Figure 4.

The PLATZ1 protein binds to the enhancer element of the pea plastocyanin gene (petE). (A) The sequence similarity between the 30-bp A/T-rich sequence of the pra2 gene and the 31-bp A/T-rich enhancer of the pea petE gene. (B) EMSA using the 31-bp A/T-rich enhancer of the pea petE gene. Binding reactions were carried out with the recombinant PLATZ1 protein and the ³²P-labeled 31-bp A/T-rich enhancer fragment (100 fmol) in the absence or presence of the unlabeled 31-bp A/T-rich enhancer fragment as competitor. Lane 1, no protein; lane 2, 100 ng PLATZ1 protein; lanes 3–5, 200 ng PLATZ1 protein. As indicated, 100 and 200-fold competitors were added (lanes 4 and 5). An arrow indicates a protein-bound complex. (C) Competition experiments using oligonucleotides poly(dA–dT)–poly(dA–dT) and the labeled enhancer fragment of the pea petE gene. Lane 1, no protein; lane 2, 100 ng PLATZ1 protein; lanes 3–5, 200 ng PLATZ1 protein. As indicated, 50 ng and 100 ng of competitors were added (lanes 4 and 5). An arrow indicates a protein-bound complex.