Search results for "Chloramphenicol O-Acetyltransferase"

showing 5 items of 5 documents

p53 is involved in regulation of the DNA repair gene O6-methylguanine-DNA methyltransferase (MGMT) by DNA damaging agents

1998

The DNA repair protein O6-methylguanine-DNA methyltransferase (MGMT) is inducible by genotoxic stress. MGMT induction results from transcriptional activation of the MGMT gene which is a specific response to DNA damage. A possible factor involved in triggering MGMT induction might be p53, because both p53 and MGMT are activated by DNA breaks. To study the effect of p53 on induction of the MGMT gene, we compared the presence of functional wild-type (wt) and mutant p53 with MGMT expression level in various mouse fibroblasts and rat hepatoma cell lines upon genotoxic treatment. Cells which responded to ionizing radiation (IR) by MGMT induction displayed functional p53, whereas in cells not expr…

Chloramphenicol O-AcetyltransferaseCancer ResearchMethyltransferaseDNA RepairDNA damageDNA repairRecombinant Fusion ProteinsBiologyTransfectionDNA methyltransferaseDNA AntisenseGene Expression Regulation EnzymologicMiceO(6)-Methylguanine-DNA MethyltransferaseLiver Neoplasms ExperimentalGene expressionDNA Repair ProteinTumor Cells CulturedGeneticsAnimalsCancer epigeneticsPromoter Regions GeneticneoplasmsMolecular BiologyCell NucleusMice KnockoutCell Cycle3T3 CellsTransfectionGenes p53Molecular biologydigestive system diseasesRatsCancer researchTumor Suppressor Protein p53DNA DamageOncogene
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Binding of Tat Protein to TAR Region of Human Immunodeficiency Virus Type 1 Blocks TAR-Mediated Activation of (2′-5′)Oligoadenylate Synthetase

1990

The TAR sequence of the 5' leader of HIV-1 long terminal repeat-directed mRNA was found to be able to bind to and to activate double-stranded RNA-dependent (2'-5')A synthetase. Binding of TAR to the purified synthetase in vitro was abolished by addition of HIV-1 Tat protein, which binds to this sequence with a high affinity. Inhibition of TAR-mediated activation of (2'-5')A synthetase by Tat was prevented in the presence of the Zn2+ and Cd2+ chelators o-phenanthroline and penicillamine, which did not impair TAR-synthetase interaction. Transient expression assays of bacterial chloramphenicol acetyltransferase (CAT) gene in HeLa cells revealed that the levels of both CAT mRNA and CAT protein …

Chloramphenicol O-AcetyltransferaseGene Expression Regulation ViralImmunologyBiologyTransfectionChloramphenicol acetyltransferaseTar (tobacco residue)InterferonVirology2'5'-Oligoadenylate SynthetasemedicineHumansRNA MessengerGeneRepetitive Sequences Nucleic AcidRegulation of gene expressionMessenger RNA2'-5'-OligoadenylatePenicillamineTransfectionMolecular biologyEnzyme ActivationZincInfectious DiseasesGenes tatHIV-1Trans-ActivatorsInterferonsCadmiumPhenanthrolinesmedicine.drugAIDS Research and Human Retroviruses
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Stress response in mesoangioblast stem cells

2006

Stem cells are presumed to survive various stresses, since they are recruited to areas of tissue damage and regeneration, where inflammatory cytokines and cytotoxic cells may result in severe cell injury. We explored the ability of mesoangioblasts to respond to different cell stresses such as heat, heavy metals and osmotic stress, by analyzing heat shock protein (HSP)70 synthesis as a stress indicator. We found that the A6 mesoangioblast stem cells constitutively synthesize HSP70 in a heat shock transcription factor (HSF)-independent way. However, A6 respond to heat shock and cadmium treatment by synthesizing HSP70 over the constitutive expression and this synthesis is HSF1 dependent. The e…

Chloramphenicol O-AcetyltransferaseHot TemperatureOsmotic shockRecombinant Fusion ProteinsBlotting WesternHypertonic SolutionsElectrophoretic Mobility Shift AssayBiologyResponse ElementsTransfectionMesodermMiceSTRESS RESPONSE STEM CELLS MOUSE MESOANGIOBLASTS.Heat Shock Transcription FactorsHeat shock proteinMetals HeavyAnimalsRNA MessengerHSF1Promoter Regions GeneticMolecular BiologyCells CulturedMesoangioblastHSC70 Heat-Shock ProteinsCell BiologyTransfectionHematopoietic Stem CellsMolecular biologyCell biologyHsp70Heat shock factorDNA-Binding ProteinsGene Expression RegulationStem cellTranscription Factors
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Enhancer blocking activity located near the 3′ end of the sea urchin early H2A histone gene

1997

The sea urchin early histone repeating unit contains one copy of each of the five histone genes whose coordinate expression during development is regulated by gene-specific elements. To learn how within the histone repeating unit a gene-specific activator can be prevented to communicate with the heterologous promoters, we searched for domain boundaries by using the enhancer blocking assay. We focused on the region near the 3′ end of the H2A gene where stage-specific nuclease cleavage sites appear upon silencing of the early histone genes. We demonstrated that a DNA fragment of 265 bp in length, defined as sns (for silencing nucleoprotein structure), blocked the enhancer activity of the H2A…

Chloramphenicol O-AcetyltransferaseMaleSea urchinEmbryo Nonmammaliananimal structuresRecombinant Fusion ProteinsMolecular Sequence DataEnhancer RNAsSettore BIO/11 - Biologia MolecolareHistonesChloramphenicol acetyltransferaseAnimalsHumansEnhancer trapCoding regionAmino Acid SequencePromoter Regions GeneticEnhancerOvumRepetitive Sequences Nucleic AcidCell NucleusBase CompositionMultidisciplinaryBase SequencebiologyActivator (genetics)Histone genesPromoterGastrulaBiological SciencesSpermatozoaMolecular biologyEnhancer Elements GeneticNucleoproteinsHistoneSea UrchinsSettore BIO/03 - Botanica Ambientale E Applicatabiology.proteinFemaleEnhancer blocking activityHeLa Cells
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Down-regulation of early sea urchin histone H2A gene relies on cis regulative sequences located in the 5' and 3' regions and including the enhancer b…

2004

The tandem repeated sea urchin alpha-histone genes are developmentally regulated by gene-specific promoter elements. Coordinate transcription of the five genes begins after meiotic maturation of the oocyte, continues through cleavage, and reaches its maximum at morula stage, after which these genes are shut off and maintained in a silenced state for the life cycle of the animal. Although cis regulative sequences affecting the timing and the level of expression of these genes have been characterized, much less is known about the mechanism of their repression. Here we report the results of a functional analysis that allowed the identification of the sequence elements needed for the silencing …

Chloramphenicol O-Acetyltransferaseanimal structuresEmbryo NonmammalianMicroinjectionsgenomic insulatorDown-RegulationSettore BIO/11 - Biologia MolecolareBiologyRegulatory Sequences Nucleic AcidDNA-binding proteinHistonesStructural BiologyTranscription (biology)Gene expressionHistone H2Atranscriptional repressionGene silencingAnimalsGene SilencingTransgenesEnhancerPromoter Regions GeneticMolecular BiologyGenePsychological repressionhistone geneRepetitive Sequences Nucleic AcidSequence DeletionGeneticsenhancer blockerGastrulaEnhancer Elements GeneticSea Urchinsembryonic structuresProtein BindingJournal of molecular biology
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