second che operon (che2) is localized on the symA plasmid and composed of cheR, cheW, mcpS, cheA, and cheB (14, 26).
b
Length of the cloned promoter region upstream/downstream of the start codon.
c
β-Galactosidase activities (46) from three to five independent experiments were averaged.