title: Maize ABI4 binds coupling element1 in abscisic acid and sugar response genes.
abstract: Significant progress has been made in elucidating the mechanism of abscisic acid (ABA)-regulated gene expression, including the characterization of an ABA-responsive element (ABRE), which is regulated by basic domain/Leu zipper transcription factors. In addition to the ABRE, a coupling element (CE1) has been demonstrated to be involved in ABA-induced expression. However, a trans factor that interacts with CE1 has yet to be characterized. We report the isolation of a seed-specific maize ABI4 homolog and demonstrate, using a PCR-based in vitro selection procedure, that the maize ABI4 protein binds to the CE-1 like sequence CACCG. Using electrophoretic mobility shift assays, we demonstrate that recombinant ZmABI4 protein binds to the CE1 element in a number of ABA-related genes. ZmABI4 also binds to the promoter of the sugar-responsive ADH1 gene, demonstrating the ability of this protein to regulate both ABA- and sugar-regulated pathways. ZmABI4 complements Arabidopsis ABI4 function, because abi4 mutant plants transformed with the ZmABI4 gene have an ABA- and sugar-sensitive phenotype. Identification of the maize ABI4 ortholog and the demonstration of its binding to a known ABA response element provide a link between ABA-mediated kernel development and the regulation of ABA response genes.
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology*; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002241:Carbohydrates / Q000494:pharmacology*; D025222:Chloroplast Proton-Translocating ATPases / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D003313:Zea mays / Q000235:genetics* / Q000378:metabolism
chemical_list: C470421:ABI4 protein, Arabidopsis; C499534:APETALA2 protein, Arabidopsis; D029681:Arabidopsis Proteins; D002241:Carbohydrates; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D009687:Nuclear Proteins; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D000040:Abscisic Acid; D025222:Chloroplast Proton-Translocating ATPases