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)

To explore the mechanisms regulating expression of ventricular myosin light chain 1, the human gene including 5'-flanking DNA was cloned and characterized by Southern blot and restriction mapping. A 2 kb 5'-flanking DNA was sequenced and linked to a chloramphenicol acetyltransferase reporter gene. The constructs then were transfected into cultured human and rat cardiomyocytes as well as rat aortic endothelial cells. Deletion analysis of constructs revealed that the basal promoter sequences, which were located within 62 base pairs of the cap site, could direct high levels of chloramphenicol acetyltransferase gene expression in the cardiomyocytes and endothelial cells. The region between -62 to -312 base pairs strongly repressed the chloramphenicol acetyltransferase gene expression in the cardiomyocytes and endothelial cells. Positive elements were found between -312 and -2000 base pairs of the cap site. These results are indicative, among other possibilities, that the human ventricular myosin light chain 1 gene is turned on in cardiomyocytes by the presence of trans-acting factors that are bound to upstream positive elements and is turned off in non-muscle cells by the presence of repressor-binding proteins. But this mechanism remains to be established.
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PMID:Analysis of the upstream regulatory region of human ventricular myosin light chain 1 gene. 147 18

The intergenic region between the mouse alpha-myosin heavy chain (MHC) and beta-MHC genes was analyzed in terms of its ability to drive gene expression in transgenic mice. Earlier, we reported that the entire intergenic region was sufficient to direct expression of the bacterial chloramphenicol acetyl transferase reporter gene in a tissue-specific and developmental stage-specific manner. Additional transgenic lines have been generated which include two deletions. The first deletion, alpha-3, which lacks the distal 2.5 kilobase pairs of the upstream region, is competent to direct tissue- and developmental-specific expression of the transgene. A larger deletion, in which only 138 base pairs upstream of the transcriptional start site remain, shows no chloramphenicol acetyltransferase activity in either muscle or non-muscle tissue. Tissue surveys of transgene expression indicated low levels of activity in the lung, and analyses via the polymerase chain reaction confirmed the presence of the endogenous alpha-MHC gene transcripts in this tissue. Subsequently, an alpha-MHC gene-specific riboprobe was used to detect the cognate transcripts in lung sections by in situ hybridization. The data show that, in the lung, the transcripts are localized to the thick intimal wall of the veins and venules.
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PMID:Tissue-specific regulation of the alpha-myosin heavy chain gene promoter in transgenic mice. 172 8

We have isolated three overlapping genomic clones extending over 39 kilobases (kb), which encodes the rabbit cardiac sarco(endo)plasmic reticulum Ca2(+)-ATPase gene (SERCA2). S1 nuclease mapping and primer extension analysis of the 5' end of the cardiac/slow-twitch (SERCA2a) and smooth/non-muscle (SERCA2b) mRNAs showed that both transcripts are initiated from the same transcription initiation site, located 528 base pairs (bp) upstream of the translation initiation codon AUG. The putative promoter revealed a "TATA box" like element at -24 bp and a "CAAT box" at -78 bp relative to the cap site. A number of DNA sequence elements that could bind trans-acting factors were also found within the 1.8 kb of DNA sequence upstream from the transcription initiation site. To determine the DNA sequences governing transcriptional regulation, we have stably transfected the myogenic cell line C2C12 with a plasmid containing the putative promoter and 946 bp upstream sequence of the SERCA2 gene, coupled to the chloramphenicol acetyltransferase gene. Our results show that this chimeric plasmid construct exhibits appropriate activation and coordinate expression with the endogenous SERCA2 gene during the terminal differentiation of myoblasts into myotubes, suggesting that it contains the promoter and upstream sequence elements required for the regulated expression of the SERCA2 gene.
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PMID:Characterization of rabbit cardiac sarco(endo)plasmic reticulum Ca2(+)-ATPase gene. 213 26

