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)

The heat shock (hs) response during plant growth and development was analyzed in tobacco and Arabidopsis using chimaeric beta-glucuronidase reporter genes (hs-Gus) driven by a soybean hs promoter. Fluorimetric measurements and histochemical staining revealed high Gus activities in leaves, roots, and flowers exclusively after heat stress. The highest levels of heat-inducible expression were found in the vascular tissues. Without heat stress, a developmental induction of hs-Gus was indicated by the accumulation of high levels of Gus in transgenic tobacco seeds. There was no developmental induction of hs-Gus in Arabidopsis seeds. In situ hybridization to the RNA of the small heat shock protein gene Athsp17.6 in tissue sections revealed an expression in heat-shocked leaves but no expression in control leaves of Arabidopsis. However, a high level of constitutive expression of hs genes was detected in meristematic and provascular tissues of the Arabidopsis embryo. The developmental and tissue-specific regulation of the hs response is discussed.
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PMID:Developmental regulation and tissue-specific differences of heat shock gene expression in transgenic tobacco and Arabidopsis plants. 778 89

The genes and proteins of the HSP70 family, are involved in important processes in cells and organelles at normal temperature and after heat stress. Constitutive Hsc70 and heat-inducible Hsp70 genes are known in all organisms including plants. The goal of our present investigation was to generate an Hsp70 mutation in Arabidopsis thaliana. In a transgenic approach a heat-inducible antisense Hsp70 gene was constructed, plants were transformed and screened for lack of heat-inducible HSP70 mRNA; two such lines were further investigated. In these plants the Hsp70 gene was not induced by heat shock, and the level of HSC70 RNA was also greatly reduced. This negative antisense effect was specific for genes of the HSP70 family and the induction of mRNAs encoding the small HSP18 class of heat shock protein (HSP) was not affected. The level of HSP70/HSC70 proteins was significantly reduced in transgenic plants, but HSP18 was induced to the same level in different transgenic lines and in untransformed plants. The acquisition of thermotolerance was negatively affected in artisense plants, the survival temperature being 2 degrees C below the survival temperature of the wild type and other transgenic lines. Another major effect concerning the regulation of the endogenous heat shock transcription factor HSF was detected by testing the ability to form heterotrimers between authentic HSF and recombinant HSF-GUS (beta-glucuronidase) proteins. The shut-off time, required to turn of HSF activity during recovery from heat stress, was significantly prolonged in antisense plants compared with wild-type and other transgenic lines. Our results imply a dual role of HSP70 in plants, a protective role in thermotolerance and a regulatory effect on HSF activity and hence the autoregulation of the heat shock response.
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PMID:An Hsp70 antisense gene affects the expression of HSP70/HSC70, the regulation of HSF, and the acquisition of thermotolerance in transgenic Arabidopsis thaliana. 880 99

Organisms synthesize heat shock proteins (HSPs) in response to sublethal heat stress and concomitantly acquire increased tolerance against a subsequent, otherwise lethal, heat shock. Heat shock factor (HSF) is essential for the transcription of many HSP genes. We report the isolation of two HSF genes, HSF3 and HSF4, from an Arabidopsis cDNA library. Transgenic Arabidopsis plants were generated containing constructs that allow expression of HSF3 and HSF4 or the respective translational beta-glucuronidase (GUS) fusions. Overexpression of HSF3 or HSF3-GUS, but not of HSF4 or HSF4-GUS, causes HSP synthesis at the non-heat-shock temperature of 25 degrees C in transgenic Arabidopsis. In transgenic plants bearing HSF3/HSF3-GUS, transcription of several heat shock genes is derepressed. Electrophoretic mobility shift assays suggest that derepression of the heat shock response is mediated by HSF3/HSF3-GUS functioning as transcription factor. HSF3/HSF3-GUS-overexpressing Arabidopsis plants show an increase in basal thermotolerance, indicating the importance of HSFs and HSF-regulated genes as determinants of thermoprotective processes. Plants transgenic for HSF3/HSF3-GUS exhibit no other obvious phenotypic alterations. Derepression of HSF activity upon overexpression suggests the titration of a negative regulator of HSF3 or an intrinsic constitutive activity of HSF3. We assume that stable overexpression of HSFs may be applied to other organisms as a means of derepressing the heat shock response.
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PMID:HSF3, a new heat shock factor from Arabidopsis thaliana, derepresses the heat shock response and confers thermotolerance when overexpressed in transgenic plants. 964 33

