Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.10.3.3 (ascorbate oxidase)
 778 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A unique A/T-rich sequence (5'-AAAAAGTAAAAA-GTAAAAAAGTAAAAAG-3), referred to as the AGTA repeat, is found in the silencer region of the pumpkin ascorbate oxidase gene. A cDNA for protein (AOBP) that binds to the AGTA repeat was isolated from pumpkin by the southwestern method. The AOBP protein has a new class of zinc/DNA-binding domain named Dof/MOA domain that is highly conserved in many plant proteins and is significantly related to those of steroid hormone receptors and GATA1. Gel retardation analysis indicated that AOBP bound to the AGTA repeat through the Dof/MOA domain. Metal chelators, 1,10-phenanthroline and EDTA, specifically inhibited the DNA binding of AOBP, indicating that metal coordination plays an important role in DNA binding of AOBP. Thus, the Dof/MOA domain acts as a zinc/DNA-binding domain in AOBP. Gel retardation analysis with mutated oligonucleotides suggested that the Dof/MOA domain recognized the AGTA core sequence. AOBP mRNA was expressed in mature tissues of pumpkin, but was expressed only in small amounts or was not expressed in growing tissues. Furthermore, the expression was auxin-independent. The expression pattern of AOBP and that of ascorbate oxidase did not show a positive correlation.
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PMID:Characterization and expression of a new class of zinc finger protein that binds to silencer region of ascorbate oxidase gene. 987 65

The Dof (DNA-binding with one finger) proteins are plant transcription factors that have a highly conserved DNA-binding domain, called the Dof domain. The Dof domain, which is composed of 52 amino acid residues, is similar to the Cys2/Cys2 zinc finger DNA-binding domain of GATA1 and steroid hormone receptors, but has a longer putative loop than that in the case of these zinc finger domains. The DNA-binding function of ascorbate oxidase gene binding protein (AOBP), a Dof protein, was investigated by gel retardation analysis. When Cys was replaced by His, the Dof domain could not function as a Cys3/His- or a Cys2/His2-type zinc finger. The characteristic longer loop was essential for DNA-binding activity. Furthermore, heavy metals such as Co(II), Ni(II), Cd(II), Cu(II), Hg(II), Fe(II), and Fe(III) inhibited the DNA-binding activity of the Dof domain. Manganese ion as well as zinc ion was coordinated by the Dof domain in vitro. On the other hand, the analysis using inductively coupled argon plasma mass spectrometry (ICP-MS) showed that the Dof domain contained zinc ion but not manganese ion. Thus, the Dof domain was proved to function as a Cys2/Cys2 zinc finger domain.
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PMID:The Dof domain, a zinc finger DNA-binding domain conserved only in higher plants, truly functions as a Cys2/Cys2 Zn finger domain. 1487 13