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 (retinol) is required for the normal mucociliary differentiation of respiratory epithelium. A depletion of vitamin A promotes squamous cell metaplasia. To understand how vitamin A suppresses squamous cell differentiation, the expression of a squamous cell differentiation marker, the small proline-rich protein gene (spr1), was studied in cultured monkey tracheobronchial epithelial (TBE) cells. The expression of the spr1 gene was inhibited about 40 fold by retinol. The mRNA levels of the spr1 gene started to decline within 6 h of retinol treatment and reached a minimum level after 7 days. The inhibition by retinol was concentration dependent and did not require concurrent protein synthesis. The inhibition of the spr1 mRNA by retinol was not due to a decrease in the transcription rate of its gene but due to a decrease in its stability, as determined by nuclear run-on assays and mRNA half-life measurement, respectively. This result was further supported by a DNA transfection study using a chimeric construct containing the spr1 promoter region and the chloramphenicol acetyltransferase (CAT) reporter gene. The CAT activity in transfected cells was not inhibited by retinol. These results suggest that spr1 gene expression is posttranscriptionally down-regulated by retinol.
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PMID:Expression of a squamous cell marker, the spr1 gene, is posttranscriptionally down-regulated by retinol in airway epithelium. 825 68

The small proline-rich protein gene (spr1) is a marker whose expression is frequently associated with squamous cell differentiation. We observed that the expression of the spr1 gene is strongly induced by phorbol 12-myristate 13-acetate (PMA). Both the time course result and the nuclear run-on transcriptional assay suggested that the regulation of spr1 expression by PMA is controlled at the transcriptional level. To understand the nature of this regulation, human genomic clones of the spr1 gene were isolated. DNA sequence analysis revealed that the human spr1 gene contains two exons and a single intron located within the 5'-untranslated region. An AP-1 binding site (TGAGTCA) is found at -142, and a putative cyclic AMP-responsive element (TGAGGTCA) at -597 base pairs upstream of the transcription start site. A chimeric construct containing the 5'-flanking region of the spr1 gene and the chloramphenicol acetyltransferase (CAT) reporter gene was used to transfect HeLa cells or monkey primary TBE cells. The CAT activity in transfected cells is stimulated 7.5-11-fold by PMA, and the stimulation is inhibited by a protein kinase C inhibitor or by pretreating cells with PMA to down-regulate the protein kinase C activity. The CAT activity is also stimulated 3.5-fold by dibutyryl cyclic AMP, a protein kinase A activator. The stimulations by PMA and cAMP are additive. These results suggest that protein kinase C and probably protein kinase A play important roles in regulating the transcription of the spr1 gene.
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PMID:Isolation and characterization of the human spr1 gene and its regulation of expression by phorbol ester and cyclic AMP. 838 78