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)

Transcriptional regulation of the interleukin-5 (IL-5) gene in T lymphocytes appears to be of central importance in the control of the eosinophilia characteristic of allergic responses and certain parasite infections. Previous studies of IL-5 gene regulation have been hampered by the lack of a transfection assay, which detects the antigen-responsive enhancer in the IL-5 promoter. Here we show that stable transfection of the Th2 clone D10.G4.1 and the T lymphoma EL4.23 with chloramphenicol acetyltransferase reporter gene constructs carrying the region to -3859 gives inducible expression with the known regulatory characteristics of the endogenous IL-5 gene. To facilitate detailed analysis of the promoter region, 3.9 kb of DNA sequence immediately up stream of the start of transcription was determined and the minimum upstream region required for inducible expression was further localized, by stable transfection studies in EL4.23 cells, to the region up to -1016. A CTF/NF1 site in the upstream enhancer at -940 to -928 was shown to be required for regulated inducible expression. Mutation of this sequence motif abolished inducibility and also prevented binding of the sequence to a nuclear protein(s). A TCATTT-containing element in the proximal promoter region was also demonstrated to be essential for inducible expression of the IL-5 gene, similar to the role of this conserved element in the transcriptional regulation of the granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL-4 genes.
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PMID:Localization of the inducible enhancer in the mouse interleukin-5 gene that is responsive to T-cell receptor stimulation. 771 77

To understand better the regulation of interleukin-5 receptor alpha-subunit (IL-5R alpha) expression, we have isolated the genomic clones of mouse IL-5R alpha (mIL-5R alpha) and analyzed the structure of the gene. The gene spans more than 35 kb and is composed of 11 exons. We found that two mRNAs encoding secreted forms of mIL-5R alpha result from differential splicing events. We identified the transcriptional start site by primer extension analysis of mIL-5R alpha mRNA. Nucleotide sequence of the 5'-flanking region contains potential binding sites for transcription factor Ap1, AP-1, GATA-1, and PU.1. About 260 bp sequence of the 5'-flanking region exhibited promoter activity when it was linked to a promoterless bacterial chloramphenicol acetyltransferase (CAT) gene. The promoter activity was seen not only in the IL-5-dependent pre-B-cell line Y16, but also in fibroblast cell line NIH-3T3. Comparison of the exon-intron boundaries of mIL-5R alpha genes with those of other members of the cytokine receptor family reveals a conserved evolutionary structure. By fluorescence in situ hybridization analysis, the mIL-5R alpha gene has been assigned to chromosome 6.
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PMID:The murine interleukin-5 receptor alpha-subunit gene: characterization of the gene structure and chromosome mapping. 817 57

In addition to a previously characterized promoter (P1), we now show the existence of a second promoter for the human IL-5Ralpha gene. Initially, a genomic region (P2) 5' upstream of human IL-5Ralpha exon 2 was cloned by an inverted PCR. The transcriptional start site was then mapped to a deoxycytidine (C) residue within P2 by analyzing cellular mRNA with both the 5' rapid amplification of cDNA end-PCR and S1 nuclease protection assays. Transfection of eosinophilic HL-60 cells with reporter gene constructs in which either P1 or P2 was linked to the bacterial chloramphenicol acetyltransferase (CAT) gene resulted in CAT expression; little or no CAT expression occurred in other myeloid and nonmyeloid cell lines. Deletion studies showed that a 66-bp region, ranging from -31 to +35, was sufficient to promote CAT expression in eosinophilic HL-60 cells. Analysis of linker-scanning mutants identified a novel 6-bp element (5' CTAATT 3') spanning -19 to -14 that was essential for P2 promoter activity. In electrophoretic mobility shift assays, a P2 region from -31 to +1 containing the unique 6-bp element, when used as a probe, formed a complex with a protein(s) that was found only in the eosinophilic cell line. This binding activity was lost upon replacement of the 6-bp element with a 6-bp linker, suggesting that this element likely serves as the binding site for an eosinophilic HL-60 cell-specific transcription factor(s). Together, these data suggest an important role for P2 promoter in the regulation of eosinophil-specific expression of the human IL-5 receptor alpha gene.
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PMID:Evidence for multiple promoters of the human IL-5 receptor alpha subunit gene: a novel 6-base pair element determines cell-specific promoter function. 954 81