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)

A naturally occurring deletion mutant is observed in plants infected with figwort mosaic virus (FMV), a caulimovirus. The encapsidated mutant genome is formed spontaneously in association with two different strains of FMV in four host plant species. The mutant also appears when cloned wild-type viral DNA is used as the inoculum. The deletion mutant alone is not infectious and it appears unable to replicate after its formation, even in the presence of wild-type virus. The gene for chloramphenicol acetyltransferase was inserted at different positions in the deletion mutant genome, and subsequent transient assays showed that gene expression of the mutant occurs despite the deletion. Sequence analyses of the mutant genome revealed a deletion of 1237-bp segment encompassing a major portion of the coat protein gene and the 5' end of the downstream reverse transcriptase gene. This deletion is associated with consensus signals for RNA splicing including the conserved 5' and 3' splice sites plus surrounding sequences, putative branch point(s) for lariat formation, and an extremely high adenosine content (41%) of the removed fragment. This suggests that splicing of the FMV full-length transcript has occurred prior to reverse transcription and this accounts for the presence and accumulation of encapsidated DNAs with the same deletion.
Virology 1991 Sep
PMID:A naturally occurring deletion mutant of figwort mosaic virus (caulimovirus) is generated by RNA splicing. 187 73

We have cloned and sequenced the 5' untranslated region of the transforming growth factor-beta 3 (TGF-beta 3) mRNA as well as the adjacent genomic sequence. S1 nuclease analysis identified a single transcription start site. We have thus determined that the 5' untranslated region is about 1.1 kb long and contains 11 open reading frames. In vitro translation of the TGF-beta 3 precursor coding sequence was markedly inhibited by the presence of the 5' untranslated region. Similarly, when the 5' untranslated region of TGF-beta 3 was introduced upstream of the coding sequence of chloramphenicol acetyltransferase, in vitro translation was inhibited. Furthermore, upon transfection into 293 cells, chloramphenicol acetyltransferase expression was inhibited by the 5' untranslated region of TGF-beta 3. The degree of translational inhibition was inversely proportional to the amount of transfected DNA. Mutation analysis implicated multiple segments of the 5' untranslated region as contributing to the inhibitory effect. Deletion of much of the 5'-most 640 nucleotides, including 8 of the 11 upstream ATGs, relieved much but not all of the inhibitory influence of the 5' untranslated region of TGF-beta 3 mRNA. The two upstream open reading frames closest to the initiator codon for the TGF-beta 3 coding sequence also decreased translational efficiency, since mutation of either ATG resulted in increased translation. Transfection results with T47-D cells, a cell line which expresses TGF-beta 3 mRNA, were similar to those obtained with the 293 cell line. Thus, TGF-beta 3 mRNA is a recent example of an expanding group of growth-related mRNAs in which the 5' untranslated region contains upstream open reading frames and other sequences which inhibit translation.
Mol Cell Biol 1991 Sep
PMID:Inhibition of translation of transforming growth factor-beta 3 mRNA by its 5' untranslated region. 187 22

The alpha B-crystallin gene is expressed at high levels in lens and at lower levels in some other tissues, notably skeletal and cardiac muscle, kidney, lung, and brain. A promoter fragment of the murine alpha B-crystallin gene extending from positions -661 to +44 and linked to the bacterial chloramphenicol acetyltransferase (CAT) gene showed preferential expression in lens and skeletal muscle in transgenic mice. Transfection experiments revealed that a region between positions -426 and -257 is absolutely required for expression in C2C12 and G8 myotubes, while sequences downstream from position -115 appear to be determinants for lens expression. In association with a heterologous promoter, a -427 to -259 fragment functions as a strong enhancer in C2C12 myotubes and less efficiently in myoblasts and lens. Gel shift and methylation interference studies demonstrated that nuclear proteins from C2C12 myoblasts and myotubes specifically bind to the enhancer.
Mol Cell Biol 1991 Sep
PMID:Expression of the murine alpha B-crystallin gene in lens and skeletal muscle: identification of a muscle-preferred enhancer. 187 25

