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)

Infections of plants by the oomycete Phytophthora infestans typically result from zoospores, which develop from sporangia at cold temperatures. To help understand the relevant cold-induced signaling pathway, factors regulating the transcription of the zoosporogenesis-specific NIF (nuclear LIM-interactor-interacting factor) gene family were examined. Sequences required for inducing PinifC3 were identified by analyzing truncated and mutated promoters using the beta-glucuronidase reporter in stable transformants. A 7-nucleotide (nt) sequence located 139 bases upstream of the major transcription start point (GGACGAG) proved essential for the induction of PinifC3 when sporangia were shifted from ambient to cold temperatures. The motif, named the cold box, also conferred cold inducibility to a promoter normally activated only during sexual development. An identical motif was detected in the two other zoosporogenesis-specific NIF genes from P. infestans and three Phytophthora sojae orthologues, and a closely related sequence was found in Phytophthora ramorum orthologues. The 7-nt motif was also found in the promoters of other zoosporogenesis-induced genes. The presence of a cold box-interacting protein in nuclear extracts of P. infestans sporangia was demonstrated using electrophoretic mobility shift assays. Furthermore, zoospore release and cold box-regulated transcription were stimulated by the membrane rigidizer dimethyl sulfoxide and inhibited by the membrane fluidizer benzyl alcohol. The data therefore delineate a pathway in which sporangia perceive cold temperatures through membrane rigidity, which activates signals that drive both zoosporogenesis and cold-box-mediated transcription.
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PMID:Activation of zoosporogenesis-specific genes in Phytophthora infestans involves a 7-nucleotide promoter motif and cold-induced membrane rigidity. 1660 21

Genes involved in pathogenicity of several plant pathogens were shown to be induced at relatively cold temperatures. Loci from the fire blight pathogen Erwinia amylovora (Burrill) induced at 18 degrees C were identified using the miniTn5 transposon that contains the promoterless reporter gene gusA coding for beta-glucuronidase (GUS). Certain mutants (2.7%) expressed GUS predominantly at 18 degrees C on minimal medium plates, indicating that the transposon had been inserted downstream of a putatively thermoregulated promoter. Those mutants were further screened with a quantitative GUS fluorometric assay. A total of 21 mutants were selected: 19 mutants had a transposon insertion in temperature-dependent genetic loci, with a 2.2- to 6.3-fold induction of gusA gene expression at 18 degrees C, and two mutants with impaired growth at 18 degrees C. Some of these genetic loci encoded (i) proteins implicated in flagella biosynthesis, biotin biosynthesis, multi-drug efflux, and type II secretion protein, and (ii) proteins of unknown function.
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PMID:Identification of low-temperature-regulated genes in the fire blight pathogen Erwinia amylovora. 1669 72

1. [4-(14)C]Progesterone was administered intravenously to anaesthetized male and female New Zealand White rabbits as a single injection or as a 45-60min. infusion. 2. After a single dose about 60% of the radioactivity was recovered in 6hr., and twice as much radioactivity was present in bile as in urine. After infusion total recovery of radioactivity was only about 40% in 6hr., but the relative proportions of metabolites in bile and urine were about the same as after a single dose. 3. Bile and urine samples were hydrolysed successively by beta-glucuronidase, cold acid and hot acid. 4. In bile the major proportion of metabolites appeared in the glucuronide fraction; in urine beta-glucuronidase hydrolysis yielded the greatest amounts of ether-extractable radioactivity, but the greatest proportion of radioactivity could not be extracted by ether from an alkaline solution of the hydrolysed urine. 5. There was no apparent difference in the quantity or distribution of metabolites excreted by male and female animals.
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PMID:Steroid metabolism in the rabbit. Biliary and urinary excretion of metabolites of [4-C]progesterone. 1674 29

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

The tonoplast monosaccharide transporter (TMT) family comprises three isoforms in Arabidopsis thaliana, and TMT-green fluorescent protein fusion proteins are targeted to the vacuolar membrane. TMT promoter-beta-glucuronidase plants revealed that the TONOPLAST MONOSACCHARIDE TRANSPORTER1 (TMT1) and TMT2 genes exhibit a tissue- and cell type-specific expression pattern, whereas TMT3 is only weakly expressed. TMT1 and TMT2 expression is induced by drought, salt, and cold treatments and by sugar. During cold adaptation, tmt knockout lines accumulated less glucose and fructose compared with wild-type plants, whereas no differences were observed for sucrose. Cold adaptation of wild-type plants substantially promoted glucose uptake into isolated leaf mesophyll vacuoles. Glucose uptake into isolated vacuoles was inhibited by NH(4)(+), fructose, and phlorizin, indicating that transport is energy-dependent and that both glucose and fructose were taken up by the same carrier. Glucose import into vacuoles from two cold-induced tmt1 knockout lines or from triple knockout plants was substantially lower than into corresponding wild-type vacuoles. Monosaccharide feeding into leaf discs revealed the strongest response to sugar in tmt1 knockout lines compared with wild-type plants, suggesting that TMT1 is required for cytosolic glucose homeostasis. Our results indicate that TMT1 is involved in vacuolar monosaccharide transport and plays a major role during stress responses.
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PMID:Molecular identification and physiological characterization of a novel monosaccharide transporter from Arabidopsis involved in vacuolar sugar transport. 1715 5

