Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.1.28 (chloramphenicol acetyltransferase)
 5,100 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

CYP19, the human aromatase cytochrome P-450 (P450arom) gene, encodes an enzyme which converts androgens to estrogens by three successive hydroxylation reactions by coupling with NADPH-cytochrome P-450 reductase. In the present study, we have characterized two cis-acting transcriptional regulatory elements of CYP19, termed as hATRE-1 (human aromatase cytochrome P-450 gene transcriptional regulatory element-1) ([sequence: see text]) and hATRE-2 ([sequence: see text]). These sequences are located between -2238 and -2214, and between -2141 and -2098 relative to the major cap site of the gene, respectively. Transient expression analysis in human BeWo choriocarcinoma cells, in which CYP19 is expressed, shows that hATRE-1 represses the expression of the bacterial chloramphenicol acetyltransferase reporter gene driven by the promoter of CYP19, whereas hATRE-2 enhances the reporter gene expression in response to 12-O-tetradecanoylphorbol 13-acetate. Electrophoretic mobility shift analysis indicates that nuclear binding factors specific to hATRE-1 are present in BeWo cells, but not in HeLa cells nor in TYK-nu cells that lack the expression of CYP19. In contrast, nuclear binding factors to hATRE-2 are present not only in BeWo cells but also in the latter two types of cells. Nevertheless, hATRE-2 does not affect the reporter gene expression in HeLa cells and TYK-nu cells. These results indicate that hATRE-1 and hATRE-2 are cis-acting transcriptional regulatory elements involving in the regulation of the cell type-specific expression of CYP19.
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PMID:Identification and characterization of cis-acting regulatory elements for the expression of the human aromatase cytochrome P-450 gene. 813 35

Aromatase cytochrome P450, a member of the cytochrome P450 gene super family, catalyzes conversion of androgens to estrogens in a form of an enzyme-complex with NADPH-cytochrome P450 reductase. Transcription of the aromatase cytochrome P450 gene (CYP19) is regulated in part by tissue-specific promoters coupled with alternative splicing mechanisms. The transcription in human placenta is governed by a promoter activity of the 5' flanking region of exon I.1, which is mapped more than 40 kb upstream from the translational start codon observed in exon II. Transient expression analyses with chimeric constructs containing the 5' flanking sequences linked to the bacterial chloramphenicol acetyltransferase (CAT) gene in human BeWo choriocarcinoma cells localized a cell-type specific enhancer element between -242 and -166 relative to the major cap site. DNase I footprinting and transient expression analyses of the enhancer element indicate that it consists of two sub-elements and that both sub-elements are necessary for the maximum enhancement of the transcription. In addition to the enhancer element, a cis-acting element important for transcriptional enhancement of the gene in response to 12-O-tetradecanoylphorbol 13-acetate in BeWo cells is localized between -2141 and -2115. A nuclear factor binding to the element is identified as NF-IL6 (also termed as LAP and C/EBP beta). Transient expression analyses using the CAT constructs containing the NF-IL6 binding sites involvement of the factor in transcriptional regulation of CYP19.
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PMID:Identification and characterization of transcriptional regulatory elements of the human aromatase cytochrome P450 gene (CYP19). 860 36

Aromatase cytochrome P450 catalyses the reaction to convert androgens to estrogens by coupling with NADPH-cytochrome P450 reductase in the endoplasmic reticulum. The human aromatase cytochrome P450 gene (CYP19) is expressed in a variety of tissues under regulation of tissue-specific promoters. Previously, we localized a cell-type specific transcriptional enhancer element between -242 and -166 relative to the major cap site of the gene, by transient expression analysis in human BeWo choriocarcinoma cells. In the present study, we demonstrate that the enhancer element consists of two subelements, element I (located between -238 and -200), and element II (located between -196 and -176) as analysed by DNase I footprinting using the nuclear extracts of BeWo cells. The gel mobility shift assay shows that each of these subelements binds specific nuclear factor(s). The transient expression of the bacterial chloramphenicol acetyltransferase gene constructs involving the subelements in BeWo cells reveals that the elements activate reporter gene expression synergistically when present together, nevertheless each of the elements by itself also has an enhancer activity. The transient expression analysis further shows that element I is responsible for the transcriptional synergism with the binding site of a nuclear factor-interleukin-6 (NF-IL-6) (also known as CCAAT enhancer/binding protein beta), which is located between -2141 and -2115 relative to the major cap site of the gene. These results suggest that the enhancer element plays important roles in sustaining the high levels of CYP19 expression in placental cells in cooperation with other cis-acting transcritional regulatory elements.
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PMID:Cooperative regulation of the human aromatase cytochrome P450 gene transcription by placenta-specific cis-acting elements. 936 92