Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Germins and germin-like proteins (GLPs) constitute a large and highly diverse family of ubiquitous plant cell wall proteins. These proteins seem to be involved in many developmental stages and stress-related processes, but their exact participation in these processes generally remains obscure. In Pinus caribaea Morelet, the PcGER1 gene is expressed uniquely in embryo tissues, and encodes a GLP ionically bound to the walls of pine embryo cells maintained in 2,4-D-containing medium. We have cloned a genomic fragment including the 1520 bp 5'-upstream promoter region of PcGER1. This sequence contains, in its 1200 bp distal part, several cis elements (e.g. SEF4, 60 kDa protein, ABA RE and Dof recognition sites) present in genes responding to hormones and/or expressed in embryo or seed tissues, or during germination. The PcGER1 promoter sequence was cloned upstream of the GUS (beta-glucuronidase) reporter gene and transferred to tobacco Bright Yellow 2 (BY-2) cells via Agrobacterium tumefaciens-mediated transformation. Promoter activity and growth performances of transgenic asynchronous cell suspensions were analysed in the presence or absence of 2,4-D and/or BA. Optimal growth, maximum cell-wall yield and PcGER1 promoter activity were observed in the presence of 2,4-D and BA at day 4, the end of the exponential growth phase where 70-75% cells have a 2C DNA content. Analysis of promoter activity during the cell cycle in an aphidicoline-synchronized culture suggested that the expression is maximum in G1 cells. We also showed that under optimal growth conditions, 5' promoter deletions decreased the activity of the reporter gene. We discuss the function of this gene with regards to cell growth. Accession number: The PcGER1 promoter sequence was submitted to the genbank database under the accession number AY077704.
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PMID:Cloning of a pine germin-like protein (GLP) gene promoter and analysis of its activity in transgenic tobacco Bright Yellow 2 cells. 1265 44

Abscisic acid (ABA) regulates many aspects of plant growth and development, yet many ABA response mutants present only subtle phenotypic defects, especially in the absence of stress. By contrast, the ABA-insensitive8 (abi8) mutant, isolated on the basis of ABA-resistant germination, also displays severely stunted growth, defective stomatal regulation, altered ABA-responsive gene expression, delayed flowering, and male sterility. The stunted growth of the mutant is not rescued by gibberellin, brassinosteroid, or indoleacetic acid application and is not attributable to excessive ethylene response, but supplementing the medium with Glc improves viability and root growth. In addition to exhibiting Glc-dependent growth, reflecting decreased expression of sugar-mobilizing enzymes, abi8 mutants are resistant to Glc levels that induce developmental arrest of wild-type seedlings. Studies of genetic interactions demonstrate that ABA hypersensitivity conferred by the ABA-hypersensitive1 mutation or overexpression of ABI3 or ABI5 does not suppress the dwarfing and Glc dependence caused by abi8 but partially suppresses ABA-resistant germination. By contrast, the ABA-resistant germination of abi8 is epistatic to the hypersensitivity caused by ethylene-insensitive2 (ein2) and ein3 mutations, yet ABI8 appears to act in a distinct Glc response pathway from these EIN loci. ABI8 encodes a protein with no domains of known function but belongs to a small plant-specific protein family. Database searches indicate that it is allelic to two dwarf mutants, elongation defective1 and kobito1, previously shown to disrupt cell elongation, cellulose synthesis, vascular differentiation, and root meristem maintenance. The cell wall defects appear to be a secondary effect of the mutations because Glc treatment restores root growth and vascular differentiation but not cell elongation. Although the ABI8 transcript accumulates in all tested plant organs in both wild-type and ABA response mutants, an ABI8-beta-glucuronidase fusion protein is localized primarily to the elongation zone of roots, suggesting substantial post-transcriptional regulation of ABI8 accumulation. This localization pattern is sufficient to complement the mutation, indicating that ABI8 acts either at very low concentrations or over long distances within the plant body.
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PMID:The Arabidopsis thaliana ABSCISIC ACID-INSENSITIVE8 encodes a novel protein mediating abscisic acid and sugar responses essential for growth. 1474 75

