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 increased production of ethylene during carnation petal senescence regulates the transcription of the GST1 gene encoding a subunit of glutathione-S-transferase. We have investigated the molecular basis for this ethylene-responsive transcription by examining the cis elements and trans-acting factors involved in the expression of the GST1 gene. Transient expression assays following delivery of GST1 5' flanking DNA fused to a beta-glucuronidase receptor gene were used to functionally define sequences responsible for ethylene-responsive expression. Deletion analysis of the 5' flanking sequences of GST1 identified a single positive regulatory element of 197 bp between -667 and -470 necessary for ethylene-responsive expression. The sequences within this ethylene-responsive region were further localized to 126 bp between -596 and -470. The ethylene-responsive element (ERE) within this region conferred ethylene-regulated expression upon a minimal cauliflower mosaic virus-35S TATA-box promoter in an orientation-independent manner. Gel electrophoresis mobility-shift assays and DNase I footprinting were used to identify proteins that bind to sequences within the ERE. Nuclear proteins from carnation petals were shown to specifically interact with the 126-bp ERE and the presence and binding of these proteins were independent of ethylene or petal senescence. DNase I footprinting defined DNA sequences between -510 and -488 within the ERE specifically protected by bound protein. An 8-bp sequence (ATTTCAAA) within the protected region shares significant homology with promoter sequences required for ethylene responsiveness from the tomato fruit-ripening E4 gene.
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PMID:An ethylene-responsive enhancer element is involved in the senescence-related expression of the carnation glutathione-S-transferase (GST1) gene. 809 Jul 46

In this paper we present the structural analysis of two tightly linked genes from the glutathione S-transferase (GST) gene family in carnation (Dianthus caryophyllus). Southern blot analysis and restriction endonuclease mapping revealed a single cloned region of the carnation genome was highly homologous to the previously characterized ethylene-responsive GST mRNA expressed in flower petals during senescence. Nucleotide sequencing of this region revealed the presence of two tandemly arranged genes designated GST1 and GST2. Comparison of the nucleotide sequences of the cloned genomic region with the previously characterized GST cDNA clone pSR8 revealed that GST1 contains the entire transcription unit in 10 exons interrupted by 9 introns. The transcription unit of GST2 was found to be very similar to GST1 with complete conservation of intron position. In addition, the length and nucleotide sequences of the two genes' introns were highly conserved. GST2 was not completely represented by the cloned genomic region, missing the 3' portion of the transcription unit. Primer extension analysis indicated a single transcriptional start site for transcripts which accumulate in senescing carnation petals. The 5'-flanking sequences of GST1 and GST2 were compared and regions of homology and divergence identified. These upstream sequences were compared with other plant ethylene-responsive genes and GST genes and several sequence motifs of potential importance in the regulation of GST expression were identified. A chimeric gene constructed between -1457 bp of the 5'-flanking DNA of GST1 and the coding region of beta-glucuronidase was found to confer ethylene-inducible expression in flower petals following delivery of the construct into tissue by particle bombardment.
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PMID:Characterization of an ethylene-responsive glutathione S-transferase gene cluster in carnation. 849 18

A novel Arabidopsis mutant has been identified with constitutive expression of GST1-GUS using plants with a pathogen-responsive reporter transgene containing the beta-glucuronidase (GUS) coding region driven by the GST1 promoter. The recessive mutant, called agd2 (aberrant growth and death2), has salicylic acid (SA)-dependent increased resistance to virulent and avirulent strains of the bacterial pathogen Pseudomonas syringae, elevated SA levels, a low level of spontaneous cell death, callose deposition, and enlarged cells in leaves. The enhanced resistance of agd2 to virulent P. syringae requires the SA signaling component NONEXPRESSOR OF PR1 (NPR1). However, agd2 renders the resistance response to P. syringae carrying avrRpt2 NPR1-independent. Thus agd2 affects both an SA- and NPR1-dependent general defense pathway and an SA-dependent, NPR1-independent pathway that is active during the recognition of avirulent P. syringae. agd2 plants also fail to show a hypersensitive cell death response (HR) unless NPR1 is removed. This novel function for NPR1 is also apparent in otherwise wild-type plants: npr1 mutants show a stronger HR, while NPR1-overproducing plants show a weaker HR when infected with P. syringae carrying the avrRpm1 gene. Spontaneous cell death in agd2 is partially suppressed by npr1, indicating that NPR1 can suppress or enhance cell death depending on the cellular context. agd2 plants depleted of SA show a dramatic exacerbation of the cell-growth phenotype and increased callose deposition, suggesting a role for SA in regulating growth and this cell-wall modification. AGD2 may function in cell death and/or growth control as well as the defense response, similarly to what has been described in animals for the functions of NFkappaB.
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PMID:The Arabidopsis aberrant growth and death2 mutant shows resistance to Pseudomonas syringae and reveals a role for NPR1 in suppressing hypersensitive cell death. 1153 66