Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.31 (beta-glucuronidase)
 7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Anti-Fc gamma R IgM monoclonal antibodies (mAbs) isolated from lipopolysaccharide-stimulated spleen cells from tightskin (TSK) mice were found to be polyspecific, reacting with a wide variety of molecules, including double-stranded DNA, topoisomerase, RNA polymerase, and different collagen types. Approximately 60% of the polyspecific IgM mAbs have anti-Fc gamma R specificity. These anti-Fc gamma R mAbs induce the release of hydrolases from both azurophil and specific granules of human neutrophils. 25-45% of the total cellular content (determined in Nonidet P-40 lysates) of neutrophil elastase, 10-25% of beta-glucuronidase, and 30-50% of alkaline phosphatase was released after incubation with the mAbs. The degranulation process was accompanied by dramatic morphological changes shown by scanning and transmission electron microscopy. The release of hydrolytic enzymes stimulated by the IgM anti-Fc gamma R mAbs was inhibited by preincubation of neutrophils with Fab fragments of either anti-human Fc gamma RII (IV.3) or anti-human Fc gamma RIII (3G8) mAbs. The binding of the anti-Fc gamma R TSK mAbs to human neutrophils was inhibited by Fab fragments of mAb 3G8. However, we found that the TSK anti-Fc gamma R mAbs do not bind to human Fc gamma RII expressed in either CHO cells or the P388D1 mouse macrophage cell line. Since the enzyme release could be inhibited by Fab fragments of mAb IV.3, we suggest that the signal transduction may require Fc gamma RII activation subsequent to crosslinking of the glycan phosphatidyl inositol-anchored Fc gamma RIII-1. These data demonstrate for the first time that polyspecific autoantibodies with Fc gamma R specificity can trigger neutrophil enzyme release via human Fc gamma RIII-1 in vitro and indicate a possible role for such autoantibodies in autoimmune inflammatory processes.
 ...
PMID:IgM anti-Fc gamma R autoantibodies trigger neutrophil degranulation. 182 27

A 395 bp fragment located downstream from the soybean heat shock gene Gmhsp 17.6-L exhibits several characteristics of scaffold attachment region (SAR) sequences. It contains matrix consensus elements, a topoisomerase II binding sequence and it associates with the isolated nuclear scaffold of soybean in vitro. Chimaeric genes containing the SARL fragment either at one side (5' or 3') or at both sides of a heat shock promoter-regulated beta-glucuronidase reporter gene were constructed. A five- to nine-fold increase of heat-inducible beta-glucuronidase activity was observed in transgenic tobacco plants containing constructs with SARL fragments either at both sides or with at least one SARL copy located upstream from the reporter gene. The gene copy number is positively correlated with the level of heat-inducible reporter gene activity in these plants but positional effects are not entirely eliminated. Thus, SAR sequences may potentially be used to increase gene expression, via as yet unknown mechanisms, and to reduce adverse effects on the expression of multiple gene copies in transgenic plants.
 ...
PMID:An SAR sequence containing 395 bp DNA fragment mediates enhanced, gene-dosage-correlated expression of a chimaeric heat shock gene in transgenic tobacco plants. 851 40

Irinotecan (CPT-11) is a prodrug that is used to treat metastatic colorectal cancer. It is activated to the topoisomerase poison SN-38 by carboxylesterases. SN-38 is subsequently metabolised to its inactive glucuronide, SN-38G, which can however be reactivated to SN-38 by beta-glucuronidase. The purpose of this study was to examine the role of carboxylesterases and beta-glucuronidase in the in vitro production of SN-38 in human colorectal tumours. The production of SN-38 from CPT-11 and SN-38G was measured by HPLC in human colorectal tumour homogenates. Carboxylesterase and beta-glucuronidase activities were found to be lower in tumour tissues compared to matched normal colon mucosa samples. In colorectal tumour, beta-glucuronidase and carboxylesterase-mediated SN-38 production rates were comparable at clinically relevant concentrations of SN-38G and CPT-11, respectively. Therefore, tumour beta-glucuronidase may play a significant role in the exposure of tumours to SN-38 in vivo, particularly during prolonged infusions of CPT-11.
 ...
PMID:The relative contributions of carboxylesterase and beta-glucuronidase in the formation of SN-38 in human colorectal tumours. 1453 29

