Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.48 (transcriptase)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cells of the line 3BM-78 derived from murine bone marrow cells infected in vitro with polycythemic Friend leukemia virus (FLV-P) produce virus with spleen focus-forming activity (SFFV) and can be induced to synthesize hemoglobin. Fifteen clones, isolated from this line, have been analyzed in detail for the effect of different inducing agents (dimethyl-sulfoxide, DMSO; hexamethylene bisacetamide, HMBA; and sodium butyrate, SB) on the synthesis of hemoglobin and virus at the clonal level. All the clones proved to be inducible with one or more of the agents, but the degree of the response depended on the type and concentration of the agent used. In general, the effectiveness of the agent--within the usual range of concentration for induction--both for hemoglobin and for virus synthesis, was in the order HMBA greater than DMSO greater than SB. Reverse transcriptase activity was, however, more easily induced than hemoglobin synthesis in that stimulation was seen at lower concentrations of the same inducing agent. This clonal analysis confirmed that virus and hemoglobin production are regulated independently in these erythroleukemic cells chronically infected with FLV-P.
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PMID:Variations in the response of cloned murine friend erythroleukemia cells to different inducers. 616 76

Intermediate subviral particles (ISVP) derived from reovirus represent a simple model system for the switch-on of transcriptase function. In such particles the endogenous transcriptase is present in a switched-off form, one step removed from the switched-on state. Switch-on of transcriptase function is an active process in this system and can be triggered by K+ions. A variety of agents which affect gene expression in cells were tested for an effect on switch-on in ISVP. Marked effects on switch-on in ISVP were observed with a diverse group of test agents, including DMSO and other solvents, BUdR, TdR, caffeine, theophylline, and temperature. The correlation in response between ISVP and cells suggests that the ISVP system may be useful as a model for studying the biochemical mechanisms underlying the perturbative effects of such agents on gene expression in cells.
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PMID:Perturbation of the switch-on of transcriptase activity in intermediate subviral particles from reovirus. 617 50

Exposure of aggregated murine P19 embryonal carcinoma cells to dimethylsulfoxide (DMSO) induces mesoderm and both embryonic cardiac and skeletal muscle differentiation, while retinoic acid (RA) is an inducer of neuroectodermal differentiation. P19 cells constitutively express the retinoic acid receptor alpha (RAR alpha) and RAR gamma mRNAs while RAR beta expression is induced by RA through a consensus RA-response element in the RAR beta promoter. In the present study we show that the RAR beta transcript is strongly expressed in both P19 cells and in a RA-nonresponsive derivative of P19 cells, called RAC65, during DMSO-induced mesoderm and muscle differentiation. Reverse transcriptase-polymerase chain reaction analysis indicated that RAR beta 2 is the predominant isoform expressed in DMSO-differentiated cells, providing the first evidence for RA-independent regulation of RAR beta 2 transcript levels. Immunoblot analysis showed a 3-fold increase in the RAR beta protein expression over basal levels in differentiated cells, and immunohistochemistry indicated that all cells in the culture including muscle reacted positively for the RAR beta protein. RAR beta 2 transcript expression was differentiation-dependent and occurred without transactivation of a transfected RARE beta 2 reporter gene. Little transcription of the RAR beta gene was detected in nuclear run-off assays of undifferentiated P19 cells and only a small increase in transcription was observed in nuclei from DMSO-treated cells. RA treatment of P19 cells stably transfected with the RA-responsive element from the RAR beta gene showed that RAR beta 2 mRNA expression during DMSO differentiation was associated with increased sensitivity to RA. Together these data show that RAR beta 2 is expressed spontaneously in an apparently RA-independent manner in differentiating mesoderm and mesoderm derivatives, resulting in increased sensitivity to RA in these cells.
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PMID:Spontaneous retinoic acid receptor beta 2 expression during mesoderm differentiation of P19 murine embryonal carcinoma cells. 1092 6

Expression of human beta-defensins is correlated with differentiation in the oral epithelium, consistent with their function as part of the epithelial antimicrobial barrier. Because calcium is a known regulator of epithelial differentiation, we tested the hypothesis that calcium concentration mediates beta-defensin expression. Gingival epithelial cells were cultured in medium containing low calcium concentration (0.03 mM), then either changed to high extracellular calcium concentrations or stimulated with thapsigargin to release intracellular calcium stores in the presence or absence of BAPTA-AM, a calcium chelator. Human beta-defensin-2 (hBD-2) mRNA expression was rapidly induced by thapsigargin, and more slowly induced by high extracellular calcium. Induction of hBD-2 peptide was confirmed by immunofluorescence. BAPTA-AM inhibited hBD-2 induction by both thapsigargin and calcium in a dose-dependent fashion. In addition, BAPTA-AM inhibited hBD-2 induction by a bacterial stimulant. Collectively, these findings demonstrate that intracellular calcium is a critical mediator of hBD-2 expression. Abbreviations used in this study are: BAPTA-AM, 1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetra-acetic acid tetrakis (acetoxymethyl ester); DMSO, dimethylsulfoxide; F. nucleatum, Fusobacterium nucleatum; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; HBDs, human beta-defensins; HGECs, human gingival epithelial cells; MAP, mitogen-activated protein; and RT-PCR, reverse-transcriptase/polymerase chain-reaction.
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PMID:Intracellular calcium in signaling human beta-defensin-2 expression in oral epithelial cells. 1457 98

