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

---

Query: EC:3.2.1.31 (beta-glucuronidase)
7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous results from this laboratory have demonstrated the presence of genes for phosphoenolpyruvate carboxylase and pyruvate, orthophosphate dikinase in C3 plants. The structure and light-enhanced expression of these genes is very similar to that of the genes found in the C4 plant, maize. In order to investigate whether or not the regulation of these genes is similar in C3 and C4 plants, we have constructed chimeric genes using beta-glucuronidase as a reporter gene under the control of the maize promoters of the genes for phosphoenolpyruvate carboxylase, pyruvate, orthophosphate dikinase, and the small subunit of ribulose bisphosphate carboxylase (RuBisCO). The chimeric genes were introduced into tobacco, a C3 plant. These genes were expressed primarily in leaf and stem tissue and the expression was enhanced by light. Thus, as in C4 plants, the genes are expressed in a tissue-specific and light-inducible manner in the C3 plant. Since the expression of these genes is restricted to specific cells in leaf tissue of C4 plants, we also investigated the spatial pattern of expression of the chimeric genes using histochemical analysis of beta-glucuronidase activity. High level expression of all of these genes was found in mesophyll cells. This included the small subunit of RuBisCO, which is not expressed in mesophyll cells but in bundle sheath cells in C4 plants. This report describes similarities between C3 and C4 plants in regulating the expression of these genes.
...
PMID:Expression of photosynthetic genes from the C4 plant, maize, in tobacco. 185 86

Electrical discharge particle acceleration was used to test the transient expression of numerous inducible angiosperm promoters in a gymnosperm Picea glauca (white spruce). Promoter expression was assayed in three different tissues capable of in vitro regeneration, zygotic embryos, seedlings and embryogenic callus. The promoters tested include the light-inducible Arabidopsis and soybean ribulose-1,5-bisphosphate small subunit promoters and a maize phosphoenolpyruvate carboxylase promoter; a soybean heat-shock-inducible promoter, a soybean auxin inducible promoter and a maize alcohol dehydrogenase promoter. Promoters were cloned into a promoter-less expression vector to form a promoter-beta-glucuronidase-nopaline synthase 3' fusion. A similar construct was made using the cauliflower mosaic virus 35S (CaMV 35S) promoter as a control. All promoters were expressed in white spruce embryos, yet at levels lower than CaMV 35S. In addition, in the embryos the heat-shock and the alcohol dehydrogenase promoters showed inducible expression when given the proper induction stimulus. In seedlings, expression of all promoters was lower than in the embryos and expression was only inducible with the heat-shock promoter in the cotyledons. Of the tissues tested, the expression level of all promoters was lowest in embryogenic callus. Interestingly, the expression of the beta-glucuronidase gene in embryogenic callus was restricted to the proembryonal head cells regardless of the promoter used. These results clearly demonstrate the use of particle bombardment to test the transient expression of heterologous promoters in organized tissue and the expression of angiosperm promoters in a gymnosperm.
...
PMID:Expression of inducible angiosperm promoters in a gymnosperm, Picea glauca (white spruce). 186 22

A method was developed for measuring in vivo rates of mRNA synthesis in mice by pulse-labeling with the RNA precursor [3H]orotate and then using hybridization to recover specific mRNAs. The efficiency of recovery is determined with synthetic RNAs as internal hybridization standards. The method is particularly applicable to the kidney since this organ shows a strong preferential uptake of the label. Rates of synthesis, expressed as a fraction of total RNA synthesis, were measured for the androgen-inducible mRNAs coding for beta-glucuronidase (GUS), ornithine decarboxylase (ODC), the protein coded by the RP-2 gene, and the so-called kidney androgen-regulated protein (KAP). Control mRNAs coded for beta-actin, phosphoenolpyruvate carboxykinase, and major urinary protein. Testosterone markedly increased the synthesis of the androgen-inducible mRNAs, but not the control mRNAs. Induction was not seen in mutant mice lacking functional androgen receptor protein. For GUS, ODC, and RP-2 mRNAs, the fold induction of synthesis was less than the fold induction of concentration, suggesting that mRNA stabilization also plays a part in the response to androgen. For GUS, ODC, and RP-2 mRNAs, but not KAP mRNA, induction of synthesis was rapidly reversed after testosterone removal. KAP mRNA was also exceptional in that its concentration was disproportionately high compared with its rate of synthesis, implying that it is a particularly stable mRNA.
...
PMID:mRNA synthesis rates in vivo for androgen-inducible sequences in mouse kidney. 338 33

