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)

Creatine kinase (EC 2.7.3.2) (CK) isoenzymes are crucial to energy metabolism, particularly in tissues with high energy requirements. Nuclear genes encode four known CK subunits: cytoplasmic muscle, cytoplasmic brain, ubiquitous mitochondrial (uMtCK), and sarcomeric mitochondrial (sMtCK). Herein, we report the isolation and complete structural characterization of the human sMtCK gene. It contains 11 exons and encompasses more than 37 kilobase pairs (kb). The sites of exon localization in the sMtCK-coding region and their precise sizes are identical with the human uMtCK gene. The translation start codon is in the third exon and lies 17 kb from the transcription start site. The human sMtCK gene is located on chromosome 5. Sequence analysis of the sMtCK genomic upstream sequences reveals a typical TATAA box within the 80 base pairs (bp) that, by transfection experiments, are sufficient to promote expression of chimeric plasmids with the chloramphenicol acetyltransferase reporter. Cis-acting sequences in a fragment containing 3360 bp of upstream sequence, the first exon, and 750 bp of the first intron are sufficient to mediate tissue-specific expression. However, these sequences only partially regulate induction of sMtCK expression in differentiating mouse myoblasts. MEF1/MYOD and MEF2 sequence motifs present in the sMtCK gene are not sufficient to regulate differentiation-specific expression. The sMtCK gene contains sequences homologous to several motifs that are shared among some nuclear genes encoding mitochondrial proteins and that may be essential for the coordinated activation of these genes during mitochondrial biogenesis.
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PMID:Regulatory element analysis and structural characterization of the human sarcomeric mitochondrial creatine kinase gene. 191 43

We have isolated and characterised the 5' region of a member of the carp myosin heavy chain gene family. Expression of this gene has previously been shown to be induced by an increase in environmental temperature and is restricted to the small-diameter white myotomal muscle fibres which are associated with growth. The whole isoform gene, including potential regulatory sequence 5' to the transcription start site and the 3' untranslated region was cloned in a lambda2001 bacteriophage vector. Studies of the structure of the 5'-end of the gene revealed high amino acid sequence similarity with translated exons 3-7 of mammalian myosin heavy chain genes indicating identical exon/intron boundaries. The overall length of the gene was however only about one half of that in mammals and birds due to shorter introns. The region 5' to the transcription unit was sequenced and revealed the presence of putative TATA and CCAAAT boxes. In order to study the regulation of expression, a series of endonuclease-generated fragments from the 5' flanking sequence were spliced to chloramphenicol acetyltransferase reporter vectors and used in cell transfection assays or direct gene injection into carp skeletal muscle. The 5' flanking region, which contains a consensus sequence known as an E-box (CANNTG) and a MEF2 binding site, was shown to improve the expression of the reporter gene in fish acclimated at 18 degrees C or 28 degrees C. Unlike the coding region, there was little similarity between the 5'-upstream sequence (promoter region) when compared with sequences flanking the 5'-end of the other myosin heavy chain genes in mammals or chicken.
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PMID:The characterisation of the 5' regulatory region of a temperature-induced myosin-heavy-chain gene associated with myotomal muscle growth in the carp. 866 10

Troponin T (TnT), like other myofibrillar proteins, is expressed as various isoforms in different muscle fibers and/or at different development stages. A recent study suggested the expression pattern of chicken fast TnT isoforms is fixed in a given cell lineage. In the present study, we isolated genomic clones of the chicken fast TnT gene to carry out molecular analysis of its expression mechanism. One of the clones, pWETNTa, contained the 5' upstream region and approximately 20 kb downstream from exon 1. We constructed promoter/upstream segments of the chicken fast TnT gene linked to the bacterial chloramphenicol acetyltransferase (CAT) gene and tested the regulatory function of the 5' upstream region by transient transfection of the gene constructs into muscle cells. We showed that a DNA segment between -264 and -44 bp from the most 5' transcriptional initiation site, which has an MEF2, and M-CAT-like element, a CArG box and two E boxes, was essential for the expression of the fast TnT gene. Furthermore, mutation of the M-CAT-like element in the segment resulted in the most serious reduction in the fast TnT promoter activity. The results suggested that the M-CAT-like element plays an important role in transcriptional regulation of the fast TnT gene. The M-CAT-like element is very similar to the M-CAT element, but in electrophoretic mobility shift assay, the factor(s) that bound to this motif was found to be different from the M-CAT binding factor (MCBF).
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PMID:Regulation of troponin T gene expression in chicken fast skeletal muscle: involvement of an M-CAT-like element distinct from the standard M-CAT. 908 92

