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)

In Arabidopsis the promoter of the gene encoding S-adenosyl-L-methionine synthetase (SAM-S) Psam-1 confers expression preferentially in the vascular tissue. In search for promoters that drive expression in particular cells of the lignifying tissues in trees, we have analyzed the expression pattern conferred by the Psam-1 promoter in transgenic poplar. Histochemical analyses demonstrated beta-glucuronidase (GUS) activity mainly in phloem and cortex tissue throughout the plant, and in root tips. Fluorimetric assays showed high GUS activity in the tissues outside (phloem, cortex and cork) compared to those inside (xylem and pith) of the cambial layer. In contrast, the endogenous SAM-S activity was high in tissues inside and low in tissues outside of the cambial layer. RNA gel blot analysis demonstrated a high transcript level of the endogenous sam-s gene(s) in tissues both outside and inside the cambial layer. This indicates that the low SAM-S activity in the bark was at least partially due to translational and/or post-translational regulation of the endogenous sam-s gene(s). In dormant transgenics, the tissue specificity was conserved, but the activity levels were up to 10-fold reduced.
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PMID:Tissue-specific expression conferred by the S-adenosyl-L-methionine synthetase promoter of Arabidopsis thaliana in transgenic poplar. 903 66

N-Methyltransferases (NMTs) catalyze the three SAM dependent sequential methylation of xanthosine, producing caffeine in Coffea species. In the present work, a PCR based genome walking method was adopted to isolate and clone the promoter for the NMT gene. Inspection of the promoter sequence revealed the presence of several motifs important for the regulation of the gene expression. The whole fragment was fused to the beta-glucuronidase (gus) reporter gene and used in Agrobacterium tumefaciens mediated transformation of Nicotiana tabacum. GUS assays proved that the isolated promoter was able to direct the expression of the reporter gene in transgenic tobacco. Based on the promoter sequence, primer was designed and the genomic fragment comprising the promoter and its corresponding gene was amplified and cloned. Sequencing of one of the genomic clones revealed the presence of four exons and three introns in NMT gene. The differences in the restriction pattern among the genomic clones were studied using PCR-RFLP. This is the first report of cloning of the promoter for a gene involved in caffeine biosynthetic pathway and it opens up the possibility of studying the molecular mechanisms that regulate the production of caffeine.
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PMID:Isolation of promoter for N-methyltransferase gene associated with caffeine biosynthesis in Coffea canephora. 1604 51