Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

A rat genomic clone containing 4.5 kilobases of 5'-flanking DNA and the first exon of the type II beta regulatory subunit (RII beta) of cAMP-dependent protein kinase was isolated, restriction mapped, and sequenced. The proximal 400-basepair promoter region was GC rich, lacked TATA/CAAT box motifs, and initiated transcription at multiple sites. Bandshifting and DNase-I footprinting experiments using this region of the RII beta promoter detected several related specific DNA-protein complexes formed using crude and fractionated nuclear extracts from rat ovary, brain, adrenal gland, and liver. All binding in these experiments mapped to a domain within the same region found to confer cAMP inducibility to a chloramphenicol acetyltransferase (CAT) reporter gene when transfected into primary cultures of rat granulosa cells. Although GC boxes (putative SP1-binding sites) and activator protein-2 (AP-2) elements were present in this functional region, and although expression vectors containing AP-2 sites conferred high levels of cAMP regulation of the CAT gene in cultured ovarian cells, neither the GC boxes nor the AP-2 sites were protected by footprint analyses or required for band shift activity of nuclear extract protein. These known regulatory elements, therefore, may be involved in functional activity of the RII beta promoter, but additional cis-acting DNA and trans-acting factors (yet to be characterized) also appear to interact with the functional promoter of the RII beta gene and regulate the hormone-specific expression of the A-kinase subunit in ovarian and neuronal cells.
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PMID:Identification and characterization of the GC-rich and cyclic adenosine 3',5'-monophosphate (cAMP)-inducible promoter of the type II beta cAMP-dependent protein kinase regulatory subunit gene. 131 46

A genomic clone of glucocerebrosidase (D-glucosyl-N-acyl-sphingosine glucohydrolase; E.C. 3.2.1.45) purified from a genomic library derived from a Balb/c mouse was analyzed by restriction mapping and nucleotide sequencing of its promoter and protein coding regions. Promoter activity was functionally assessed by ligation of a 2 kb glucocerebrosidase fragment to the protein coding segment of a bacterial neomycin resistance gene. Smaller segments of the 5' flanking sequence were then analyzed for their ability to initiate transcription of the chloramphenicol acetyltransferase reporter gene. A 319 bp Eco RI-Bgl II fragment (containing 259 bp upstream of the cDNA 5' limit) ligated to the chloramphenicol acetyltransferase open reading frame produced considerable activity.
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PMID:Molecular and functional characterization of the murine glucocerebrosidase gene. 131 75

The isolation and characterization of the rat genomic clone encoding the cholesterogenic enzyme farnesyl diphosphate (FPP) synthase is reported. The gene is localized on a 15-kilobase (kb) genomic fragment, spans approximately 12 kb and contains eight exons. Sequences containing from 3.9 kb to 132 base pairs (bp) of the putative promoter were joined to the coding region of the bacterial reporter gene chloramphenicol acetyltransferase (CAT). The CAT activities or CAT mRNA levels of the hybrid genes were determined following either transient transfections into human hepatoma HepG2 cells or stable transfections into Chinese hamster ovary cells. The transient transfections identified a 319-bp fragment that was required for a 4-fold induction in the absence of sterols. Sequence analysis of this region showed it contained five potential copies of the sterol regulatory element (SRE-1) (Smith, J.R., Osborne, T.F., Brown, M.S., Goldstein, J.L., and Gil, G. (1988) J. Biol. Chem. 263, 18480-18487) previously identified in the promoters of the 3-hydroxy-3-methyl-coenzyme A (HMG-CoA) reductase, HMG-CoA synthase, and low density lipoprotein receptor genes. Further mutational and deletion analysis of the FPP synthase promoter-CAT constructs followed by stable transfection and primer extension of the CAT mRNA levels indicated that these potential SRE-1 regulatory elements were not involved in the sterol-mediated transcriptional regulation of the gene. Our analyses have identified a 115-bp region that is required for the transcriptional induction of FPP synthase in the absence of sterols. These results suggest that the FPP synthase gene may be regulated at the transcriptional level by a different mechanism than other sterol regulated genes.
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PMID:Molecular cloning and promoter analysis of the rat liver farnesyl diphosphate synthase gene. 132 Nov 49

