Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.31 (beta-glucuronidase)
 7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The GCN4 motif, a cis-element that is highly conserved in the promoters of cereal seed storage protein genes, plays a central role in controlling endosperm-specific expression. This motif is the recognition site for a basic leucine zipper transcriptional factor that belongs to the group of maize Opaque-2 (O2)-like proteins. Five different basic leucine zipper cDNA clones, designated RISBZ1-5, have been isolated from a rice seed cDNA library. The predicted gene products can be divided into two groups based on their amino acid sequences. Although all the RISBZ proteins are able to interact with the GCN4 motif, only RISBZ1 is capable of activating (more than 100-fold expression) the expression of a reporter gene under a minimal promoter fused to a pentamer of the GCN4 motif. Loss-of-function and gain-of-function experiments using the yeast GAL4 DNA binding domain revealed that the proline-rich N-terminal domain (27 amino acids in length) is responsible for transactivation. The RISBZ1 protein is capable of forming homodimers as well as heterodimers with other RISBZ subunit proteins. RISBZ1 gene expression is restricted to the seed, where it precedes the expression of storage protein genes. When the RISBZ1 promoter was transcriptionally fused to the beta-glucuronidase reporter gene and the chimeric gene was introduced into rice, the beta-glucuronidase gene is specifically expressed in aleurone and subaleurone layer of the developing endosperm. These findings suggest that the specific expression of transcriptional activator RISBZ1 gene may determine the endosperm specificity of the storage protein genes.
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PMID:A rice functional transcriptional activator, RISBZ1, responsible for endosperm-specific expression of storage protein genes through GCN4 motif. 1113 85

The soybean (Glycine max L. Merr. cv Williams 82) genes VspA and VspB encode vacuolar glycoprotein acid phosphatases that serve as vegetative storage proteins during seed fill and early stages of seedling growth. VspB expression is activated by jasmonates (JAs) and sugars and down-regulated by phosphate and auxin. Previous promoter studies demonstrated that VspB promoter sequences between -585 and -535 mediated responses to JA, and sequences between -535 and -401 mediated responses to sugars, phosphate, and auxin. In this study, the response domains were further delineated using transient expression of VspB promoter-beta-glucuronidase constructs in tobacco protoplasts. Sequences between -536 and -484 were identified as important for phosphate responses, whereas the region from -486 to -427 mediated sugar responses. Gel-shift and deoxyribonuclease-I footprinting assays revealed four DNA-binding sites between -611 and -451 of the soybean VspB promoter: one in the JA response domain, two in the phosphate response domain, and one binding site in the sugar response domain. The sequence CATTAATTAG present in the phosphate response domain binds soybean homeodomain leucine zipper proteins, suggesting a role for these transcription factors in phosphate-modulated gene expression.
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PMID:Homeodomain leucine zipper proteins bind to the phosphate response domain of the soybean VspB tripartite promoter. 1116 Oct 37

Ubiquitination plays important roles in plant hormone signal transduction. We show that the RING finger E3 ligase, Arabidopsis thaliana SALT- AND DROUGHT-INDUCED RING FINGER1 (SDIR1), is involved in abscisic acid (ABA)-related stress signal transduction. SDIR1 is expressed in all tissues of Arabidopsis and is upregulated by drought and salt stress, but not by ABA. Plants expressing the ProSDIR1-beta-glucuronidase (GUS) reporter construct confirmed strong induction of GUS expression in stomatal guard cells and leaf mesophyll cells under drought stress. The green fluorescent protein-SDIR1 fusion protein is colocalized with intracellular membranes. We demonstrate that SDIR1 is an E3 ubiquitin ligase and that the RING finger conservation region is required for its activity. Overexpression of SDIR1 leads to ABA hypersensitivity and ABA-associated phenotypes, such as salt hypersensitivity in germination, enhanced ABA-induced stomatal closing, and enhanced drought tolerance. The expression levels of a number of key ABA and stress marker genes are altered both in SDIR1 overexpression and sdir1-1 mutant plants. Cross-complementation experiments showed that the ABA-INSENSITIVE5 (ABI5), ABRE BINDING FACTOR3 (ABF3), and ABF4 genes can rescue the ABA-insensitive phenotype of the sdir1-1 mutant, whereas SDIR1 could not rescue the abi5-1 mutant. This suggests that SDIR1 acts upstream of those basic leucine zipper family genes. Our results indicate that SDIR1 is a positive regulator of ABA signaling.
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PMID:SDIR1 is a RING finger E3 ligase that positively regulates stress-responsive abscisic acid signaling in Arabidopsis. 1757 36

A gene encoding a RING zinc finger ankyrin repeat protein (MjXB3), a putative E3 ubiquitin ligase, is highly expressed in petals of senescing four o'clock (Mirabilis jalapa) flowers, increasing >40,000-fold during the onset of visible senescence. The gene has homologues in many other species, and the Petunia homologue is strongly up-regulated in senescing Petunia corollas. Silencing the expression of this gene in Petunia, using virus-induced gene silencing, resulted in a 2 d extension in flower life. In Mirabilis, a 2 kb promoter region, 5' upstream of the MjXB3 gene, was isolated. The promoter sequence included putative binding sites for many DNA-binding proteins, including the bZIP, Myb, homeodomain-leucine zipper (HD-Zip), MADS-box, and WRKY transcription factors. The construct containing a 1 kb promoter region immediately upstream of the MjXB3 gene drove the strongest expression of the beta-glucuronidase (GUS) reporter gene in a transient expression assay. In Petunia, GUS expression under the control of this heterologous promoter fragment was specific to senescing flowers. The Mirabilis promoter GUS construct was tested in other flower species; while GUS activity in carnation petals was high during senescence, no expression was detected in three monocotyledonous flowers--daylily (Hemerocallis 'Stella d'Oro'), daffodil (Narcissus pseudonarcissus 'King Alfred'), and orchid (Dendrobium 'Emma White').
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PMID:Functional analysis of a RING domain ankyrin repeat protein that is highly expressed during flower senescence. 1805 40


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