Gene/Protein Disease Symptom Drug Enzyme Compound
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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)

Vitamin A and other retinoids profoundly inhibit morphological and biochemical features of epidermal differentiation in vivo and in vitro. To elucidate the molecular mechanisms underlying the differential expression of epidermal keratins and their regulation by retinoids, we examined retinoid-mediated changes in total protein expression, protein synthesis, mRNA expression, and transcription in cultured human keratinocytes and in squamous cell carcinoma (SCC-13) cells of epidermal origin. Our studies revealed that the epidermal keratins, K5, K6, K14, and K16, their mRNAs, and their transcripts were diminished relative to actin as a consequence of retinoic acid (RA) treatment. The effects were most pronounced in SCC-13 and were detected as early as 6 hr post-RA treatment, with enhancement over an additional 24-48 hr. Repression was also observed when 5' upstream sequences of K14 or K5 genes were used to drive expression of a chloramphenicol acetyltransferase reporter gene in SCC-13 keratinocytes. Both cell types were found to express mRNAs for the RA receptors alpha and gamma, which may be involved in the RA-mediated transcriptional changes in these cells. The rapid transcriptional changes in epidermal keratin genes were in striking contrast to the previously reported slow transcriptional changes in simple epithelial keratin genes.
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PMID:Retinoid-mediated transcriptional regulation of keratin genes in human epidermal and squamous cell carcinoma cells. 171 Dec 2

A bovine genomic library was constructed using a cosmid vector, pHC79, and bovine DNA partially digested by EcoRI. Bovine P-450(11 beta) cDNA, pcP-450(11 beta)-2 [Morohashi et al. (1987) J. Biochem. 102,559-568], was used as a probe for screening the genomic library. Ten clones carrying P-450(11 beta) genomic DNA were isolated from 8 x 10(4) colonies and classified into five groups (CB11 beta-1, CB11 beta-3, CB11 beta-7, CB11 beta-20, and CB11 beta-21) according to differences in the restriction endonuclease sites. Nucleotide sequences of amino acid coding regions of the five clones were determined by the dideoxy sequencing method using synthetic nucleotides corresponding to various parts of the cDNA as primers. The nucleotide sequences revealed that three clones, CB11 beta-1, CB11 beta-3, and CB11 beta-21, were pseudogenes. Amino acid sequences coded by the other two clones, CB11 beta-7 and CB11 beta-20, were identical with that coded by a previously described cDNA, pcP-450(11 beta)-3 [Kirita et al. (1988) J. Biochem. 104, 683-686]. The promoter regions of the five clones were introduced in front of chloramphenicol acetyltransferase (CAT) gene of pSV00CAT and used to examine P-450(11 beta) gene regulation in cultured cells. The five recombinant plasmids showed cAMP-responsive CAT activities in Y-1 cells, a cell strain derived from adrenal tumor. The induction rates of the recombinant plasmids carrying the promoters of normal genes, CB11 beta-7 and -20, were larger than those of pseudogenes, CB11 beta-1, -3, and -21. CAT activities expressed by the promoter regions of the normal genes in the presence or absence of cAMP in Y-1 cells were almost equal to that by the promoter region of human P-450(SCC) gene. Though the promoter of the P-450(SCC) gene also showed cAMP-responsive CAT activity in I-10 cells, a cell strain derived from Leyding cell tumor, P-450(11 beta) gene promoter did not express the activity in I-10 cells.
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PMID:Structural analysis of multiple bovine P-450(11 beta) genes and their promoter activities. 196 87

The chronic effect of cAMP-dependent regulation on adrenocortical steroidogenesis is known to be revealed in the stimulation of the biosynthesis of steroidogenic enzymes. P-450(SCC), one of the enzymes, catalyzes the first and the rate-limiting reaction in steroidogenesis from cholesterol and its synthesis is regulated by cAMP. In order to investigate cis-acting DNA elements of this gene in response to cAMP-dependent regulation, we have constructed a fusion gene (pSCC5.4k) by ligating the 5'-flanking and the upstream untranslated region (5.4 kb) of the human P-450(SCC) gene to the structural gene for chloramphenicol acetyltransferase (CAT) and transfected it into various culture cells including Y-1 (mouse adrenal tumor), L929 (mouse fibroblast), HTC (rat hepatoma) and Hepa-1 (mouse hepatoma). Only Y-1 cells transfected with pSCC5.4k were found to express transiently the enhanced CAT activity in response to the cAMP analogue, cyclic dibutyryl-AMP (Bt2cAMP). Primer-extension analysis of RNA prepared from the cells treated with or without Bt2cAMP showed that the enhanced CAT activity was due to an increase in the CAT mRNA and that the transcription start site, determined here with the human P-450 gene in the adrenal cortex, was correctly utilized with the fusion gene in the transient expression system. Forskolin and cholera toxin, activators of adenylate cyclase, also increased the expression of the CAT activity in the Y-1 cells. It has been demonstrated, therefore, that the cAMP-dependent regulation of the P-450(SCC) gene in adrenal cortex is faithfully reflected in the transient expression system using Y-1 cells and the fusion gene and that a cis-acting DNA element(s) in response to cAMP is present within the 5'-flanking sequence (5.4 kb) of the P-450(SCC) gene.
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PMID:The 5'-flanking region of the human P-450(SCC) gene shows responsiveness to cAMP-dependent regulation in a transient gene-expression system of Y-1 adrenal tumor cells. 283 Oct 49

