Figure 3.
Binding of rArlR to the spx promoter region (EMSA). The promoter regions of spx and arlR (as a control) were amplified and labelled with digoxin (DIG). Lanes 1–5 were loaded with 0.4 ng DIG-arlR promoter region and increasing amounts of recombinant ArlR (0, 0.5, 1, 1.5, 2 μg respectively). Lanes 6–10 were loaded with 0.4 ng DIG-spx promoter region and increasing amounts of recombinant ArlR (0, 0.5, 1, 1.5, 2 μg respectively). The DIG-labelled DNA fragments were transferred to positively charged nylon membranes and visualized by an enzyme immunoassay using anti-Digoxigenin-AP, Fab-fragments and the chemiluminescent substrate CSPD. Chemiluminescent signals were recorded on X-ray film.