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)

To examine the role of nuclear retinoic acid (RA) receptors (RARs) in the regulation of squamous differentiation in normal human epidermal keratinocytes (NHEK), we analyzed binding activity, mRNA expression, and transcriptional activity of the endogenously expressed RARs. Specific RA-binding activity eluted from size-exclusion HPLC with an apparent mol wt of 50 kilodaltons and was predominantly (greater than 95%) associated with the NHEK nuclear cell fraction. This RAR-binding activity represented in part the expression of RAR alpha and RAR gamma genes, whose transcripts were expressed in similar abundance in undifferentiated NHEK. Differentiation resulted in lower mRNA expression of RAR alpha relative to the mRNA expression of RAR gamma. Treatment of NHEK cells with 10(-6) M RA did not induce expression of RAR beta mRNA. Similarly, three squamous cell carcinoma cell lines derived from human skin and oral cavity expressed RAR alpha and RAR gamma transcripts, but not RAR beta transcripts. Transfection of NHEK with chloramphenicol acetyltransferase (CAT) reporter plasmids indicated that the endogenously expressed RARs could activate transcription through the RAR beta response element in a concentration-dependent manner with doses of 10(-9) M RA and higher. CAT expression was not activated through TRE, a palindromic thyroid hormone response element with purported RA responsiveness. The competitive binding of benzoic acid derivatives of RA to RAR correlated with the ability of each analog to suppress mRNA expression of the squamous cell markers, involucrin, type I transglutaminase, and SQ37, and to activate transcription of the RAR beta response element-CAT reporter. These results demonstrate that the control of NHEK differentiation by RA is consistent with the interaction of the retinoid with RAR and the regulation of transcription by that ligand-receptor complex.
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PMID:Retinoic acid receptors as regulators of human epidermal keratinocyte differentiation. 131 2

Genes of Pseudomonas putida strains that are capable of degrading polychlorinated biphenyls were cloned in the plasmid vector pUC19. The resultant hybrid plasmid, pAW6194, contained cbpABCD genes on a 9.0-kb DNA fragment that was necessary for the catabolism of polychlorinated biphenyls. These genes were further subcloned on an 8.0-kb HindIII fragment of pAW540. Degradation of 3-chlorobiphenyl, 2,4-dichlorobiphenyl, and 2,4,5-trichlorobiphenyl into a chloro derivative of benzoic acid was found in Escherichia coli harboring chimeric plasmid pAW540. Expression of cbpA (biphenyl dioxygenase, 6.2 U/mg of protein) and cbpC (3-phenylcatechol dioxygenase, 611.00 U/mg of protein) genes was also found in E. coli containing the hybrid plasmid pAW540. These enzyme activities were up to 10-fold higher than those found in P. putida OU83. These results led us to conclude that cbpABCD genes of P. putida OU83 were encoded on cloned DNA and expressed in E. coli. Whether the expression of cbpABCD genes of P. putida OU83 was driven by its own promoters located on the cloned DNA or by the lacZ promoter of pUC19 was examined by subcloning a 8.0-kb DNA fragment encoding the cbpABCD genes, in both orientations, in the HindIII site of the promoter probe vector pKK232-8. The resulting recombinant plasmids, pAW560 and pAW561, expressed cbpABCD genes and conferred chloramphenicol resistance only in E. coli harboring pAW560, indicating that the expression of chloramphenicol acetyltransferase is independent of cbpABCD gene expression.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Expression, localization, and functional analysis of polychlorinated biphenyl degradation genes cbpABCD of Pseudomonas putida. 164 78

We evaluated SR11237, a retinoid X receptor (RXR)-specific compound, for its pharmacologic effects on cell differentiation in F9 embryonal carcinoma cells and rhino mouse epidermis. SR11237 can cause RXR/RXR homodimers to form and transactivate a reporter gene containing a RXR-response element. We confirmed, using nuclear receptor co-transfection assays in COS-1 cells, that SR11237 is effective at transactivating a chloramphenicol acetyltransferase reporter gene through RXRs but not retinoic acid receptors. When SR11237 was tested for its ability to modulate cell differentiation, it was inactive on F9 embryonal carcinoma cells and rhino mouse skin. Because differentiation in these systems is known to be regulated by RAR-specific compounds, such as all-trans-retinoic acid and (E)-4-[2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)-1-prope nyl benzoic acid], our results with SR11237 are compatible with the concept that classical retinoid pleiotropic responses are mediated by RXR/RAR heterodimeric nuclear receptors rather than through RXR/RXR homodimers.
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PMID:A pleiotropic response is induced in F9 embryonal carcinoma cells and rhino mouse skin by All-trans-retinoic acid, a RAR agonist but not by SR11237, a RXR-selective agonist. 817 47