The beta-glucosidase gene of maize (ZmGLU1) was suggested to hydrolyze cytokinin-conjugate and release free cytokinin during plant growth and development. A clone containing the upstream region of ZmGLU1 was isolated and sequenced from a maize genomic library. The full-length ZmGLU1 promoter and a series of its 5' deletions were fused to the beta-glucuronidase (GUS) reporter gene and transferred into tobacco. The GUS activity of transgenic plants was assayed at various developmental stages. The results showed that ZmGLU1 promoter-driven GUS gene had the highest expression level in the roots and that the expression of GUS gene declined during seed maturation and down to the lowest level in mature seeds. The ZmGLU1 promoter-driven GUS expression increased during seed germination, reaching a peak on day 11. The results also showed that this promoter could be inhibited by 6-BA, trans-zeatin, and NAA, but was not affected by GA(3), ABA, SA, cold, salt, drought, and submergence treatments. The histochemical staining revealed that GUS activity was located in vigorous cell division zones with dominant staining associated with vascular tissues. Deletion analysis showed that the promoter contained a putative leaf-specific and stem-specific negative regulative element and two putative enhancers.
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PMID:Isolation of a maize beta-glucosidase gene promoter and characterization of its activity in transgenic tobacco. 1677 Jun 27

To gain a better understanding of the regulatory mechanism of plant metallothionein (MT) genes, a chimeric expression unit consisting of the beta-glucuronidase (gusA) reporter gene under the control of a 1,324 bp fragment of the rice MT (ricMT) promoter was introduced into Arabidopsis via Agrobacterium tumefaciens. The strongest histochemical staining for GUS activity was observed in the cotyledons and hypocotyls of the transgenic seedlings and in the stigma, filaments and anthers of young and mature flowers, and especially in the wounded tissues of transgenic plants. In contrast, a relatively low level of reporter gene expression was seen in the young roots of transgenic seedlings and no GUS activity was detected in the stems, seeds and leaves, but GUS activity was observed in cotyledons and the first two true leaves. Promoter analysis of 5' deletions further identified several important regions responsible for organ-specific expression including roots, flowers and wound induction, light and ABA, Cu and Zn responses. These findings demonstrate that a 1,324 bp fragment of the rice MT promoter performs a complicated transcriptional regulation with clearly functional regions in a model plant, and provide an important insight into the transcriptional regulation mechanisms that operate the temporal- and spatial-specific expression and stress responses of the rice MT gene. These results suggest that the ricMT promoter and its functional regions are potentially useful in genetic engineering of plants to express the desired genes whose products are preferentially needed in roots, flowers and wound induction.
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PMID:The GUS reporter-aided analysis of the promoter activities of a rice metallothionein gene reveals different regulatory regions responsible for tissue-specific and inducible expression in transgenic Arabidopsis. 1714 14

Abscisic acid (ABA) is an important phytohormone that plays a critical role in seed development, dormancy, and stress tolerance. 9-cis-Epoxycarotenoid dioxygenase is the key enzyme controlling ABA biosynthesis and stress tolerance. In this study, we investigated the effect of ectopic expression of another ABA biosynthesis gene, ABA2 (or GLUCOSE INSENSITIVE 1 [GIN1]) encoding a short-chain dehydrogenase/reductase in Arabidopsis (Arabidopsis thaliana). We show that ABA2-overexpressing transgenic plants with elevated ABA levels exhibited seed germination delay and more tolerance to salinity than wild type when grown on agar plates and/or in soil. However, the germination delay was abolished in transgenic plants showing ABA levels over 2-fold higher than that of wild type grown on 250 mm NaCl. The data suggest that there are distinct mechanisms underlying ABA-mediated inhibition of seed germination under diverse stress. The ABA-deficient mutant aba2, with a shorter primary root, can be restored to normal root growth by exogenous application of ABA, whereas transgenic plants overexpressing ABA2 showed normal root growth. The data reflect that the basal levels of ABA are essential for maintaining normal primary root elongation. Furthermore, analysis of ABA2 promoter activity with ABA2::beta-glucuronidase transgenic plants revealed that the promoter activity was enhanced by multiple prolonged stresses, such as drought, salinity, cold, and flooding, but not by short-term stress treatments. Coincidently, prolonged drought stress treatment led to the up-regulation of ABA biosynthetic and sugar-related genes. Thus, the data support ABA2 as a late expression gene that might have a fine-tuning function in mediating ABA biosynthesis through primary metabolic changes in response to stress.
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PMID:Ectopic expression of ABSCISIC ACID 2/GLUCOSE INSENSITIVE 1 in Arabidopsis promotes seed dormancy and stress tolerance. 1718 33

