Figure 2.
Determination of NtrC versus Nac control. (A) Spot images for genes of the b1440–44 operon and the ddp (b1483–88) operon and adjacent genes in experiments a–k. (B) Profiles (log ratios) for these genes visualized as red and green intensities by using the program treeview (17) (http://rana.stanford.edu/software). The patterns expected for Nac or NtrC activation are red in experiments a–f or c–h, respectively. For either Nac or NtrC control green spots are expected in experiments j and k. If there is no control other than NtrC/Nac, yellow or black spots (A) or black squares (B) are expected in experiment i. Note that genes flanking each operon have expression patterns different from those of the operon and that the first PCR product for b1486 (experiments c, e, i, j, and k) was apparently bad. Red and green intensities representing induction and repression ratios, respectively, are indicated to the left of B.