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)

Introduction by electroporation of different parsley (Petroselinum crispum) CHS-promoter/beta-glucuronidase(GUS)-reporter constructs into pea (Pisum sativum L.) protoplasts leads to a high constitutive GUS-expression and to the loss of the light-inducibility seen in the homologous parsley protoplast system. These results indicate that Unit 1 of the parsley CHS-promoter is only partly responsible for the GUS-expression detected. Instead, additional cis-elements, which are located downstream within 100 bp from the transcriptional start site, mediate the de-repression in pea protoplasts. In contrast, in yeast (Saccharomyces cerevisiae) cells, the GUS expression from the heterologous CHS/GUS construct is controlled by elements between Unit 1 and -100 bp. In both pea and yeast cells, transcription factors different from those regulating UV-responsiveness in parsley, are probably mediating the constitutive expression from the heterologous construct. The results with pea protoplasts imply that protoplastation of pea leaf cells itself induces de-repression as a result of stress to the protoplasts. This notion was strengthened by the finding that mRNA levels of the endogenous chalcone synthase were drastically increased as the result of the protoplastation procedure.
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PMID:Transcriptional activation of the parsley chalcone synthase promoter in heterologous pea and yeast systems. 1058 Feb 82

Agrobacterium tumefaciens-induced plant tumors accumulate considerable concentrations of free auxin. To determine possible mechanisms by which high auxin concentrations are maintained, we examined the pattern of auxin and flavonoid distribution in plant tumors. Tumors were induced in transformants of Trifolium repens (L.), containing the beta-glucuronidase ( GUS)-fused auxin-responsive promoter ( GH3) or chalcone synthase ( CHS2) genes, and in transformants of Arabidopsis thaliana (L.) Heynh., containing the GUS-fused synthetic auxin response element DR5. Expression of GH3::GUS and DR5::GUS was strong in proliferating metabolically active tumors, thus suggesting high free-auxin concentrations. Immunolocalization of total auxin with indole-3-acetic acid antibodies was consistent with GH3::GUS expression indicating the highest auxin concentration in the tumor periphery. By in situ staining with diphenylboric acid 2-aminoethyl ester, by thin-layer chromatography, reverse-phase high-performance liquid chromatography, and two-photon laser-scanning microscopy spectrometry, tumor-specific flavones, isoflavones and pterocarpans were detected, namely 7,4'-dihydroxyflavone (DHF), formononetin, and medicarpin. DHF was the dominant flavone in high free-auxin-accumulating stipules of Arabidopsis leaf primordia. Flavonoids were localized at the sites of strongest auxin-inducible CHS2::GUS expression in the tumor that was differentially modulated by auxin in the vascular tissue. CHS mRNA expression changes corresponded to the previously analyzed auxin concentration profile in tumors and roots of tumorized Ricinus plants. Application of DHF to stems, apically pretreated with alpha-naphthaleneacetic acid, inhibited GH3::GUS expression in a fashion similar to 1-N-naphthyl-phthalamic acid. Tumor, root and shoot growth was poor in inoculated tt4(85) flavonoid-deficient CHS mutants of Arabidopsis. It is concluded that CHS-dependent flavonoid aglycones are possibly endogenous regulators of the basipetal auxin flux, thereby leading to free-auxin accumulation in A. tumefaciens-induced tumors. This, in turn, triggers vigorous proliferation and vascularization of the tumor tissues and suppresses their further differentiation.
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PMID:Flavonoid-related regulation of auxin accumulation in Agrobacterium tumefaciens-induced plant tumors. 1452 49

Transgenic Arabidopsis thaliana plants were constructed by introduction of a fusion of the gene for beta-glucuronidase (GUS) to the CHS-A gene, which is one of the two genes for chalcone synthase that are actively expressed in the floral organs of petunia. The expression of the fusion gene CHS-A::GUS was low in transgenic Arabidopsis plantlets, but it was enhanced when plantlets or detached leaves were transferred to a medium that contained 0.3 molar sucrose, glucose, or fructose. No enhancement was observed when plantlets were transferred to a medium that contained 0.3 molar mannitol. Measurements of cellular levels of sugars revealed a tight linkage between the level of expression of the CHS-A::GUS gene and the level of accumulation of exogenously supplied sugars, in particular sucrose. The parallelism between the organ-specific accumulation of sugar and the organ-specific expression of the CHS-A::GUS gene was also observed in petunia and A. thaliana plants grown under normal conditions in soil. The consensus sequences for sugar responses, such as boxes II and III in members of the family of sporamin genes from the sweet potato, were found in the promoter region of the CHS-A gene that was used for fusion to the GUS gene. It is suggested that the expression of the CHS-A gene is regulated by sugars, as is the expression of other sugar-responsive genes, such as the genes for sporamin. A putative common mechanism for the control of expression of "sugar-related" genes, including the CHS-A gene, is discussed.
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PMID:Sugar-Dependent Expression of the CHS-A Gene for Chalcone Synthase from Petunia in Transgenic Arabidopsis. 1666 65