We compared the expression patterns in transgenic tobacco (Nicotiana tabacum) of two chimeric genes: a translational fusion to beta-glucuronidase (GUS) and a transcriptional fusion, both with the same promoter and 5'-flanking sequences of Ha hsp17.7 G4, a small heat shock protein (sHSP) gene from sunflower (Helianthus annuus). We found that immediately after heat shock, the induced expression from the two fusions in seedlings was similar, considering chimeric mRNA or GUS protein accumulation. Surprisingly, we discovered that the chimeric GUS protein encoded by the translational fusion was mostly inactive in such conditions. We also found that this inactivation was fully reversible. Thus, after returning to control temperature, the GUS activity was fully recovered without substantial changes in GUS protein accumulation. In contrast, we did not find differences in the in vitro heat inactivation of the respective GUS proteins. Insolubilization of the chimeric GUS protein correlated with its inactivation, as indicated by immunoprecipitation analyses. The inclusion in another chimeric gene of the 21 amino-terminal amino acids from a different sHSP lead to a comparable reversible inactivation. That effect not only illustrates unexpected post-translational problems, but may also point to sequences involved in interactions specific to sHSPs and in vivo heat stress conditions.
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PMID:Reversible heat-induced inactivation of chimeric beta-glucuronidase in transgenic plants. 1201 63

Maximizing the amount of protein translated per unit mRNA is an important goal in establishing expression systems. The 5' untranslated region (5'-UTR) of mRNA is known to play an important role in determining the rate of translation. The full length 5'-UTR from the Arabidopsis thaliana heat shock protein (HSP) gene,HSPI8.2 gene, was inserted into the cloning site between the cauliflower mosaic virus 35S RNA promoter and beta-glucuronidase (GUS) gene in the pBI221 plasmid. When this construct was transfected into Nicotiana tabacum (tobacco) BY-2 protoplasts, the level of protein was about 10-fold higher than that of unmodified pB1221. The accumulation of each transcript was the same level. We also demonstrated that the 5'-UTR of the HSP18.2 gene enhances the rate of translation in stable transgenic BY-2 clones and Arabidopsis T87 protoplasts. The 5'-UTRs of the other Arabidopsis HSP genes -HSP17.4, HSP81-1,HSP81-2, andHSP81-3 - also conferred efficient translation. These 5'-UTRs ofHSP genes may be of use in increasing the expression of foreign proteins. In combination with a strong promoter, it can be used in the development of efficient protein production systems.
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PMID:5' Untranslated region of the HSP18.2 gene contributes to efficient translation in plant cells. 1623 66

The production of beta-glucuronidase (GUS) driven by the Arabidopsis small heat shock protein 18.2 promoter in liquid cultures of transgenic tobacco (Nicotiana tabacum) hairy roots is reported. Clone GD-3, showing high GUS heat induction and a moderate growth rate, was selected from 436 clones for study. Treatment of GD-3 with heat shock at 36-42 degrees C for 2 h then recovery at 27 degrees C resulted in an increase in GUS specific activity, while higher heat-shock temperatures led to a decline. These results were in accordance with the change in esterase activity, a measure of tissue viability. Using 2 h of 42 degrees C heat shock and a recovery phase at 27 degrees C, GUS specific activity increased rapidly and reached a maximum of 267.6 nmol 4-methylumbelliferyl beta-D-glucuronic acid (MU) min-1 mg-1 protein at 24 h of recovery. When tissues were continuously heated at 42 degrees C and tested without a recovery period, GUS mRNA was detectable at 2 h and peaked at 5 h, but GUS activity was not seen until 10 h and did not peak until 28 h; in addition, the maximum activity was lower than that seen after heat shock for only 30 min or 2 h, followed by recovery. This shows that recovery at normal temperature is crucial for the heat-inducible heterogeneous expression system of transgenic hairy roots. Multiple heat-shock treatments showed that this system was heat reinducible, although a gradual decline in GUS specific activity was seen in the second and third cycles.
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PMID:Heat-inducible production of beta-glucuronidase in tobacco hairy root cultures. 1695 92

Dietary glutamine has been suggested to preserve structural and functional integrity of the gut and high dose bolus glutamine has been hypothesized to protect against potentially fatal endotoxic shock, hyperthermic stress, and side effects of chemotherapy. In this study, we aimed to relate the ability of high dose oral bolus glutamine to mitigate the severe diarrhea induced by 7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxy-camptothecin (CPT-11) chemotherapy to specific cytoprotective mechanisms [heat shock response, glutathione (GSH)] in gut and tumor tissues. Female rats bearing Ward colon tumor received CPT-11 (125 mg x kg(-1) x d(-1)x 3 d) with or without an oral glutamine bolus (0.75 g/kg) administered 30 min prior to each CPT-11 dose. Glutamine reduced incidence and severity of late-onset diarrhea following CPT-11 treatment (P < 0.05) and was associated with potentially beneficial and protective responses in the colon: 1) a 3.1- to 7.2-fold increase of heat shock protein (Hsp)25,-70, and -90alpha (P < 0.05); 2) increased reduced GSH (rGSH):oxidized GSH ratio (P < 0.05); 3) prevention of upregulated activity of a key bacterial enzyme (beta-glucuronidase) in the cecal content that mediates CPT-11 intestinal toxicity (P < 0.05); and 4) increased proportions of CD3+CD8+ lymphocytes and memory CD8+ subset in mesenteric lymph nodes following CPT-11 therapy. By contrast, glutamine treatment did not alter CPT-11's antitumor activity, the amino acid concentrations, Hsp expression, or the ratio of rGSH:oxidized GSH in the tumor. Our data demonstrate a striking dichotomy in the response of tumor and host to oral glutamine administration, concurring with the concept that this nutrient may favorably alter the balance between the host and tumor.
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PMID:Bolus oral glutamine protects rats against CPT-11-induced diarrhea and differentially activates cytoprotective mechanisms in host intestine but not tumor. 1835 29