An arsenite biosensor plasmid was constructed in Escherichia coli by inserting the operator/promoter region of the ars operon and the arsR gene from E. coli and the crtA gene, which is responsible for carotenoid synthesis in the photosynthetic bacterium, Rhodovulum sulfidophilum, into the broad-host-range plasmid vector, pRK415. The biosensor plasmid, pSENSE-As, was introduced into a crtA-deleted mutant strain of R. sulfidophilum (CDM2), which is yellow in culture due to its content of spheroiden (SE) and demethylspheroidene (DMSE). CDM2 containing pSENSE-As changed from yellow to red by the addition of arsenite, which caused enzymatic transformation of SE and DMSE to spheroidenone (SO) and demethylspheroidenone (DMSO). Reverse transcriptase PCR analysis showed that the color change depended on transcription of the crtA gene in pSENSE-As. The color change could be clearly recognized with the naked eye at 5 microg/l arsenite. The biosensor strain did not respond to other metals except for bismuth and antimony, which caused significant accumulation of SO and DMSO in the cells at 60 and 600 microg/l, respectively. This biosensor indicates the presence of arsenite with a bacterial color change without the need to add a special reagent or substrate for color development, enabling this pollutant to be monitored in samples by the naked eye in sunlight, even where electricity is not available.
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PMID:Whole-cell arsenite biosensor using photosynthetic bacterium Rhodovulum sulfidophilum. Rhodovulum sulfidophilum as an arsenite biosensor. 1673 29

Charcot-Leyden crystal protein (CLC) is a major secretory effector protein of eosinophils. In addition, CLC has been identified as marker for regulatory T-cells and differential expression of CLC has been described under diverse pathological conditions. By analysis of DNA microarray data from peripheral blood mononuclear cells (PBMC) we found differences for the expression of CLC between PBMC that had been cryopreserved or had been used for RNA isolation immediately after cell separation. Reverse transcriptase-polymerase chain reaction (RT-PCR) of separated cell populations indicated that contaminating granulocytes were the main source of CLC transcripts in PBMC. CLC was only detectable in fresh PBMC and not in cryopreserved material. Transcripts corresponding to CLC were also detectable by RT-PCR only in fresh PBMC and eosinophils. Loss of CLC transcripts in PBMC was induced by a short pulse with dimethyl sulfoxide (DMSO), indicating that the freezing medium was responsible for this phenomenon. We conclude that CLC transcripts are lost during cryopreservation in the presence of DMSO and can never be identified as differentially expressed in cryopreserved samples.
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PMID:Loss of detectability of Charcot-Leyden crystal protein transcripts in blood cells after treatment with dimethyl sulfoxide. 1878 35

The mammalian reovirus (MRV) genome comprises 10 double-stranded RNA (dsRNA) segments, packaged along with transcriptase complexes inside each core particle. Effects of four small molecules on transcription by MRV cores were studied for this report, chosen for their known capacities to alter RNA duplex stability. Spermidine and spermine, which enhance duplex stability, inhibited transcription, whereas dimethyl sulfoxide and trimethylglycine, which attenuate duplex stability, stimulated transcription. Different mechanisms were identified for inhibition or activation by these molecules. With spermidine, one round of transcription occurred normally, but subsequent rounds were inhibited. Thus, inhibition occurred at the transition between the end of elongation in one round and initiation in the next round of transcription. Dimethyl sulfoxide or trimethylglycine, on the other hand, had no effect on transcription by a constitutively active fraction of cores in each preparation but activated transcription in another fraction that was otherwise silent for the production of elongated transcripts. Activation of this other fraction occurred at the transition between transcript initiation and elongation, i.e., at promoter escape. These results suggest that the relative stability of RNA duplexes is most important for certain steps in the particle-associated transcription cycles of dsRNA viruses and that small molecules are useful tools for probing these and probably other steps.
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PMID:Probing the transcription mechanisms of reovirus cores with molecules that alter RNA duplex stability. 1929 68