A maize protein associated with the G-box binding complex has homology to brain regulatory proteins.
The G-box element is a moderately conserved component of the promoter of many inducible genes, including the alcohol dehydrogenase genes of Arabidopsis and maize. We used monoclonal antibodies generated against partially purified G-box binding factor (GBF) activity to characterize maize proteins that are part of the DNA binding complex. Antibodies interacted with partially purified maize GBF complexes to produce a slower migrating complex in the gel retardation assay. Immunoprecipitation experiments suggested that the protein recognized by the antibody is not a DNA binding protein in and of itself, but rather is associated with the DNA binding complex. These monoclonal antibodies were used to isolate cDNA clones encoding a protein that we have designated GF14. Maize GF14 contains a region resembling a leucine zipper and acidic carboxy and amino termini, of which the latter can form an amphipathic alpha-helix similar to known transcriptional activators such as VP16 and GAL4. Protein gel blot analysis of cell culture extract showed that a single, major protein of approximately 30 kD is recognized by anti-GF14; the protein is also present predominantly in the kernel and root. The deduced amino acid sequence of maize GF14 is more than 80% identical to Arabidopsis GF14 and Oenothera PHP-O, and is more than 60% identical to a class of mammalian brain proteins described as both protein kinase C inhibitors and activators of tyrosine and tryptophan hydroxylases. GF14 is found in a variety of monocotyledons and dicotyledons, gymnosperms, and yeast. This suggests a deep evolutionary conservation of a potential regulatory protein associated with a core sequence found in the promoter region of many genes.
de Vetten
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Horticultural Sciences Department, University of Florida, Gainesville 32611.
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D048948:14-3-3 Proteins; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001923:Brain Chemistry; D047388:Casein Kinases; D002417:Cattle; D003001:Cloning, Molecular; D017124:Conserved Sequence; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D005786:Gene Expression Regulation; D017343:Genes, Plant; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics*; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D014446:Tyrosine 3-Monooxygenase; D003313:Zea mays / Q000737:chemistry / Q000235:genetics*
D048948:14-3-3 Proteins; D004268:DNA-Binding Proteins; D009419:Nerve Tissue Proteins; D014446:Tyrosine 3-Monooxygenase; D011494:Protein Kinases; D047388:Casein Kinases