We have isolated a genomic clone containing the mouse neu gene. The 5' end of the mouse neu gene was localized by Southern analysis, subcloned and characterized. DNA sequence analysis revealed that the promoter region is 67% G+C-rich and lacks a TATA box, although a CAAT box is present. By sequence comparison, we identified several consensus recognition sequences for general transcription factors such as Sp1, E4TF1, AP2, OTF-1 and GCF, as well as recognition sequences for RVF, E1A and GTG, which have recently been identified in the rat neu promoter. Functional promoter activity was demonstrated by the ability of the promoter to drive transcription of the bacterial chloramphenicol acetyltransferase gene. Using a series of 5'-end deletion mutants, we have identified multiple positive and negative cis-acting elements that regulate mouse neu gene transcription.
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PMID:Cloning and characterization of the mouse neu promoter. 134 55

The 5'-flanking region of the human lactoferrin gene was isolated from a human placental genomic library. This genomic clone contains a 16-kilobase pair (kbp) insert and produces seven fragments when digested with the SacI restriction enzyme. We sequenced one of the fragments that comprises 1294 bp of the 5'-flanking sequence, 79 bp of the first exon, and 690 bp of the first intron. A major transcription start site was mapped by primer extension. The region immediately upstream from the transcription initiation site following the first exon is abundant in G and C nucleotides. In the promoter and 5'-flanking region within a 300-bp stretch (-465 to -165) of the DNA, we found a noncanonical TATA box (ATAAA), CAAT-like sequence (CAAC) and sequences homologous to the consensus SP1 binding site, Pu.1/Sp.1 binding element (PU box), two half-palindromic estrogen response elements (EREs; GGTCA), an imperfect ERE (GGTCAAGGCGATC), and a sequence resembling the chicken ovalbumin upstream promoter transcription factor (COUP-TF) binding site (GTCTCACAGGTCA). The COUP-TF binding site and the imperfect ERE shared five nucleotides (GGTCA). With the exception of the two half-palindromic EREs, the elements with very well matched sequences were also found in the corresponding positions in the mouse lactoferrin gene. The synthetic oligonucleotide, including the 26 bp of COUP/ERE sequence, was cloned before the SV40 promoter in a chloramphenicol acetyltransferase reporter construct. These chimeric plasmids were transiently transfected into human endometrium carcinoma RL95-2 cells to assess hormone responsiveness. We found that the COUP/ERE element acted as an enhancer in response to estrogen stimulation. In vitro DNase I footprinting analysis showed binding of the estrogen receptor on the imperfect ERE. In contrast to the mouse lactoferrin COUP/ERE element, COUP-TF does not interact with this element, as demonstrated by band shift assay and site-directed mutagenesis. Therefore, the molecular mechanisms of the estrogen action that govern the lactoferrin gene expression differ between mouse and human.
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PMID:Differential molecular mechanism of the estrogen action that regulates lactoferrin gene in human and mouse. 148 Jan 83

