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 transgenic tobacco plants have been generated that express the E. coli beta-glucuronidase (GUS) gene under control of the promoter from the rice proliferating cell nuclear antigen (PCNA, DNA polymerase auxiliary protein) gene. GUS expression detected in situ by staining with the chromogenic substrate, 5-bromo-4-chloro-3-indolyl-beta-D-glucuronide (X-Gluc), was restricted to meristems in the organs of the transgenic tobacco plants. This expression responded to the phytohormones which promote callus formation. Furthermore, in situ thymidine uptake showed that the GUS expression pattern corresponded well to the active sites of DNA synthesis. Deletion analysis of the 5' upstream sequence confined the GUS expression pattern to a fragment extending 263 bp upstream of the transcription start site of the rice PCNA gene. Thus, we have identified this fragment as a main regulatory element of the rice PCNA gene promoter.
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PMID:Upstream sequences of rice proliferating cell nuclear antigen (PCNA) gene mediate expression of PCNA-GUS chimeric gene in meristems of transgenic tobacco plants. 170 77

We have developed a system to study human cytomegalovirus (HCMV) cis-acting promoter elements within the context of the viral genome. A recombinant HCMV (RV134) containing a marker gene (beta-glucuronidase) was used to insert HCMV promoter-chloramphenicol acetyltransferase gene constructs into the viral genome between open reading frames US9 and US10. Using this system, we have studied the promoters for the early DNA polymerase gene (UL54), the early-late lower matrix phosphoprotein gene (pp65, UL83), and the true late 28-kDa structural phosphoprotein gene (pp28, UL99). Transient-expression assays demonstrated that the pp65 and pp28 promoters are activated earlier and to higher levels than typically observed with the endogenous gene. In contrast, insertion of these promoters into the viral genome resulted in kinetics which mimicked that of the endogenous genes. In addition, we have also tested a variant of the pp28 promoter (d24/26CAT) which is deleted from -609 to -41. This promoter behaved similarly to the wild-type pp28 promoter, indicating that sequences from -40 to +106 are sufficient for conferring true late kinetics. Taken together, these data demonstrate that the viral genome affords a level of regulation on HCMV gene expression that has been previously unrealized. Therefore, these experiments provide a model system for the analysis of cis-acting promoter regulatory elements in the context of the viral genome.
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PMID:Use of recombinant virus to assess human cytomegalovirus early and late promoters in the context of the viral genome. 808 94

Cell survival after DNA damage depends on specialized DNA polymerases able to perform DNA synthesis on imperfect templates. Most of these enzymes belong to the recently discovered Y-family of DNA polymerases, none of which has been previously described in plants. We report here the isolation, functional characterization and expression analysis of a plant representative of the Y-family. This polymerase, which we have termed AtPolkappa, is a homolog of Escherichia coli pol IV and human pol kappa, and thus belongs to the DinB subfamily. We purified AtPolkappa and found a template-directed DNA polymerase, endowed with limited processivity that is able to extend primer-terminal mispairs. The activity and processivity of AtPolkappa are enhanced markedly upon deletion of 193 amino acids (aa) from its carboxy (C)-terminal domain. Loss of this region also affects the nucleotide selectivity of the enzyme, leading to the incorporation of both dCTP and dTTP opposite A in the template. We detected three cDNA forms, which result from the alternative splicing of AtPOLK mRNA and have distinct patterns of expression in different plant organs. Histochemical localization of beta-glucuronidase (GUS) activity in transgenic plants revealed that the AtPOLK promoter is active in endoreduplicating cells, suggesting a possible role during consecutive DNA replication cycles in the absence of mitosis.
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PMID:Arabidopsis thaliana AtPOLK encodes a DinB-like DNA polymerase that extends mispaired primer termini and is highly expressed in a variety of tissues. 1520 Jun 44

Microsatellites are simple, tandem DNA repeats that represent unstable regions of the genome. They undergo frequent changes in tract length by base additions or deletions due to DNA polymerase slippage during replication. To characterize factors affecting the frequency of spontaneous mutations occurring in microsatellites in plants, a reporter system was used in Arabidopsis thaliana and tomato (Lycopersicon esculentum). The beta-glucuronidase (GUS) reporter system was used to measure the mutation frequency in various microsatellites (G(7), G(10), G(13), G(16), and C(16)) in somatic tissues. Our results indicate that this frequency increases with the number of repeats: a G(16) tract was almost 80-fold more mutable than a G(7) tract. Furthermore, the frequency of mutations depends on repeat orientation, as G(16) was 3-fold more mutable than C(16). The mutation rate was also found to differ markedly in Arabidopsis and tomato for an identical microsatellite. Indeed, Arabidopsis showed a 5-fold higher mutation frequency than tomato with the same G(7) reporter construct. Finally, mutation in a G(16) tract was frequent enough that mutations transmitted germinally to the next generation could be detected at a relatively high frequency.
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PMID:Length, orientation, and plant host influence the mutation frequency in microsatellites. 1742 51