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Query: EC:2.3.1.28 (
chloramphenicol acetyltransferase
)
5,100
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The 5'-flanking region of human
Cu/Zn superoxide dismutase
(SOD1) was cloned from human genomic library for the study of regulation of human SOD1 gene. We determined 3678 nucleotide sequences of 5'-flanking region of human SOD1. The putative binding sites of transcriptional factors such as NF1, Sp1, AP1, AP2, GRE, HSE and NF kappa B were found. The upstream region of this gene was analyzed by deletion and measuring the linked
chloramphenicol acetyltransferase
(
CAT
) activities. Several deletion analyses of promoter activity indicated that there were positive and negative regulatory regions. The region from -1325 bp to -1040 bp was found to have a heat shock response element.
...
PMID:Study of 5'-flanking region of human Cu/Zn superoxide dismutase. 802 98
The
Cu/Zn superoxide dismutase
(SODI) catalyzes the dismutation of superoxide radicals produced in the course of biological oxidations. When placed under the control of the rat SOD1 gene promoter and transfected into human HepG2 hepatoma cells, the activity of a
chloramphenicol acetyltransferase
reporter gene was found to increase three- to four-fold in the presence of heavy metals (cadmium, zinc and copper). Functional analysis of mutant derivatives of the SOD1 gene promoter and the use of a heterologous promoter system confirmed that the induction of the SOD1 gene by metal ions requires a metal-responsive element (MRE) located between positions -273 and -267 (GCGCGCA). It was also shown by gel mobility shift assays that an MRE binding protein is induced by the exposure of the human liver cell line HepG2 to heavy metals. These results suggest that the MRE participates in the induction of the SOD1 gene by heavy metals.
...
PMID:Heavy metal-mediated activation of the rat Cu/Zn superoxide dismutase gene via a metal-responsive element. 1051 27
Superoxide dismutase (SOD) converts superoxide radical to H(2)O(2), which is in turn broken down to water and oxygen by catalase. Thus, SOD and catalase constitute the first coordinated unit of defence against reactive oxygen species. A wide variety of chemical and environmental factors are known to induce these antioxidant enzymes. Here, we examined the effect of ginseng saponins on the induction of SOD and catalase gene expression. To explore this possibility, the upstream regulatory promoter region of
Cu/Zn superoxide dismutase
(SOD1) and catalase genes were linked to the
chloramphenicol acetyltransferase
(
CAT
) structural gene and introduced into human hepatoma HepG2 cells. Total saponin and panaxatriol did not activate the transcription of SOD1 and catalase genes but panaxadiol increased the transcription of these genes about 2-3 fold. Among the panaxadiol ginsenosides, the Rb(2) subfraction appeared to be a major inducer of SOD1 and catalase genes. The specificity of the Rb(2) effect was further confirmed by time course- and dose-dependent induction experiments. These results suggest that the panaxadiol fraction and its ginsenosides could induce the antioxidant enzymes which are important for maintaining cell viability by lowering the level of oxygen radical generated from intracellular metabolism.
...
PMID:Transcriptional activation of Cu/Zn superoxide dismutase and catalase genes by panaxadiol ginsenosides extracted from Panax ginseng. 1059 30
Cu/Zn superoxide dismutase
(SOD1) catalyzes the dismutation of superoxide radicals produced during biological oxidations and environmental stress. Here we have investigated the effect of the most toxic dioxin, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), on the promoter of the
Cu/Zn superoxide dismutase
(SOD1) gene in HepG2 and HeLa cells using the
chloramphenicol acetyltransferase
gene as a reporter. The SOD1 promoter was activated 4- to 5-fold by TCDD treatment, in a concentration-dependent manner. In addition, the level of SOD1 mRNA and the enzymatic activity of the SOD1 protein were also enhanced on exposure of the cells to TCDD. Functional analysis of the regulatory region of the SOD1 gene by deletion and point mutation, and the use of a heterologous promoter system, showed that the SOD1 gene was transactivated by TCDD via the xenobiotic-responsive element (XRE). Gel mobility shift assays also confirmed the induction and the inducible binding of a receptor-ligand complex to XRE. Yeast cells that overexpress hSOD1 appeared to be more resistant to TCDD than the wild type. These results demonstrate that SOD1 is induced by TCDD via the XRE. The induced SOD1 may accelerate the neutralization of the superoxide anion and thus reduce the oxidative damage associated with dioxin toxicity.
...
PMID:Transcriptional activation of the human Cu/Zn superoxide dismutase gene by 2,3,7,8-tetrachlorodibenzo-p-dioxin through the xenobiotic-responsive element. 1158 71