Lipoproteins from two pathogenic spirochetes (Borrelia burgdorferi and Treponema pallidum) induced the biosynthesis of TNF in murine macrophages and in permanently transformed macrophages of the cell line RAW 264.7. Induction was studied by measuring the secretion of biologically active TNF and by measuring the activity of the reporter enzyme chloramphenicol acetyltransferase (CAT) produced within macrophages transfected with an endotoxin-responsive CAT construct. Several lines of evidence indicated that the induction of TNF and CAT was attributable to the spirochete lipoproteins rather than to contaminating or endogenous LPS: 1) the dose response curves observed for the lipoproteins were markedly different from those obtained with LPS; 2) lipoprotein-mediated activation was unaffected by amounts of polymyxin B that completely neutralized the induction of TNF and CAT by LPS, 3) low concentrations of the lipoproteins induced TNF in macrophages from endotoxin-unresponsive C3H/HeJ mice as effectively as in macrophages from normal C3H/HeN mice, and 4) isolated spirochete lipoproteins, but not a non-lipoprotein immunogen, were potent inducers of CAT in the transformed macrophages. Moreover, LPS was not detected in the B. burgdorferi lipoprotein mixtures by Limulus amebocyte lysate assay. Proteolytic digestion of the intact bacterial protein preparations only modestly diminished their ability to activate the cells, suggesting that small lipopeptides comprise the biologically active portions of the molecules, as is the case with the murein lipoprotein of Escherichia coli. Through their ability to induce TNF production by macrophages, spirochete lipoproteins may play important roles in the development of the local inflammatory changes and the systemic manifestations that characterize syphilis and Lyme disease.
J Immunol 1991 Sep 15
PMID:Lipoproteins of Borrelia burgdorferi and Treponema pallidum activate cachectin/tumor necrosis factor synthesis. Analysis using a CAT reporter construct. 189 Mar 8

Previous work from this laboratory demonstrated that 17-beta estradiol (E2) can directly stimulate the transcription rate of the rat luteinizing hormone beta (LH beta) gene and that an upstream portion of the LH beta gene between -2.0 and -0.6 kilobases could confer an E2-stimulated response to a reporter gene in transient expression assays. To localize the LH beta estrogen response element (ERE) by biological function, portions of the 5'-flanking region of the LH beta gene or synthetic oligonucleotides were inserted in expression vectors next to the herpes simplex virus thymidine kinase promoter fused to the chloramphenicol acetyltransferase gene. Constructs were transfected into GH3 cells, and transfected cells were treated for 48 h with E2. E2 stimulation of activity (2-4-fold) occurred with constructs containing the 15-base pair palindromic sequence (GGACACCATCTGTCC), found at bases -1173 to -1159 relative to the transcriptional start site in the LH beta gene. A construct containing a synthetic oligonucleotide of this putative LH beta ERE was stimulated 1.7-3-fold by E2, while a construct containing two copies of the sequence was stimulated to a slightly higher level (2.5-4.0-fold). An oligonucleotide in which the palindrome was mutated failed to confer E2 stimulation, and mutation of the palindromic region within the upstream region of the LH beta gene also eliminated the E2 response. The anti-estrogen tamoxifen could not elicit a response, nor could dehydrotestosterone or dexamethasone; however, thyroid hormone treatment resulted in a 2-2.5-fold stimulation. The 15-base pair LH beta gene palindrome was found to bind estrogen receptor (ER) complex directly by gel retardation experiments. Labeled LH beta ERE DNA formed three complexes with proteins from immature rat uterine extract. Two of these were associated with ER complexes, as determined by the comigration of [3H] estradiol bound to ER with these complexes, and by the ability of anti-ER antibody to associate with these complexes. The affinity of the LH beta ERE for ER was calculated by Scatchard analysis to be 2.2-5.0 nM, an approximately 5-10-fold lower affinity than for the ERE in the vitellogenin A2 gene region. The mutated ERE, which had no biological activity, could not compete effectively for binding to ER. ER which was heat-transformed at 30 degrees C had a similar affinity (2-5 nM) for the ERE as ER occupied with E2 (2-4 nM), while ER occupied by estrone had a lower affinity (9 nM).(ABSTRACT TRUNCATED AT 400 WORDS)
J Biol Chem 1991 Sep 15
PMID:Identification of an estrogen-responsive element in the rat LH beta gene. DNA-estrogen receptor interactions and functional analysis. 189 4

Act-2 is a cytokine that belongs to a superfamily of structurally related proteins. Act-2 expression is rapidly induced in T cells, B cells, and monocytes upon mitogenic stimulation. The Act-2 genomic locus is on chromosome 17q. The exons and exon/intron splice junctions have been sequenced, as have the sequences upstream of exon 1. A classical TATA box is located immediately upstream of the transcription initiation site. The upstream sequences possess promoter activity and can be functionally activated after treatment of Jurkat T cells with phythohemagglutinin plus phorbol myristrate acetate. In addition, Act-2 promoter chloramphenicol acetyltransferase constructs are expressed in human T cell lymphotropic virus type I (HTLV-I)-infected MT-2 cells and in Jurkat cells which can be induced to express the transactivator gene (tax) product of HTLV-I.
J Biol Chem 1991 Sep 15
PMID:The gene encoding the Act-2 cytokine. Genomic structure, HTLV-I/Tax responsiveness of 5' upstream sequences, and chromosomal localization. 189 35