Butyrate was shown to have a preventive effect on colon cancer in vivo. Germinated barley foodstuff (GBF) was in a prebiotic stage and had the potency to attenuate mucosal inflammation and to increase fecal butyrate production in colitis. This study aimed to determine whether the GBF treatment in a colon cancer model had the potency to suppress colon cancer. After a pre-feeding of either a control or a GBF diet for two weeks, male F344 rats received subcutaneous injections of azoxymethane twice, at a dose level of 15 mg/kg body weight. The injections were administered once a week for 2 weeks (n=10/group). Four weeks after that, the number of aberrant crypt foci (ACF) and heat shock protein (HSP) 25-positive cells in colonic mucosa were observed histologically. The mRNA level of slc5a8 was evaluated by in situ hybridization. Colonic mucosal beta-catenin was determined by Western blotting. Cecal short chain fatty acids, beta-glucosidase and beta-glucuronidase were also determined. The results showed that GBF treatment significantly decreased the number of ACF and beta-catenin formations in the colonic mucosa. GBF significantly increased the production of slc5a8, which is a tumor suppressor gene, as well as the cecal butyrate content and beta-glucosidase activity. beta-glucuronidase activity remained at the same level in GBF and control subjects. The number of HSP25-positive cells in GBF was higher than that in the control group, although it did not reach significant difference. In conclusion, GBF showed anti-tumorigenicity in the AOM rat model. Changes in the colonic environment featured through the increase of butyrate production were found. Although a more detailed study is required, this study showed the promising anti-neoplastic effects of prebiotic treatment.
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PMID:Modulation of intestinal environment by prebiotic germinated barley foodstuff prevents chemo-induced colonic carcinogenesis in rats. 1881 20

Dioxin residues widely contaminate soil and agricultural products at low concentrations and may accumulate in organisms at the top of food chains owing to their physicochemical properties. In this study, we have developed novel, dioxin-inducible, reporter gene expression systems regulated by recombinant aryl hydrocarbon receptors (AhRs). The recombinant AhRs, referred to as XDVs, consist of the DNA-binding domain of the bacterial repressor protein LexA, a 90-kDa heat shock protein- and ligand-binding regulatory domain from mouse AhR, and the transactivation domain of herpes simplex virus regulatory protein VP16. Transgenic tobacco plants carrying XDVs absorb various AhR ligands, including 3-methylcholanthrene, beta-naphthoflavone and indigo from solid medium and vermiculite, and show dose- and time-dependent expression of the beta-glucuronidase reporter gene. The results clearly suggest that XDVs are functional transcription factors that respond to AhR ligands, and that the XDV-mediated reporter gene expression system is applicable to bioassays for dioxin residues in the environment.
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PMID:Recombinant aryl hydrocarbon receptors for bioassay of aryl hydrocarbon receptor ligands in transgenic tobacco plants. 1905 10

In order to find a promoter that could be influenced by temperature shift, we explored and isolated an Aspergillus oryzae gene expressed at high temperatures (37-42 degrees C) by the cDNA subtraction method. Of the 96 cDNA clones isolated from the subtraction library, one cDNA clone showed 73% identity with Aspergillus nidulans heat shock protein 30 (hsp30). Based on this, we designated the isolated gene hsp30 of A. oryzae. A. oryzae hsp30 was weakly expressed at 30 degrees C, but strongly at 40 degrees C. We showed that the promoter of this hsp30 induced heterologous gene expression at high temperatures using beta-glucuronidase (GUS) gene as a reporter. Regarding elucidation of the region essential for heat shock response, we showed that the minimum length of the promoter region that was essential for heat shock response was located between -388 and -272 (+1 indicated the first position of the translation initiation codon) of the hsp30 promoter. This promoter region harbors several putative transcription factor binding sites, including heat shock elements (HSEs), a CCAAT box, and a TATA box. Furthermore, site-directed mutagenesis of this promoter revealed that HSE1 (aTTCgtcGAAacgcccaGAAa) and HSE2 (cGAAagTTCtcGACg), located between -342 and -272 of the hsp30 promoter, were its cis-acting elements for heat shock response.
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PMID:Deletion analysis of the promoter of Aspergillus oryzae gene encoding heat shock protein 30. 1933 90


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