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

Signaling pathways, specifically calcium and calcium-dependent protein kinase (CDPK), have been implicated in the regulation of stress and developmental signals in plants. Here, we reported the isolation and characterization of an orchid, Phalaenopsis amabilis, CDPK gene, PaCDPK1, by using the rapid amplification of cDNA ends (RACE)-PCR technique. The full length cDNA of 2,310 bp contained an open reading frame for PaCDPK1 consisting of 593 amino acid residues. Sequence alignment indicated that PaCDPK1 shared similarities with other plant CDPKs. PaCDPK1 transcripts were expressed strongly in labellum but not in leaves and roots. In addition, the PaCDPK1 gene was transcriptionally activated in response to low temperature, wounding, and pathogen infection. To identify the regulatory role of the PaCDPK1 promoter, a construct containing the PaCDPK1 promoter fused to a beta-glucuronidase (GUS) gene was transferred into Arabidopsis by Agrobacterium-mediated transformation. GUS staining revealed that PaCDPK1/GUS expression was induced by cold, wounding, and pathogen challenge in leaves and stems of transgenic Arabidopsis. These results suggested that this PaCDPK1 gene promoter could be used as an endogenous promoter for biotechnological purposes in orchids.
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PMID:PaCDPK1, a gene encoding calcium-dependent protein kinase from orchid, Phalaenopsis amabilis, is induced by cold, wounding, and pathogen challenge. 1759 67

In a phenotypic screen of plants constitutively overexpressing DOF (DNA-binding-with-one-finger) transcription factors under the control of the Cauliflower mosaic virus 35S promoter, AtDOF4;2 was identified as a gene inducing a bushy plant phenotype and potentially being involved in the regulation of phenylpropanoid metabolism in Arabidopsis. Further molecular and biochemical characterization was performed in parallel using transgenic plants with enhanced and reduced AtDOF4;2 expression. The expression pattern of AtDOF4;2 was determined by quantitative real-time polymerase chain reaction (Q-RTPCR) and through promoter-beta-glucuronidase (GUS) fusions, indicating preferential transcriptional activity in axillary buds of the flower stalk, the hypocotyls periderm and in tapetum cells. Constitutive overexpression and RNAi-mediated silencing of AtDOF4;2 caused reciprocal changes in the expression of flavonoid biosynthetic genes and the accumulation of flavonoids under cold and high-light conditions. Moreover, tapetum-specific overexpression of AtDOF4;2 led to pollen grains devoid of flavonols. In contrast to its negative influence on flavonoid biosynthesis and coincident with high expression in the periderm and tapetum, AtDOF4;2 positively influences the production of hydroxycinnamic acids in the hypocotyl and flower buds, implicating its possible importance for suberin and sporopollenin production. These data provide evidence that AtDOF4;2, influences phenylpropanoid metabolism in an environmental and tissue-specific manner.
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PMID:Transcription factor AtDOF4;2 affects phenylpropanoid metabolism in Arabidopsis thaliana. 1763 18

The transcription factors C-repeat binding factors/dehydration-responsive element binding proteins (CBFs/DREBs) control the expression of many stress-inducible genes in Arabidopsis. A cDNA clone, designated GhDREB1, was isolated from cotton (Gossypium hirsutum) by cDNA library screening. Northern blot analysis indicated that mRNA accumulation of GhDREB1 was induced by low temperatures and salt stress, but was not induced by abscisic acid (ABA) or drought stress in cotton seedlings. Transgenic tobacco (Nicotiana tabacum) plants overexpressing GhDREB1 displayed stronger chilling tolerance than wild-type plants. Their leaf chlorophyll fluorescence, net photosynthetic rate and proline concentrations were higher than those of control plants during low-temperature treatment. However, under normal growth conditions, the transgenic tobacco plants exhibited retarded growth and delayed flowering. Interestingly, GhDREB1 transcripts in cotton seedlings were negatively regulated by gibberellic acid (GA(3)) treatment. Analysis of the promoter of the GhDREB1 gene revealed the presence of one low-temperature and four gibberellin-responsive elements. Green fluorescent protein (GFP) signal intensity or beta-glucuronidase (GUS) activity driven by the GhDREB1 promoter was clearly enhanced by low temperature but repressed by GA(3). These results suggest that GhDREB1 functions as a transcription factor and plays an important role in improving cold tolerance, and also affects plant growth and development via GA(3).
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PMID:Cotton GhDREB1 increases plant tolerance to low temperature and is negatively regulated by gibberellic acid. 1780 42

Posttranscriptional processes are important for regulation of gene expression in plant mitochondria. DEAD-box proteins, which form a huge protein family with members from all kingdoms, are fundamental components in virtually all types of processes in RNA metabolism. Two members of this protein family, designated PMH1 and PMH2 (for PUTATIVE MITOCHONDRIAL RNA HELICASE), were analyzed and characterized in mitochondria of Arabidopsis (Arabidopsis thaliana). Green fluorescent protein tagging with N-terminal PMH1 and PMH2 sequences supports the mitochondrial localization of these proteins. Northern experiments, as well as histochemical beta-glucuronidase staining of transgenic plants carrying respective promoter:beta-glucuronidase fusion constructs, revealed differing transcription patterns for the two genes. In response to cold, however, transcript levels of both genes increased. Immunodetection analyses of mitochondrial protein complexes after two-dimensional blue native/urea SDS-PAGE and after fractionation on sucrose gradients strongly suggest that one or both proteins are part of RNA-dependent complexes. Cold treatment of cell cultures or solubilization of mitochondria in the presence of MgCl(2) favored the detection of high-molecular-mass complexes. This study paves the way for detailed analysis of high-molecular-mass complexes in mitochondria of higher plants.
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PMID:Two DEAD-box proteins may be part of RNA-dependent high-molecular-mass protein complexes in Arabidopsis mitochondria. 1795 54


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