We are examining various plant-based systems to produce enzymes for the treatment of human lysosomal storage disorders. Constitutive expression of the gene encoding the human lysosomal enzyme, alpha-L-iduronidase (IDUA; EC 3.2.1.76) in leaves of transgenic tobacco plants resulted in low-enzyme activity, and the protein appeared to be subject to proteolysis. Toward enhancing production of this recombinant enzyme in vegetative tissues, transgenic tobacco plants were generated to co-express a CaMV35S:Chamaecyparis nootkatensis Abscisic Acid Insensitive3 (CnABI3) gene construct, along with the human gene construct. The latter contained regulatory sequences of the Phaseolus vulgaris arcelin 5-I gene (5'-flanking, signal-peptide-encoding, and 3'-flanking regions). Ectopic synthesis of the CnABI3 protein led to the transactivation of the arcelin promoter and accordingly high activity (e.g., 25,000 pmol/min/mg total soluble protein) and levels of recombinant IDUA mRNA and protein were induced in leaves of transgenic tobacco, particularly in the presence of 150-200 microM S-(+)-ABA. Synthesis of human IDUA containing a carboxy-terminal ER retention (SEKDEL) sequence was also inducible by ABA in leaves co-transformed with the CnABI3 gene. As compared to the natural S-(+)-ABA, two persistent ABA analogues, (+)-8' acetylene ABA and (+)-8'methylene ABA, led to greater levels of beta-glucuronidase (GUS) reporter activities in leaves co-expressing the CnABI3 gene and a vicilin:GUS chimeric gene. In contrast, (+)-8' acetylene ABA and natural ABA appeared to be equally effective in stimulating the CnABI3-induced expression of an arcelin:GUS gene, and of the human IDUA gene, the latter also driven by arcelin-gene-regulatory sequences. Various stress-related treatments, particularly high concentrations of NaCl, had an even greater effect than ABA in promoting accumulation of human IDUA in co-transformed tobacco leaves. This strategy provides the means of enhancing the yields of recombinant proteins in transgenic plant vegetative tissues and potentially in cultured plant cells. The human recombinant protein can be readily induced in the presence of chemicals such as NaCl that can be added to cell cultures or even whole plants without a significant increase in production costs.
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PMID:Ectopic expression of a conifer Abscisic Acid Insensitive3 transcription factor induces high-level synthesis of recombinant human alpha-L-iduronidase in transgenic tobacco leaves. 1720 73

Within the Arabidopsis thaliana family of 21 heat stress transcription factors (Hsfs), HsfA9 is exclusively expressed in late stages of seed development. Here, we present evidence that developmental expression of HsfA9 is regulated by the seed-specific transcription factor ABSCISIC ACID-INSENSITIVE3 (ABI3). Intriguingly, ABI3 knockout lines lack detectable levels of HsfA9 transcript and protein, and further ectopic expression of ABI3 conferred the ability to accumulate HsfA9 in response to abscisic acid in transgenic plantlets. Consequently, the most abundant heat stress proteins (Hsps) in seeds (Hsp17.4-CI, Hsp17.7-CII, and Hsp101) were not detectable in the ABI3 knockout lines, but their expression could be detected in plants ectopically expressing HsfA9 in vegetative tissues. Furthermore, this seed-specific transcription factor cascade was reconstructed in transient beta-glucuronidase reporter assays in mesophyll protoplasts by showing that ABI3 could activate the HsfA9 promoter, whereas HsfA9 in turn was shown to be a potent activator on the promoters of Hsp genes. Thus, our study establishes a genetic framework in which HsfA9 operates as a specialized Hsf for the developmental expression of Hsp genes during seed maturation.
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PMID:A novel transcriptional cascade regulating expression of heat stress proteins during seed development of Arabidopsis. 1722 Jan 97

The objective of this study was to identify rice gene promoters that are specifically induced by feeding of the striped stemborer (Chilo suppressalis). Two PCR-selected cDNA subtractive libraries were constructed from the rice variety Minghui 63. Up- and down-regulated cDNAs induced by C. suppressalis feeding were arrayed on nylon membranes. After array hybridization and Northern blot analysis, a cDNA (B1-A04) encoding a putative subtilisin/chymotrypsin inhibitor was found to be rapidly and highly induced by C. suppressalis feeding, compared with mechanical wounding. The putative promoter region, spanning from -1,569 to +446 relative to the transcriptional initiation site was isolated, fused to the GUS gene (beta-glucuronidase reporter gene) and introduced by Agrobacterium-mediated transformation to rice. In non-infested plants, the GUS activity driven by this promoter fragment was detected in culms and panicles, but not in leaves and sheaths. At 6 h after insect feeding, GUS activity was significantly induced in sheaths and culms, but not in leaves. GUS activity and native B1-A04 gene were not induced by JA and ABA treatment. A serial deletion analysis revealed two regions (-1,569 to -1,166 and -1,166 to -582) that negatively regulate the gene expression in sheaths of non-infested plants but not in insect-infested plants. An electrophoretic mobility shift assay (EMSA) identified 7 DNA fragments with various binding activities with nuclear proteins from mechanically wounded, insect-infested and untreated plants, and their possible roles in gene regulation were speculated. This promoter fragment should have utility in development of insect resistant transgenic crops.
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PMID:Analysis of rice genes induced by striped stemborer (Chilo suppressalis) attack identified a promoter fragment highly specifically responsive to insect feeding. 1752 52