To study how the expression of the D1A dopamine receptor gene is regulated, a human genomic clone was isolated by using a rat cDNA as probe. A 2.3-kilobase genomic fragment spanning -2571 through -236 relative to the adenosine of the first methionine codon was sequenced. The gene has an intron of 116 base pairs in the 5' noncoding region, nucleotides -599 through -484 as determined by S1 mapping and reverse transcription-PCR. It has multiple transcription initiation sites located between -1061 and -1040. The promoter region lacks a TATA box and a CAAT box, is rich in G+C content, and has multiple putative binding sites for transcription factor Sp1. Thus, the promoter region of the human D1A gene has features of "housekeeping" genes. However, it also has consensus sequences for AP1 and AP2 binding sites and a putative cAMP response element. The ability of four deletion mutants of the 2.3-kilobase fragment to modulate transcription of the heterologous chloramphenicol acetyltransferase gene in the promoterless plasmid pCAT-Basic was determined. All mutants demonstrated substantial transcriptional activity in the murine neuroblastoma cell line NS20Y, which expresses the D1A gene endogenously. Transient expression assays suggested the presence of a positive modulator between nucleotides -1340 and -1102, and a negative modulator between -1730 and -1341. The four genomic fragments had no or very low transcriptional activity in NB41A3, C6, and Hep G2 cells, which are not known to express this gene. Thus, the human D1A gene belongs to the category of tissue-specific, regulated genes that have housekeeping-type promoters.
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PMID:Characterization of the 5' flanking region of the human D1A dopamine receptor gene. 155 11

A genomic clone for rat tyrosine hydroxylase (TH) was isolated and a fragment containing 503 bp upstream of the transcription start site was sequenced. The BamHI/AluI fragment was inserted into a plasmid carrying the coding sequence for bacterial chloramphenicol acetyltransferase (CAT). Another construct with the 5' sequence truncated to -151 bp also was prepared. When these were introduced into several mammalian cell lines, including C6 glioma, BE(2) neuroblastoma, CV-1 or Ltk- fibroblasts, different basal levels of CAT expression were observed. In the fibroblast lines, THCAT constructs were not expressed unless the cells were treated with forskolin or TPA. However, the low basal expression was not correlated to endogenous expression as THCAT constructs expressed comparably in BE(2)C, HeLa, and C6 glioma. Treatment of any of the cell lines with forskolin, TPA, or a combination of the two agents stimulated the expression by at least two-fold in all cell lines and the maximally induced levels were at least 10-fold over promoterless controls. These data indicate that the essential promoter elements as well as those conferring responsivity to cyclic AMP reside within 151 bp of the transcription start site. However, the array of elements regulating cell-type expression lie, at least in part, beyond the 500-bp region examined. Further, a role for phosphorylation in the regulation of basal and induced transcription of TH is suggested.
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PMID:Effects of second messenger system activation on functional expression of tyrosine hydroxylase fusion gene constructs in neuronal and nonneuronal cells. 168 57

The Ly-6E/A antigen is expressed on activated murine T cells. Using probes made from the previously characterized cDNA, we have isolated a genomic DNA clone encoding the Ly-6A antigen. We determined the DNA sequence of the genomic clone and conducted a functional analysis of the promoter region. Mouse fibroblast BALB/3T3 cells transfected with this genomic clone constitutively expressed Ly-6A antigen on their cell surface. This expression was inducible by alpha/beta and gamma interferons. The Ly-6E 5'-flanking region was analyzed by chloramphenicol acetyltransferase assays in fibroblast cells for cis-acting elements. At least two positive elements were found to be needed for maximum constitutive promoter activity in L cells. One of the positive elements was specifically bound by a CCAAT box-binding protein from crude nuclear extract, as shown by electrophoretic mobility shift assays and footprinting. The other element, which contains a GGAAA motif and has homology to various known enhancers, also showed a specific binding activity. This second positive element when multimerized became a very powerful enhancing element. Interferon treatment could enhance expression of the chloramphenicol acetyltransferase gene fused to the Ly-6E 5'-flanking region in stably transfected BALB/3T3 cells. The elements responsible for this enhancement lie, at least in part, between positions -1760 and -900 of the gene. Surprisingly, there is no sequence homology between this region of Ly-6E and the established consensus for the interferon-stimulated response element, which has been shown functionally important to all previously characterized alpha/beta interferon-inducible promoters. The Ly-6E gene may prove to be a novel system for the study of interferon induction.
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PMID:Characterization of promoter elements of an interferon-inducible Ly-6E/A differentiation antigen, which is expressed on activated T cells and hematopoietic stem cells. 169 28