In response to salinity or drought stress, the facultative halophyte Mesembryanthemum crystallinum will switch from C3 photosynthesis to Crassulacean acid metabolism (CAM). During this switch, the transcription rates of many genes encoding glycolytic, gluconeoagenic, and malate metabolism enzymes are increased. In particular, transcription of the Ppc1 and Gap1 genes encoding a CAM-specific isozyme of phosphoenolpyruvate carboxylase and NAD-dependent glyceraldehyde-3-phosphate dehydrogenase, respectively, is increased by salinity stress. To investigate the molecular basis of salt-induced gene regulation, we examined the Ppc1 and Gap1 promoters for cis-elements and trans-acting factors that may participate in their expression. Ppc1 or Gap1 promoter-beta-glucuronidase chimeric gene constructs containing various deletions were introduced into intact, detached M. crystallinum leaves by microprojectile bombardmen. The Ppc1 5'-flanking region contains several salt-responsive enhancer regions and one silencer region reflecting the complex regulation patterns exhibited by this promoter in vivo. A region localized between nucleotides -977 and -487 relative to the transcriptional start site appears to regulate the magnitude of salt-inducibility. In contrast, the Gap1 promoter contains a single region from -735 to -549 that confers salt-responsive gene expression. Alignment of these 5'-flanking regions reveals several common sequence motifs that resemble consensus binding sites for the Myb class of transcription factors. Electrophoretic gel mobility shift assays indicate that both the -877 to -679 region of Ppc1 and the -735 to -549 region of Gap1 form a DNA-protein complex unique to nuclear extracts from salt-stressed plants. The appearance of this DNA-protein complex upon salt stress suggests that it may participate in salt-induced transcriptional activation of Ppc1 and Gap1.
...
PMID:Identification of enhancer and silencer regions involved in salt-responsive expression of Crassulacean acid metabolism (CAM) genes in the facultative halophyte Mesembryanthemum crystallinum. 759 7

The key enzymes of photosynthetic carbon assimilation in C4 plants have evolved from C3 isoforms which were present in the C3 ancestral species. We are interested in the molecular changes responsible for the novel expression pattern of C4 genes and are focussing on phosphoenolpyruvate carboxylase (PEPCase) of the genus Flaveria. The C4 isoform of PEPCase in the C4 plant F. trinervia is encoded by the ppcA subgroup of the PEPcase gene family and is abundantly expressed in the mesophyll cells of leaves. The orthologous ppcA genes of the C3 plant F. pringlei are only weakly expressed and their transcripts do not accumulate in a leaf-specific manner but, rather, are present in all plant organs. To answer the question whether the differences in the expression levels of the ppcA genes from F. pringlei and F. trinervia are caused by changes in the 5' upstream regions of the genes or by C4-specific trans-regulatory factors, varying parts of the 5' flanking region of the ppcA1 genes of both species were fused to the beta-glucuronidase (GUS) gene and inserted in the tobacco genome. GUS expression analysis of transgenic plants revealed that the level of expression of the Flaveria ppcA1 genes are recapitulated in the heterologous C3 plant tobacco. Hence, the 5' upstream region of the ppcA1 gene of F. trinervia contains regulatory cis-elements that are responsible for the C4-specific, abundant expression of this gene. These sequences are located upstream of position -500 relative to the transcription initiation site.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Evolution of the C4 phosphoenolpyruvate carboxylase promoter of the C4 dicot Flaveria trinervia: an expression analysis in the C3 plant tobacco. 781 38

C4 plants have two carboxylases which function in photosynthesis. One, phosphoenolpyruvate carboxylase (PEPC) is localized in mesophyll cells, and the other, ribulose bisphosphate carboxylase (RuBPC) is found in bundle sheath cells. In contrast, C3 plants have only one photosynthetic carboxylase, RuBPC, which is localized in mesophyll cells. The expression of PEPC in C3 mesophyll cells is quite low relative to PEPC expression in C4 mesophyll cells. Two chimeric genes have been constructed consisting of the structural gene encoding beta-glucuronidase (GUS) controlled by two promoters from C4 (maize) photosynthetic genes: (i) the PEPC gene (pepc) and (ii) the small subunit of RuBPC (rbcS). These constructs were introduced into a C3 cereal, rice. Both chimeric genes were expressed almost exclusively in mesophyll cells in the leaf blades and leaf sheaths at high levels, and no or very little activity was observed in other cells. The expression of both genes was also regulated by light. These observations indicate that the regulation systems which direct cell-specific and light-inducible expression of pepc and rbcS in C4 plants are also present in C3 plants. Nevertheless, expression of endogenous pepc in C3 plants is very low in C3 mesophyll cells, and the cell specificity of rbcS expression in C3 plants differs from that in C4 plants. Rice nuclear extracts were assayed for DNA-binding protein(s) which interact with a cis-regulatory element in the pepc promoter. Gel-retardation assays indicate that a nuclear protein with similar DNA-binding specificity to a maize nuclear protein is present in rice.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:The promoters of two carboxylases in a C4 plant (maize) direct cell-specific, light-regulated expression in a C3 plant (rice). 792 Jul 19

