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)

The expression of the nicotinic acetylcholine receptor (AChR) in vertebrate striated muscle is regulated both during development by nerve-evoked muscle activity and by local factors released or associated with the nerve ending. The expression pattern of AChR is achieved by coordinate regulation of four embryonic subunit mRNAs, alpha, beta, gamma and delta. We have taken the approach of identifying the similarities and differences among cis-acting regulatory elements of AChR genes to gain a better understanding of these mechanisms. Thus, to begin to define DNA sequences necessary for the transcriptional regulation of the mouse beta AChR gene, we have analyzed its 5'-flanking region. Primer extension and RNAase protection analyses showed that transcription initiates at one major and two minor sites, all of which are close to the translational initiation site. Using plasmids in which segments of the 5'-flanking region were linked to the bacterial chloramphenicol acetyltransferase (CAT) gene, we have demonstrated that 150 bp of the 5'-flanking region is active in C2 myotubes but not C2 myoblasts or NIH3T3 fibroblasts. This region contains a putative binding site for myoD, and when linked to CAT was transactivated by the muscle regulatory factors myoD, myogenin, and MRF4. Thus, a 150 bp sequence of the beta-subunit gene contains information necessary for developmental specificity and responsiveness to myogenic factors.
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PMID:The 5'-flanking region of the mouse muscle nicotinic acetylcholine receptor beta subunit gene promotes expression in cultured muscle cells and is activated by MRF4, myogenin and myoD. 131 51

The expression of the nicotinic acetylcholine receptor (AChR) in vertebrate striated muscle is regulated both during development and in response to nerve-evoked muscle activity. To define DNA sequences necessary for the transcriptional regulation of the mouse alpha-subunit AChR gene, we have isolated and analyzed the alpha-gene 5'-flanking region. Primer extension and RNase protection analysis showed that transcription initiates at 2 major and 12 minor sites close to the translational initiation site. Using a series of plasmids in which segments of the 5'-flanking region were linked to the bacterial chloramphenicol acetyltransferase (CAT) gene, we have defined an 86-base pair enhancer sequence that is active in C2 myotubes but not in C2 myoblasts or NIH3T3 fibroblasts. This enhancer contains three putative binding sites for myoD1, and the 5'-upstream regions linked to CAT were transactivated by the muscle regulatory factors, myoD1, and myogenin. Transactivation by MRF4 differed with the specific alpha-subunit construct tested. Whereas the alpha-subunit CAT constructs containing both the homologous as well as the heterologous myosin light chain 1 promoter were transactivated by myoD1 and myogenin, only the constructs containing their homologous promoter were transactivated by MRF4. Thus, an 86-base pair sequence of the alpha-subunit gene contains the information necessary for developmental specificity and responsiveness to myogenic factors.
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PMID:A developmental and tissue-specific enhancer in the mouse skeletal muscle acetylcholine receptor alpha-subunit gene regulated by myogenic factors. 165 1

We have isolated the gene encoding the delta subunit of the mouse skeletal muscle acetylcholine receptor (AChR) and have identified a 148-bp cis-acting region that controls cell type-specific and differentiation-dependent gene expression. The 5' flanking region of the delta subunit gene was fused to the protein-coding region of the chloramphenicol acetyltransferase (CAT) gene and gene fusions were transfected into C2 mouse skeletal muscle cells. Both transiently and stably transfected cells were assayed for CAT gene expression. Deletions from the 5' end of the mouse delta gene demonstrate that 148 bp of 5' flanking DNA is sufficient to confer cell type-specific and differentiation-dependent expression: CAT activity is present in transfected myotubes, but not in transfected 3T3 cells or 10T1/2 cells. Moreover, the level of CAT expression in myotubes transfected with constructs containing 148 bp of 5' flanking DNA from the delta subunit gene is identical to that in myotubes transfected with constructs containing 3.2 kb of 5' flanking DNA and similar to expression from the SV-40 early promoter. Increased CAT activity in myotubes is a result of an increased rate of transcription from the delta subunit promoter, since CAT RNA levels are also 35-fold more abundant in myotubes than myoblasts. In contrast, the SV-40 early promoter is similarly active in all cell types. Thus, 148 bp of 5' flanking DNA from the delta subunit gene contains all the information required for cell type-specific and differentiation-dependent expression of the AChR delta subunit.
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PMID:Isolation and characterization of the mouse acetylcholine receptor delta subunit gene: identification of a 148-bp cis-acting region that confers myotube-specific expression. 319 87

