FIGURE 7.

Redox modulation of AtbZIP68 and AtGBF1 binding affinities to the G-box. A, the effect of DTT and H₂O₂ on DNA binding activity of GBF1 was tested by EMSA. EMSA was performed using biotin-labeled complementary synthetic oligonucleotides representing the G-box element without protein or with GBF1-WT, 10 mm DTT, and 10 mm H₂O₂. B, binding of GBF1-WT protein and its mutant variants to the G-box element. Binding reactions in the absence of GBF1 protein or with GBF1-WT, GBF1 containing a Cys to Leu mutation at position 275, or GBF1 containing a Cys to Leu mutation at position 247. C, the effect of DTT and H₂O₂ on DNA binding activity of bZIP68 was analyzed by EMSA. Binding reactions in the absence or presence of bZIP68 protein, 10 mm DTT, and 10 mm H₂O₂. D, binding of bZIP68-WT protein and its mutant variants to the G-box element. EMSA was performed using the biotin-labeled G-box element without protein or with bZIP68-WT, bZIP86 containing a Cys to Leu mutation at position 320, or bZIP68 containing a Cys to Leu mutation at position 182. Biotin-labeled probes were detected with a chemiluminescent nucleic acid detection module, and positions of free DNA and protein-DNA complexes are indicated by arrows.