Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.6.1.44 (AGT)
 770 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The EPF family is a group of transcription factors containing canonical Cys2/His2-type zinc finger motifs that were first discovered in plants. These zinc finger proteins are characterized by two zinc fingers that are separated by spacers of various lengths, which are much longer than typical spacers (HC-link) in cluster-type zinc finger proteins. We describe here direct evidence that the two zinc fingers make contact with two tandemly repeated AGT core sequences that are separated by about 13 base pairs, by contrast to the cluster-type zinc finger proteins that bind to contiguous triplet sequences. DNA binding affinities were sensitive to the spaces between the core sequences, and the sensitivity to the spacing was greatly affected by the DNA sequence between the core sequences, with GC-rich sequences endowing much higher specificity than AT-rich sequences. Among the members of the EPF family, EPF1 was less sensitive to the spacing than EPF2-5. These results suggest that EPFs recognize their cognate target DNAs not only by the sequence of the core sites but also by the spacing between the core sites and, moreover, that different members in the EPF family distinguish their specific target genes by reference to these two parameters. This represents a unique type of target-sequence recognition among Cys2/His2-type zinc finger transcription factors. In addition, site-directed mutagenesis studies demonstrated that the two zinc fingers contribute synergistically to the binding to DNA, indicating that both fingers are necessary for the high affinity DNA binding.
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PMID:Target-sequence recognition by separate-type Cys2/His2 zinc finger proteins in plants. 879 40

ZPT2-2 is a DNA-binding protein of petunia that contains two canonical TFIIIA-type zinc finger motifs separated by a long linker. We previously reported that ZPT2-2 bound to two separate AGT core sites, with each zinc finger making contact with each core site. Here we present our further characterization of ZPT2-2 by using selected and amplified binding sequence imprinting and surface plasmon resonance analyses; together, these assays revealed some unusual features of the interaction between ZPT2-2 and DNA. These experiments allowed us to conclude that 1) the optimal binding sequence for the N-terminal zinc finger is AGC(T), and that of the C-terminal one is CAGT; 2) multiple arrangements of the two core sites accommodate binding; and 3) the spacing between the two core sites affects the binding affinity. In light of these observations, we propose a new model for the DNA-ZPT2-2 interaction. Further, consistent with this model, a high affinity binding site for ZPT2-2 was found in the promoter region of the ZPT2-2 gene. This site may serve as a cis-element for the autoregulation of ZPT2-2 gene expression.
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PMID:The plant zinc finger protein ZPT2-2 has a unique mode of DNA interaction. 1145 59

The zinc finger superfamily includes transcription factors that regulate multiple aspects of plant development and were recently shown to regulate abiotic stress tolerance. Cultivated tomato (Solanum lycopersicum Zinc Finger2 [SIZF2]) is a cysteine-2/histidine-2-type zinc finger transcription factor bearing an ERF-associated amphiphilic repression domain and binding to the ACGTCAGTG sequence containing two AGT core motifs. SlZF2 is ubiquitously expressed during plant development, and is rapidly induced by sodium chloride, drought, and potassium chloride treatments. Its ectopic expression in Arabidopsis (Arabidopsis thaliana) and tomato impaired development and influenced leaf and flower shape, while causing a general stress visible by anthocyanin and malonyldialdehyde accumulation. SlZF2 enhanced salt sensitivity in Arabidopsis, whereas SlZF2 delayed senescence and improved tomato salt tolerance, particularly by maintaining photosynthesis and increasing polyamine biosynthesis, in salt-treated hydroponic cultures (125 mm sodium chloride, 20 d). SlZF2 may be involved in abscisic acid (ABA) biosynthesis/signaling, because SlZF2 is rapidly induced by ABA treatment and 35S::SlZF2 tomatoes accumulate more ABA than wild-type plants. Transcriptome analysis of 35S::SlZF2 revealed that SlZF2 both increased and reduced expression of a comparable number of genes involved in various physiological processes such as photosynthesis, polyamine biosynthesis, and hormone (notably ABA) biosynthesis/signaling. Involvement of these different metabolic pathways in salt stress tolerance is discussed.
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PMID:The Solanum lycopersicum Zinc Finger2 cysteine-2/histidine-2 repressor-like transcription factor regulates development and tolerance to salinity in tomato and Arabidopsis. 2456 91

Q-type C2H2 zinc finger proteins (ZFPs) are plant-specific DNA-binding proteins containing a conserved QALGGH motif. This study investigated the function of abiotic stress-inducible and predominantly root-expressed Triticum aestivum ZFPs (TaZFP22, TaZFP34 and TaZFP46) with a focus on TaZFP34. Expression of TaZFP34 in roots was upregulated by high salinity, dehydration, oxidative and cold stresses. Overexpression of TaZFP34 in wheat roots resulted in an increased root-to-shoot ratio, a phenomenon observed during plant adaptation to drying soil. Expression of a number of genes which are potentially involved in modulating root growth was significantly altered in the roots of TaZFP34 overexpressing lines. In particular, the transcript levels of TaRR12B, TaRR12D and TaSHY2 that are homologues of known negative regulators of root growth were significantly reduced. Expression of shoot growth-related genes, such as GA3-ox and expansins, was downregulated in the transgenic shoots. TaZFP34 bound to (C/G)AGT(G/A)-like elements in the promoters of TaZFP34 down-regulated TaRR12D and TaSHY2 and transrepressed the reporter gene expression driven by TaRR12D and TaSHY2 promoters. Expression of the above reporter genes was also repressed by TaZFP46 and TaZFP22. These data suggest that TaZFP34 is a transcriptional repressor and is involved in modulating the root-to-shoot ratio.
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PMID:Abiotic stress upregulated TaZFP34 represses the expression of type-B response regulator and SHY2 genes and enhances root to shoot ratio in wheat. 2771 81