FIG. 4.
In vivo transcription assays. E. coli C41 cells were transformed with pET22b-PrrnD-lacZ or with the pET22b-PaidB-lacZ vector, and the β-galactosidase specific activity was monitored in the absence and in the presence of recombinant proteins L1, L2, L3, L20, and L27. The β-galactosidase activity was evaluated at log phase. Open bars, β-galactosidase activity in the absence of recombinant protein production; gray bars, β-galactosidase activity when recombinant L2 was overproduced; black bars, β-galactosidase activity in the presence of L1, L3, L20, or L27. Means and standard deviations were calculated from the results of three independent assays. The β-galactosidase activities for the PrrnD-lacZ fusion in the presence and in the absence of L2 expression were 52,700 and 3,160 Miller units, respectively; and the β-galactosidase activities for the PaidB-lacZ fusion in the presence and in the absence of L2 expression were 357 and 355 Miller units, respectively. The β-galactosidase activities for the two promoter-lacZ fusions in the presence of L1, L3, L20, or L27 and in the absence of recombinant protein expression were about 360 Miller units. The background activity for the lacZ fusion vector without any promoter insert was 62 Miller units.