Plant cutin monomers trigger, and glucose suppresses, the expression of the cutinase gene of pathogenic fungi. To identify the cutinase promoter region responsible for induction by the unique plant components, a promoter analysis was done with transformants. Plasmids were constructed that contained (i) the 5' flanking region of the cutinase gene or its deletion mutants from Fusarium solani pisi fused with a chloramphenicol acetyltransferase (CAT) reporter gene and (ii) a constitutive promoter fused with a hygromycin phosphotransferase gene. Hygromycin-resistant transformants of F. solani pisi generated by electroporation were assayed for CAT activity inducible by cutin hydrolysate and for glucose repression of this induction. CAT was induced in a glucose-repressible manner when fused with a 360-base-pair (bp), or longer, segment of the 5' flanking region of the cutinase gene, and deletion of the next 135 bp abolished this induction. Gel retardation assays showed that a protein(s) in nuclear extract from the fungus bound to the 5' flanking region of cutinase gene, and this binding was also abolished when the same 135-bp segment was deleted. These results show that the -225 to -360 segment of the cutinase gene contains a cis-acting regulatory element that binds trans-acting factor(s) in the nuclei. Treatment of the nuclear extract with immobilized phosphatase abolished binding to the promoter, suggesting that binding required a phosphorylated form of the protein. With isolated nuclei, phosphorylation of a protein occurred only in the presence of both cutin monomer and the fungal protein factor. The presence of protein kinase inhibitor H7 during the preincubation of nuclei with the monomer and protein factor inhibited cutinase gene transcription. These results suggest that cutin monomer causes phosphorylation of a transcription factor that binds to the -225 to -360 segment of the cutinase gene and enhances transcription of this gene.
Proc Natl Acad Sci U S A 1991 Sep 15
PMID:Identification of a fungal cutinase promoter that is inducible by a plant signal via a phosphorylated trans-acting factor. 189 70

We report here for the first time direct injection of genes into fish muscle in vivo. Plasmids used contain either SV40 early promoter, rabbit beta-cardiac myosin heavy chain promoter, human MxA promoter or an artificial promoter, fused to a chloramphenicol acetyltransferase (CAT) or beta-galactosidase reporter gene. CAT assays revealed that most gene constructs were highly expressed. Histochemical analysis showed that beta-galactosidase was strongly expressed at the site of injection within muscle fibres. This method provides an excellent system for testing expression of gene constructs, including those of mammalian origin, in fish muscle in vivo and has the potential for fish vaccination.
FEBS Lett 1991 Sep 23
PMID:Strong expression of foreign genes following direct injection into fish muscle. 191 96

Phorbol esters (TPA) and concanavalin A (ConA) are known to induce granulocyte-macrophage colony-stimulating factor (GM-CSF) production in murine thymoma EL-4 cells by mRNA stabilization. The role of the 3'-untranslated region (3'-UTR) in GM-CSF mRNA stabilization induced by TPA and ConA in EL-4 cells was examined by transfection studies using chloramphenicol acetyltransferase (CAT) constructions. The GM-CSF 3'-UTR contains a 63-nucleotide region at its 3' end with repeating ATTTA motifs which is responsible for mRNA degradation in a variety of cell types (Shaw, G., and Kamen, R. (1986) Cell 46, 659-666). We produced constructs containing most of the GM-CSF 3'-UTR (303 nucleotides, pRSV-CATgm) or the 3'-terminal AT-rich region (116 nucleotides, pRSV-CATau) and measured CAT enzyme activity and CAT mRNA after transient transfection into EL-4 and NIH 3T3 cells. Low levels of CAT activity were seen in both cells with either plasmid compared with levels of CAT activity obtained with pRSV-CAT. TPA treatment caused an approximately 10-fold increase in CAT activity and mRNA in EL-4 cells transfected with pRSV-CATgm. No increases were seen in EL-4 cells transfected with pRSV-CATau or pRSV-CAT. No response to TPA was detected in transfected NIH 3T3 cells, indicating that the response to TPA is relatively cell-specific. There was no increase in CAT activity after ConA treatment in EL-4 or NIH 3T3 cells transfected with any of the constructs suggesting that the GM-CSF 3'-UTR lacks elements that can respond alone to ConA. Nuclear run-on and actinomycin D chase experiments in EL-4 cells showed that TPA induces CAT activity via mRNA stabilization. By linker-substitution mutagenesis we show that TPA inducibility depends on a 60-nucleotide region of the 3'-UTR whose 5' end is located 160 nucleotides upstream of the 5' end of the AU-rich region.
J Biol Chem 1991 Sep 25
PMID:Identification of sequences within the murine granulocyte-macrophage colony-stimulating factor mRNA 3'-untranslated region that mediate mRNA stabilization induced by mitogen treatment of EL-4 thymoma cells. 191 35

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.
J Biol Chem 1991 Sep 25
PMID:Regulatory element analysis and structural characterization of the human sarcomeric mitochondrial creatine kinase gene. 191 43


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>