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)

Young pine seedlings respond to environmental stress by induced synthesis of pinosylvin, a stilbene phytoalexin. Heartwood of pine trees is characterized by a high content of pinosylvin. The formation of pinosylvin from cinnamoyl-CoA and three molecules malonyl-CoA catalysed by pinosylvin synthase is typical of the genus Pinus. Its enzyme activity not detectable in unstressed seedlings is substantially increased upon application of stimuli like UV-light or infection with the phytopathogenic fungus Botrytis cinerea. A genomic DNA library was screened with pinosylvin synthase cDNA pSP-54 as a probe. Ten clones were isolated and grouped into five subclasses according to the size of their introns. After subcloning into plasmid T7T3, four different members of the five gene subclasses were characterized by sequencing. Emphasis was put on isolating various promoters and analyzing and comparing their responsiveness. The amino acid sequences deduced from genes PST-1, PST-2, PST-3 and PST-5 shared an overall identity of more than 95%. In gene PST-5, the putative translation start site ATG was replaced by CTG. While promoter regions near the TATAA box were almost identical PST-1, PST-2 and PST-3, further upstream sequences differed substantially. Differences in promoter strength were analysed both in transgenic tobacco plants and by transient expression in tobacco protoplasts. Constructs used contained the bacterial beta-glucuronidase under the control of the promoters of pine genes PST-1, PST-2 and PST-3. Upon treatment with UV light or fungal elicitor, the promoter of PST-1 showed highest responsiveness and led to tissue-specific expression in vascular bundles. The data suggest that in pine the gene product of PST-1 is responsible for both the stress response in seedlings and pinosylvin formation in the heartwood.
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PMID:Characterization of a pine multigene family containing elicitor-responsive stilbene synthase genes. 1008 Jun 90

A method for preparing elicitor-responsive protoplasts from grapevine cells kept in suspension culture was established. The protoplasts were employed in order to perform transient gene expression experiments produced by externally added plasmids. Using the gene coding for bacterial beta-glucuronidase as the reporter gene, the transient expression under the control of various promoters of stilbene synthase genes were analyzed. The elicitor-responsiveness of promoters from grapevine genes and heterologous promoters were assayed: the grapevine stilbene synthase gene VST-1 and pine stilbene synthase genes PST-1, PST-2 and PST-3. Compared to the expression effected by the cauliflower mosaic virus 35S RNA-promoter, the stilbene synthase promoters caused a 2-5-fold increase in GUS-activity. Incubation of transformed protoplasts with fungal cell wall further stimulated the stilbene synthase promoters but not the 35S RNA-promoter. An even more pronounced differentiation between the promoters was observed when cGMP was included in the transient expression assays. Instead of treating transformed protoplasts with fungal cell wall we administered simultaneously cGMP and the plasmid to be tested. The cGMP-responsive increase was (a) specific concerning the nucleotide applied, (b) characteristic of grapevine protoplasts, and (c) not seen with shortened promoter-GUS constructs or GUS under the control of the 35S RNA-promoter. The highest cGMP-dependent response to stress was shown by the promoter of the grapevine stilbene synthase gene VST-1.
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PMID:Grapevine protoplasts as a transient expression system for comparison of stilbene synthase genes containing cGMP-responsive promoter elements. 1034 40