The role of two putative, cis-acting thyroid hormone-responsive elements, TRE1 and TRE2, located at -129 to -149 and -102 to -120, respectively, on the murine alpha-myosin heavy chain (MHC) gene, has been investigated in transgenic mice. These motifs are present in a 4.5-kilobase fragment lying upstream of the transcriptional start site of the mouse alpha-MHC gene: this fragment directs appropriate expression of a reporter gene in transgenic mice (Subramaniam, A., Jones, W. K., Gulick, J., Wert, S., Neumann, J., and Robbins, J. (1991) J. Biol. Chem. 266, 24613-24620). Here, we independently mutate the TRE1 and TRE2 elements by base substitution. The mice were analyzed for transgene expression in different muscle and non-muscle tissues including the atria and ventricles. Normal levels of transgene expression were observed in euthyroid mice carrying a mutation in TRE1. In contrast to these results, mice in which TRE2 was mutated showed reduced levels of CAT activity in both the atria and ventricles, suggesting a previously undefined role for this element in the constitutive up-regulation of the alpha-MHC gene. In hypothyroid mice carrying either of these mutations, the complete cessation of ventricular expression of the chloramphenicol acetyltransferase transcripts that takes place in the alpha-5.5 (wild type) animals did not occur.
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PMID:Transgenic analysis of the thyroid-responsive elements in the alpha-cardiac myosin heavy chain gene promoter. 844 Jul 18

Doxorubicin (Dox, adriamycin), an antineoplastic agent that can cause dilated cardiomyopathy, selectively inhibits muscle-specific gene expression in rodent cardiac muscle cells. This study shows that Dox treatment of proliferating C2 myoblasts, an established cell line from mouse skeletal muscle, completely prevents both fusion and accumulation of muscle-specific gene transcripts without significantly altering non-muscle gene transcripts. When added to high density cultures, Dox only blocked myotube formation but did not inhibit induction of muscle-specific genes. Transient transfection into C2 myoblasts showed that the transcriptional expression of chloramphenicol acetyltransferase reporter plasmids regulated by either the cardiac alpha-actin promoter or the muscle creatine kinase enhancer, but not with a viral or beta-actin promoter, was significantly diminished by Dox in a dose-dependent manner. Moreover, exposure of C2 myoblasts to Dox had a profound effect on the expression of regulatory genes critical to the myogenic differentiation program; mRNAs for MyoD and myogenin were dramatically reduced and Id mRNA was concomitantly increased. In addition, there was diminished DNA binding activity of the muscle-specific transcription factor, MEF-2. These results suggest that Dox inhibits myogenesis by preventing muscle-specific gene expression, possibly through affecting the myogenic programs controlled by muscle-specific transcription factors.
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PMID:Antineoplastic agent doxorubicin inhibits myogenic differentiation of C2 myoblasts. 844 15

The M-CAT motif is a cis-regulatory DNA sequence that is essential for muscle-specific transcription of several genes. Previously, we had shown that both muscle-specific (A1) and ubiquitous (A2) factors bind to an essential M-CAT motif in the myosin heavy chain beta gene and that the ubiquitous factor is transcriptional enhancer factor (TEF)-1. Here we report the isolation of mouse cDNAs encoding two forms (a and b) of a TEF-1-related protein, TEFR1. The TEFR1a cDNA encodes a 427-amino acid protein. The coding region of TEFR1b is identical to 1a in both nucleotide and predicted amino acid sequence except for the absence of 43 amino acids downstream of the TEA DNA-binding domain. Three TEFR1 transcripts (approximately 7, approximately 3.5, and approximately 2 kilobase pairs) are enriched in differentiated skeletal muscle (myotubes) relative to undifferentiated skeletal muscle (myoblasts) and non-muscle cells in culture. In situ hybridization analysis indicated that TEFR1 transcripts are enriched in the skeletal muscle lineage during mouse embryogenesis. Transient expression of fusion proteins of TEFR1 and the yeast GAL4 DNA-binding domain in cell lines activated the expression of chloramphenicol acetyltransferase (CAT) reporter constructs containing GAL4 binding sites, indicating that TEFR1 contains an activation domain. An anti-TEFR1 polyclonal antibody supershifted the muscle-specific M-CAT.A1 factor complex in gel mobility shift assays, suggesting that TEFR1 is a major component of this complex. Our results suggest that TEFR1 might play a role in the embryonic development of skeletal muscle in the mouse.
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PMID:cDNA cloning and characterization of murine transcriptional enhancer factor-1-related protein 1, a transcription factor that binds to the M-CAT motif. 863 87

The ryanodine receptors (RYR) are a family of intracellular Ca2+ release channels that were first identified in the terminal cistenae of the sarcoplasmic reticulum of the skeletal and cardiac muscle. Mutations within the skeletal muscle isoform were shown to cause malignant hyperthermia in swine and man. We have analysed the genomic structure of the porcine skeletal muscle ryanodine receptor and its expression using chimeric reporter gene constructs consisting of the RYR1 gene promoter and the chloramphenicol acetyltransferase gene after transfection in muscle and non-muscle cells.
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PMID:[Structure and expression of the porcine skeletal muscle ryanodine receptor gene]. 903 69