Binding of WRKY28 to ICS1 promoter fragments. (A) EMSAs were performed with promoter fragments of 30 bp, each containing a TGAC core sequence (positions -278, -445/-460, -648, -725) or a WK-like box (-844) in the center. The location of these sequences in the ICS1 promoter relative to the transcription start site is given above the lanes. (B) EMSAs were performed with a 30-bp fragment of the ICS1 promoter containing TGAC core sequences at position -445 and -460. The EMSAs in panel B were done without addition of unlabeled competitor DNA, or in the presence of a 50-fold or 250-fold excess of unlabeled competitor DNA as indicated above the lanes. The promoter fragments were incubated with recombinant GST/WRKY28 fusion protein (plus-signs) or without this protein (minus-signs). The position of protein-DNA complexes is indicated by an arrow.