Two new MAR segments (M14 and M17) were cloned from tobacco genome. Both of the sequences contained several typical consensus sequences of MARs, which were different from the original MAR sequence, such as 90%AT-box, A-box, T-box, the base unpairing regions (BUR), autonomously replicating sequences (ARS), the consensus sequence for topoisomerase II, MAR recognition sequence (MRS), origin of replication (ORI), curved DNA motifs and ATATTT et al. To investigate the effects of these two sequences on gene expression in transgenic plants, 3 plant expression vectors were constructed with uidA gene coding beta-glucuronidase (GUS) which were flanked on one side and on both sides by the MARs we obtained. These plant expression vectors with one or two MARs were transformed into tobaccos via Agrobacterium-mediated transformation method, with the plant expression vector pCAMBIA2301 without MAR and wild type tobacco as controls. GUS histochemical staining results showed that the uidA gene expressed stably in transgenic tobaccos. Quantitative detection of GUS activity showed that the MARs could increase GUS expression levels in vivo in contrast to the controls, wherever they were flanked on one side or both sides of uidA gene. The vector ligated with MARs in the same direction on both sides of uidA could increase the GUS expression level much better than both vectors which just ligated with single MARs on one side. The former one increased the average GUS activity for 3.14 folds, but 1.56 and 2.43 folds for the latter two vectors with single MARs respectively contrasting to the pCAMBIA2301 control. But the expression differences among individual transformants were still obvious. Therefore, it was concluded that the DNA sequences we obtained in this experiment were two novel MARs and could enhance gene expression in vivo. In the meanwhile, although the numbers of the MARs typical motifs in M14 were more than in M17, especially the 90% AT box which had been considered to be the highest correlative motif with binding strength in vitro, the enhancement of gene expression was lower yet, which implied no correlation between improvement of gene expression and binding strength between MARs and nuclear matrix in vitro.
 ...
PMID:[Isolation and functional analysis of tobacco MARs]. 1646 55

DNA topoisomerase 6 (TOP6) belongs to a novel family of type II DNA topoisomerases present, other than in archaebacteria, only in plants. Here we report the isolation of full-length cDNAs encoding putative TOP6 subunits A and B from rice (Oryza sativa ssp. indica), preserving all the structural domains conserved among archaebacterial TOP6 homologs and eukaryotic meiotic recombination factor SPO11. OsTOP6A1 was predominantly expressed in prepollinated flowers. The transcript abundance of OsTOP6A2, OsTOP6A3 and OsTOP6B was also higher in prepollinated flowers and callus. The expression of OsTOP6A2, OsTOP6A3 and OsTOP6B was differentially regulated by the plant hormones, auxin, cytokinin, and abscisic acid. Yeast two-hybrid analysis revealed that the full-length OsTOP6B protein interacts with both OsTOP6A2 and OsTOP6A3, but not with OsTOP6A1. The nuclear localization of OsTOP6A3 and OsTOP6B was established by the transient expression of their beta-glucuronidase fusion proteins in onion epidermal cells. Overexpression of OsTOP6A3 and OsTOP6B in transgenic Arabidopsis plants conferred reduced sensitivity to the stress hormone, abscisic acid, and tolerance to high salinity and dehydration. Moreover, the stress tolerance coincided with enhanced induction of many stress-responsive genes in transgenic Arabidopsis plants. In addition, microarray analysis revealed that a large number of genes are expressed differentially in transgenic plants. Taken together, our results demonstrate that TOP6 genes play a crucial role in stress adaptation of plants by altering gene expression.
 ...
PMID:Overexpression of putative topoisomerase 6 genes from rice confers stress tolerance in transgenic Arabidopsis plants. 1711 42