Figure 5.

AHBP-1b interacts specifically with the A. thaliana PR-1 promoter sequence containing an as-1-like element. All binding reactions contain 4 × 10⁴ cpm ³²P-labeled probe, incubated with 1 μg of either a control protein preparation (lane 1) or AHBP-1b (lanes 2–10), in the absence (lanes 1 and 2) or presence of specific (lanes 3–6) or nonspecific (lanes 7–10) competitor probes. In lanes 3–6, 1×, 10×, 40×, and 100× molar excess of the unlabeled as-1-like probe were added, respectively. In lanes 7–10, 1×, 10×, 40×, and 100× molar excess of the unlabeled probe containing point mutations in the as-1-like element were added, respectively. S, specific band shifting; ∗, nonspecific banding; FP, free probe.