Fatty acid synthase is regulated by diet and hormones, with regulation being primarily transcriptional. In chick embryo hepatocytes in culture, triiodothyronine stimulates accumulation of enzyme and transcription of the gene. Since the 5'-flanking region of this gene is likely involved in hormonal regulation of its expression, we have isolated and partially characterized an avian fatty acid synthase gene. A genomic DNA library was constructed in a cosmid vector and screened with cDNA clones that contained sequence complementary to the 3' end of goose fatty acid synthase mRNA. A genomic clone (approximately 35 kilobase pairs (kb] was isolated, and a 6.5-kb EcoRI fragment thereof contained DNA complementary to the 3' noncoding region of fatty acid synthase mRNA. Additional cosmid libraries were screened with 5' fragments of previously isolated genomic clones, resulting in the isolation of five overlapping cosmid DNAs. The entire region of cloned DNA spans approximately 105 kb. Exon-containing fragments were identified by hybridization with end-labeled poly(A)+ RNA and by hybridization of labeled exon-containing genomic DNA fragments to fatty acid synthase mRNA. A new set of cDNA clones spanning approximately 3.2 kb was isolated from a lambda-ZAP goose liver cDNA library using the 5'-most exon-containing fragment of the 5'-most genomic DNA clone. This region of mRNA contains a 5'-untranslated sequence and a continuous open reading frame which includes a region that codes for the essential cysteine of the beta-ketoacyl synthase domain. The entire fatty acid synthase gene spans about 50 kb. The 5' 15 kb of the gene contain 7 exons. S1 nuclease and primer extension analyses were used to identify a single site for initiation of transcription, 174 nucleotides upstream from the putative translation initiation codon. Putative "TATA" and "CCAAT" boxes are located 28 and 60 base pairs (bp), respectively, upstream of the site of initiation of transcription. The 5'-flanking 597 bp of DNA contains G/C-rich sequences including several "GC" boxes corresponding to binding sites for the nuclear transcription factor Sp1. Putative sites for AP-2, C/EBP, and the triiodothyronine and glucocorticoid receptors also were found in this region. A chimeric DNA, containing approximately 1.6 kb of 5'-flanking sequence and 139 bp of untranslated sequence of the goose fatty acid synthase gene ligated to the bacterial chloramphenicol acetyl-transferase (CAT) gene, was transfected into chick embryo hepatocytes in culture. Cells treated with triiodothyronine contained increased chloramphenicol acetyltransferase and fatty acid synthase activities.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Isolation and partial characterization of the gene for goose fatty acid synthase. 170 26

To assess the role of cis-acting elements within the smooth muscle alpha-actin gene in smooth muscle cells (SMC), we transfected chicken smooth muscle alpha-actin promoter-chloramphenicol acetyltransferase gene fusion plasmids into SMC derived from rat and chicken aortas. In marked contrast to effects in chicken skeletal myoblasts and fibroblasts, p122CAT (positions -122 to +19), containing two conserved CArG elements, elicited a modest increase in chloramphenicol acetyltransferase reporter activity in chicken SMC. Addition of upstream sequences between -122 and -151 (p151CAT) increased activity in adult chicken SMC. Addition of sequence between positions -151 and -257 (p257CAT) resulted in a 7-fold increase in chloramphenicol acetyltransferase activity over that of p151CAT in rat SMC, but not in chicken SMC. A genomic clone encoding the rat smooth muscle alpha-actin gene was isolated, and the 5'-flanking region was partially characterized. Comparison of primary sequence between rat and chicken promoters showed a conserved E box motif at position -214 in the chicken gene and at position -213 in the rat gene. Results of these studies demonstrate that regions upstream of the conserved CArG elements exert potent regulatory effects on transcription and that SMC require different cis-acting elements than other cell types to transcriptionally regulate this gene.
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PMID:Elements of the smooth muscle alpha-actin promoter required in cis for transcriptional activation in smooth muscle. Evidence for cell type-specific regulation. 173 Jun 87


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