A previous investigation (Matsumoto et al., J. Oral Pathol. Med., 18: 498-501, 1989) has shown that the in vitro invasion of a collagen gel by squamous cell carcinoma can be substantially augmented in the presence of fibroblasts. Therefore, we undertook a study to determine if the production of collagenase(s) by a squamous cell carcinoma cell line, UM-SCC-1, was up-regulated by fibroblasts. Cocultivation of UM-SCC-1 cells with MDA-TU-138 fibroblasts, both established from the oral cavity, resulted in a dose-dependent increase in the activity of a M(r) 92,000 gelatinase as shown by zymography. Augmented M(r) 92,000 gelatinase activity was a consequence of the stimulation of the UM-SCC-1 cells by a soluble, fibroblast-derived factor since this effect could be reproduced with fibroblast-conditioned medium but not with glutaraldehyde-fixed fibroblasts. The increased M(r) 92,000 gelatinolytic activity could be accounted for by an increase in M(r) 92,000 type IV collagenase (MMP-9) protein, as demonstrated by Western blotting for this metalloproteinase. Trypsin treatment of the fibroblast-conditioned medium abolished its ability to increase MMP-9 secretion by UM-SCC-1 cells. Furthermore, fractionation of the fibroblast-conditioned medium revealed a M(r) 3,000-10,000 soluble factor(s) which was responsible for the augmented production of MMP-9 by UM-SCC-1 cells. To determine if the increased production of MMP-9, in response to the fibroblasts, was a consequence of increased promoter activity, UM-SCC-1 cells were transiently transfected with a chloramphenicol acetyltransferase reporter driven by the MMP-9 promoter and plated on plastic or on a monolayer of MDA-TU-138 fibroblasts. A 4-5-fold stimulation of MMP-9 promoter activity was observed with UM-SCC-1 cells plated with the MDA-TU-138 fibroblasts, when compared with similarly transfected cells recultured on plastic. In conclusion, we have demonstrated that MMP-9 expression in a squamous cell carcinoma cell line is augmented by a fibroblast-derived protein(s). This finding indicates a role for stromal cells in the regulation of MMP-9 expression in squamous cell carcinoma. The ability of fibroblasts to regulate MMP-9 expression in tumor cells in vitro may explain the observation that the amount of M(r) 92,000 type IV collagenase mRNA in tumor cells is highest at the tumor:stromal interface of resected squamous cell carcinoma.
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PMID:Induction of M(r) 92,000 type IV collagenase expression in a squamous cell carcinoma cell line by fibroblasts. 785 Aug 14

We isolated the human osteopontin (hOP) gene and the 5' upstream region, and analysed its exon-intron structure and potential regulatory sequences of the promoter region in comparison with those of the mouse and porcine gene. The coding sequence is split into 7 exons which are similar to those of the mouse gene, although the hOP gene is longer than the mouse gene. The difference in length is mainly due to variations in intron 3, which is approximately 2.7-fold longer than that of the mouse OP gene. The 5' upstream region of the hOP, which is highly conserved up to nucleotide -250, contains a number of potential cis regulatory consensus sequences. A series of sequentially 5'-deleted chimeric clones was tested for the ability to stimulate chloramphenicol acetyltransferase (CAT). Initial CAT analysis demonstrated that nucleotides at positions -474 to -270, -124 to -80, and -55 to -39 contained cis-acting enhancing sequences in a human monocyte cell line, SCC-3, although the -124 to -80 region was much more active than other regions. Deletion of the sequences between -474 and -270 localized this cis region to the sequence at positions -439 to -410, whereas the deletion between -124 to -80 localized the regions to -124 to -115, and -94 to -80. Gel-shift analysis using as probes synthesized double-stranded DNA corresponding to the 10 and 15 bp region at positions -124 to -115 and -94 to -80 respectively revealed that each probe formed a major band complexed with nuclear proteins prepared from SCC-3 cells.
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PMID:Cloning and characterization of the human osteopontin gene and its promoter. 794 49