The 5' flanking region of a salt-stress-inducible, CAM-specific phosphoenolpyruvate carboxylase (PEPC) gene from the facultative halophyte Mesembryanthemum crystallinum, was fused to the beta-glucuronidase (GUS) reporter gene and introduced into Nicotiana tabacum SR1. The Ppc1 promoter displayed high levels of expression in transgenic tobacco quantitatively and qualitatively similar to a full-length 35S CaMV-GUS construct. Histochemical assays revealed that the full-length Ppc1-GUS fusions expressed GUS activity in all tissues except in root tips. While tobacco is capable of utilizing the Ppc1 cis-acting regulatory regions from M. crystallinum to yield high levels of constitutive expression, this glycophyte fails to direct a stress-inducible pattern of gene expression typical of this promoter in its native, facultative halophytic host.
...
PMID:Expression of a phosphoenolpyruvate carboxylase promoter from Mesembryanthemum crystallinum is not salt-inducible in mature transgenic tobacco. 844 49

To play an essential role in C4 photosynthesis, the maize C4 phosphoenolpyruvate carboxylase gene (PPCZm1) acquired many new expression features, such as leaf specificity, mesophyll specificity, light inducibility and high activity, that distinguish the unique C4 PPC from numerous non-C4 PPC genes in maize. We present here the first investigation of the developmental, cell-specific, light and metabolic regulation of the homologous C4 PPCZm1 promoter in stable transgenic maize plants. We demonstrate that the 1.7 kb of the 5'-flanking region of the PPCZm1 gene is sufficient to direct the C4-specific expression patterns of beta-glucuronidase (GUS) activity, as a reporter, in stable transformed maize plants. In light-grown shoots, GUS expression was strongest in all developing and mature mesophyll cells in the leaf, collar and sheath. GUS activity was also detected in mesophyll cells in the outer husks of ear shoots and in the outer glumes of staminate spikelets. We did not observe histological localization of GUS activity in light- or dark-grown callus, roots, silk, developing or mature kernels, the shoot apex, prop roots, or pollen. In addition, we used the stable expressing transformants to conduct and quantify physiological induction studies. Our results indicate that the expression of the C4 PPCZm1-GUS fusion gene is mesophyll-specific and influenced by development, light, glucose, acetate and chloroplast biogenesis in transgenic maize plants. These studies suggest that the adoption of DNA regulatory elements for C4-specific gene expression is a crucial step in C4 gene evolution.
...
PMID:Mesophyll-specific, light and metabolic regulation of the C4 PPCZm1 promoter in transgenic maize. 1124

Three genes encoding phosphoenolpyruvate carboxylase were isolated from Nicotiana sylvestris and designated Nsppc1-3. Sequencing of nucleotides showed that the coding sequence and deduced amino acid sequences were highly conserved among the genes, but sequences for noncoding regions including introns and 5'-flanking regions were not conserved. Analysis of the transcript level of the genes by a combination of reverse transcriptase-PCR and restriction fragment polymorphism showed mostNsppc1 in the leaves, stems, roots, and cultured cells of N. sylvestris. beta-Glucuronidase activity was detected histochemically in mesophyll cells in leaves, lateral buds, and vascular bundles in roots of transgenic tobacco harboring a chimeric construct of the Nsppc1 promoter and the gene for beta-glucuronidase. Deletion analysis indicated the presence of a silencer-like element for basal expression in the promoter region of Nsppc1.
...
PMID:Genomic structure and promoter analysis of phosphoenolpyruvate carboxylase in a C3 plant, Nicotiana sylvestris. 1235 29

We have determined the genomic organization of two closely related phosphoenolpyruvate carboxylase genes in soybean, GmPEPC7, which is expressed at high levels in root nodules, and the housekeeping gene GmPEPC15. Their nucleotide sequences, including most introns and 5;-flanking regions within 600 bp upstream from the transcription start sites, are well conserved, suggesting that they were duplicated quite recently. To gain insights into the process of evolution of the tissue-specifically expressed GmPEPC7gene, we produced chimeric constructs carrying either the GmPEPC7or GmPEPC15promoter fused to the beta-glucuronidase gene. The expression patterns of the reporter observed in nodules that developed on transgenic hairy roots reflected the levels of mRNA levels produced by the genes in wild-type soybean plants, indicating that the GmPEPC7promoter directs nodule-specific expression. Loss-of-function experiments showed that the segment of GmPEPC7between -466 and -400, designated as the "switch region" (SR), was necessary for expression in nodules, although proteins that bind to SR were not detectable in a gel-retardation assay. Another gel-retardation assay indicated that putative nodule nuclear proteins bind specifically to the region of GmPEPC7between -400 and -318, designated as the "amplifier region" (AR). Both SR and AR have characteristic sequences that are not found in the GmPEPC15promoter. Furthermore, experiments using hybrid promoters derived from GmPEPC15demonstrated that AR confers high-level expression in nodules only in combination with SR. When wild-type soybean plants were subjected to prolonged darkness and subsequently illuminated, the level of GmPEPC7mRNA in nodules decreased and then recovered. This study suggests that the acquisition of two interdependent cis-acting elements resulted in molecular evolution of the nodule-enhanced GmPEPC7gene.
...
PMID:Regulatory regions and nuclear factors involved in nodule-enhanced expression of a soybean phosphoenolpyruvate carboxylase gene: implications for molecular evolution. 1268 74


1 2 Next >>

---