CBF/DREB (C-repeat binding factor/dehydration responsive element binding factor) family of transcription factors in plants is reported to be associated with regulation of gene expression under stress conditions. Here, we report the functional characterization of a DREB transcription factor, DREB1B gene from rice (Oryza sativa ssp. indica). The OsDREB1B gene was differentially regulated at the transcriptional level by osmotic stress, oxidative stress, salicylic acid, ABA, and cold. A 745 bp promoter region of OsDREB1B cDNA was fused to the beta-glucuronidase (GUS) gene and introduced via Agrobacterium tumifaciens into the genome of Arabidopsis. Histochemical analysis of GUS expression in T(2) transgenic Arabidopsis plants indicated that OsDREB1B shows stress-specific induction pattern in response to a variety of stresses like mannitol, NaCl, PEG, methyl viologen, cold, ABA, and salicylic acid. Leaf-order-dependent induction pattern of the promoter was observed in response to both cold and ABA stresses. Further, OsDREB1B cDNA was introduced into tobacco plants under the control of CaMV35S promoter to investigate the role of DREB1B product in plant stress response. Transgenic tobacco plants have shown improved seed germination, root growth, membrane stability, and 2, 2-diphenyl-1-pycrilhydrazil hydrate (DPPH) free radical scavenging activity under inhibitory concentrations of mannitol. Importantly, transgenic plants accumulated higher fresh weight under long-term osmotic stress, and also have shown retention of more water than the wild type during drought stress. Overexpression of OsDREB1B in tobacco also improved the oxidative and freezing stress tolerance of transgenic plants. In addition, tobacco plants constitutively expressing OsDREB1B have shown decreased sensitivity to tobacco streak virus infection. Constitutive expression of OsDREB1B in tobacco also induced the expression of PR genes in transgenic plants. The data obtained provide strong in vivo evidence that OsDREB1B is involved in both abiotic and biotic stress responses, and confers broad-spectrum stress tolerance to transgenic plants.
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PMID:Rice DREB1B promoter shows distinct stress-specific responses, and the overexpression of cDNA in tobacco confers improved abiotic and biotic stress tolerance. 1875 79

The promoter of the pepper pathogen-induced membrane protein gene CaPIMP1 was analyzed by an Agrobacterium-mediated transient expression assay in tobacco leaves. Several stress-related cis-acting elements (GT-1, W-box and ABRE) are located within the CaPIMP1 promoter. In tobacco leaf tissues transiently transformed with a CaPIMP1 promoter-beta-glucuronidase (GUS) gene fusion, serially 5'-deleted CaPIMP1 promoters were differentially activated by Pseudomonas syringae pv. tabaci, ethylene, methyl jasmonate, abscisic acid, and nitric oxide. The -1,193 bp region of the CaPIMP1 gene promoter sequence exhibited full promoter activity. The -417- and -593 bp promoter regions were sufficient for GUS gene activation by ethylene and methyl jasmonate treatments, respectively. However, CaPIMP1 promoter sequences longer than -793 bp were required for promoter activation by abscisic acid and sodium nitroprusside treatments. CaPIMP1 expression was activated in pepper leaves by treatment with ethylene, methyl jasmonate, abscisic acid, beta-amino-n-butyric acid, NaCl, mechanical wounding, and low temperature, but not with salicylic acid. Overexpression of CaPIMP1 in Arabidopsis conferred hypersensitivity to mannitol, NaCl, and ABA during seed germination but not during seedling development. In contrast, transgenic plants overexpressing CaPIMP1 exhibited enhanced tolerance to oxidative stress induced by methyl viologen during germination and early seedling stages. These results suggest that CaPIMP1 expression may alter responsiveness to environmental stress, as well as to pathogen infection.
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PMID:The promoter of the pepper pathogen-induced membrane protein gene CaPIMP1 mediates environmental stress responses in plants. 1893 63


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