TABLE 3.

Promoter activity determined with LacZ reporter fusionsa

LacZ fusionFold change (WT value/Δcrp mutant value)Normalized fold change of promoter activity in WT relative to that in Δcrp mutant
Plasmid copy no.Miller units
plap-lacZ19.16434.7922.69
pstp-lacZ7.75107.7213.90
Empty pRS5513.156.29
  • a The upstream promoter DNA region of pla or pst was cloned into the pRS551 plasmid to fuse with the promoterless lacZ gene. β-Galactosidase activity (Miller units) was detected as the promoter activity. The copy number of recombinant or empty pRS551 was determined by real-time quantitative PCR, as described in Table 1, with primers specific for the pRS551-borne lacA gene. The detected change in plasmid copy number was set to 1 to generate a normalization factor that was subsequently used to generate the normalized change in promoter activity in the WT relative to that in the Δcrp mutant.