The c-Jun amino-terminal kinases (JNKs) are a subfamily of mitogen-activated protein kinases that phosphorylate c-Jun and ATF2, and it has been postulated that phosphorylated c-Jun enhances its own expression through AP-1 sites on the c-jun promoter. In this study, we asked whether signals activating JNK regulate the c-jun promoter. Using NIH 3T3 cells expressing G protein-coupled m1 acetylcholine receptors as an experimental model, we have recently shown that the cholinergic agonist carbachol, but not platelet-derived growth factor, potently elevates JNK activity. Consistent with these findings, carbachol, but not platelet-derived growth factor, increased the activity of a c-jun promoter-driven reporter gene (for chloramphenicol acetyltransferase). However, coexpression of JNK kinase kinase (MEKK) effectively increased JNK activity, but resulted in surprisingly limited induction of the c-jun promoter. This raised the possibility that pathway(s) distinct from JNK control the c-jun promoter, and prompted us to explore which of its regulatory elements participate in transcriptional control. We observed that deletion of the 3' AP-1 site diminished chloramphenicol acetyltransferase activity in response to carbachol, but only to a limited extent. In contrast, deletion of a MEF2 site dramatically reduced expression, and deletion of both the MEF2 and 3' AP-1 sites abolished induction. Furthermore, cotransfection with MEF2C and MEF2D cDNAs potently enhanced the activity of the c-jun promoter in response to carbachol, and stimulation of m1 receptors, but not direct JNK activation, induced expression of a MEF2-responsive plasmid. Taken together, these data strongly suggest that MEF2 mediates c-jun promoter expression by G protein-coupled receptors through a yet to be identified pathway, distinct from that of JNK.
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PMID:Signaling from G protein-coupled receptors to the c-jun promoter involves the MEF2 transcription factor. Evidence for a novel c-jun amino-terminal kinase-independent pathway. 925 89

A zebrafish myosin light chain 2 cDNA clone was isolated and characterized. Sequence analysis of the clone revealed a high homology with the mammalian and avian genes encoding the fast skeletal muscle isoform, MLC2f. In situ hybridization and Northern blot hybridization analyses indicated that the zebrafish MLC2f mRNA is expressed exclusively in the fast skeletal muscle. Ontogenetically, the MLC2f mRNA appears around 16 hours postfertilization (hpf) in the first few well-formed anterior somites. At later stages, the MLC2f mRNA can also be detected in fin buds, eye muscles, and jaw muscles. To develop a useful model system for analyzing muscle gene regulation, the promoter of the zebrafish MLC2f gene was isolated and linked to the chloramphenicol acetyltransferase (CAT) reporter gene. The MLC2f/CAT chimeric constructs were analyzed by direct injection into the zebrafish skeletal muscle, and significant CAT activity was observed; in contrast, little or no CAT activity was generated from a similarly injected prolactin gene promoter/CAT gene construct. Within the 1 kb of the MLC2f promoter region, several MEF2-binding sites and E-boxes were identified, suggesting that MLC2f can be regulated by muscle transcription factors MEF2 and myogenic bHLH proteins. A 5' deletion analysis indicated that the proximal 79 nucleotides from the transcription start site, which contains a single MEF2-binding site, is sufficient to drive a high level of CAT activity in injected muscle. Internal deletion of the MEF2 element in the -79-bp construct caused an 80% decrease in CAT activity, whereas internal deletion of the same MEF2 element in a -1044-bp construct had no effect on induced CAT activity. These observations suggest that an MEF2 element is important to activate the MLC2f gene in muscle cells, and the effect of loss of the proximal MEF2 element can be compensated for by the presence of the upstream MEF2 elements. This study also demonstrated that direct injection of DNA into skeletal muscle is a valid and valuable approach to analyze muscle gene promoters in the zebrafish.
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PMID:Fast skeletal muscle-specific expression of a zebrafish myosin light chain 2 gene and characterization of its promoter by direct injection into skeletal muscle. 1002 12

We previously characterised transgenic mice in which fast-muscle-specific regulatory sequences from the human aldolase A pM promoter drive the chloramphenicol acetyltransferase gene expression. Mutation of a NF1/MEF2 binding site (M2 motif) in this promoter does not affect fibre-type specificity of the transgene but modifies its expression in a subset of fast-twitch fibres at the limb level, preferentially affecting distal limb muscles. We investigated the molecular and cellular bases of this peculiar expression pattern that provided an adequate model to characterise the mechanisms responsible for muscle positional information. By direct electrotransfer of mutated M2 construct in adult muscle, we demonstrate that positional differences in mutated M2 transgene expression are not observed when the transgene is not integrated into chromatin. Also, this transgene expression pattern does not seem to be correlated with the extent of CpG methylation in its promoter sequence. Finally, we show that positional values reflected by CAT levels are maintained in primary cultures established from different adult limb muscles, as well as in heterotopically transplanted muscles. Our results suggest that mutation of the M2 site contributes to reveal a molecular memory of fibre fate that would be set up on pM promoter during development and persist into adulthood possibly through a chromatin imprint maintained in satellite cells associated with various limb muscles.
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PMID:Mouse muscle identity: the position-dependent and fast fiber-specific expression of a transgene in limb muscles is methylation-independent and cell-autonomous. 1464 36