The muscle nicotinic acetylcholine receptor undergoes profound changes in abundance and distribution in response to innervation and denervation. As a start towards understanding the detailed mechanisms of acetylcholine receptor gene regulation, we have identified transcriptional regulatory regions of a receptor subunit gene. A region of genomic DNA at the 5' end of the mouse acetylcholine receptor gamma-subunit gene has been shown to promote transcription of the bacterial chloramphenicol acetyltransferase gene in a cell-type specific manner. In addition, the transcriptional activity of this fragment is developmentally regulated in mouse muscle C2C12 cells. We propose that this fragment contains transcriptional control elements of the mouse muscle acetylcholine receptor gamma-subunit gene.
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PMID:Transcriptional regulation of nicotinic acetylcholine receptor genes: identification of control elements of a gamma-subunit gene. 348 Jul 67

The 5' end and promoter region of the alpha-subunit gene of chicken muscle acetylcholine receptor was mapped and sequenced. It includes a TATA and a CAAT box and a potential Sp1-binding site. When inserted in front of the chloramphenicol acetyltransferase gene, this promoter (including 850 base pairs of upstream sequence) directed high transient chloramphenicol acetyltransferase expression in transfected mouse C2.7 myotubes but not in C2.7 myoblasts or nonmyogenic 3T6 cells.
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PMID:A 5'-flanking region of the chicken acetylcholine receptor alpha-subunit gene confers tissue specificity and developmental control of expression in transfected cells. 382 34

We have isolated and analysed the 5' flanking region of the rat acetylcholine receptor (AChR) beta subunit gene and determined regulatory elements that confer muscle specificity. Deletion mapping revealed a minimal TATA-box-less promoter region containing an initiator motif. An 85-bp fragment has been shown to promote high muscle-specific expression of a chloramphenicol acetyltransferase (CAT) reporter construct upon transfection in primary muscle cells. This sequence can be functionally dissected in a basal muscle-specific promoter element carrying a M-CAT box that is flanked at the 5' end by an enhancer element with two binding sites for myogenic factors. Point mutations in the M-CAT box cause the loss of transcriptional activity of the basal promoter fragment. The enhancer activity depends on the presence of both E boxes that cooperate in a synergistic fashion. We therefore conclude that the control of muscle-specific and developmental expression of the rat AChR beta subunit gene requires both regulatory elements, the M-CAT box and two adjacent E boxes, located in close proximity to each other. Cotransfection experiments in NIH3T3 cells demonstrate that the rat AChR beta subunit gene can be transactivated by myogenic factors displaying a preference for myogenin, as well as MRF4 and myf5 compared to a clearly weaker responsiveness to MyoD1.
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PMID:Two adjacent E box elements and a M-CAT box are involved in the muscle-specific regulation of the rat acetylcholine receptor beta subunit gene. 791 88

The nicotinic acetylcholine receptor (AChR) in adult skeletal muscle is composed of alpha-, beta-, epsilon-, and delta-subunits and is localized at the neuromuscular junction; in contrast, the more diffusely distributed fetal form is composed of alpha-, beta-, gamma-, and delta-subunits. To define sequences necessary for the transcriptional regulation of the mouse epsilon-subunit gene, we sequenced and analyzed 1036 bp upstream of the transcription start site. Using deletion analysis of the 5'-flanking region linked to the bacterial chloramphenicol acetyltransferase (CAT) gene and transfection of the resulting constructs into established cell lines, we demonstrate that a 151 bp fragment exhibits cell type- and differentiation-specific promoter activity. This activity was independent of a myogenic factor putative binding site (E-box). However, transactivation experiments with recombinant myoD, myogenin, or MRF4 showed that the E-box was functional and that MRF4 preferentially transactivates the epsilon-promoter. Thus, like other AChR promoters, the proximal region of the epsilon-promoter contains information for cell type-specific and developmental regulation of CAT and can be transactivated by myogenic factors in cultured cell lines. Unlike the other AChR promoters characterized to date, epsilon-promoter function can be partially independent of myogenic factors of the helix-loop-helix class.
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PMID:Cell type- and differentiation-dependent expression from the mouse acetylcholine receptor epsilon-subunit promoter. 826 73