Modulation of gene expression by DNA-protein and protein-protein interactions in the promoter region of the zein multigene family.
A common cis-acting element in the promoter region of many genes expressed during endosperm development of cereal seeds, the prolamine-box or P-box, is only 20bp upstream of the alpha-class 22-kDa zein gene-specific cis element, the O2-box, which is recognized by the b-ZIP transcription factor, Opaque-2 (O2). The proximity of these two boxes has prompted a study of how two DNA-binding proteins of a different hierarchy might be involved in the activation and modulation of the 22-kDa zein-encoding genes. This was accomplished by utilizing a highly purified P-box-binding-factor-1 (PBF-1) and a bacterially expressed truncated form of the O2 protein. After adding the recombinant O2 to the purified fraction of PBF-1, binding studies were performed with a series of DNA probes combining the P- and O2-boxes from zein promoters. These studies have revealed an interesting inhibitory effect of PBF-1 over O2 function dependent on their ratio, consistent with its in-vivo properties and the developmental expression profiles of zein genes. We also could show that the P-box is specifically recognized by topoisomerase II and single-strand DNA-binding proteins, indicating a possible additional linkage between P-box and the scaffold-attachment-region (SAR).
Wang
Z
Z
Waksman Institute, Rutgers, The State University of New Jersey, Piscataway, NJ 08855-0759, USA.
Messing
J
J
D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D005810:Multigene Family; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D003313:Zea mays / Q000235:genetics / Q000378:metabolism; D015028:Zein / Q000235:genetics* / Q000378:metabolism
D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; C115836:PBF protein, plant; D010940:Plant Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors; D015028:Zein