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:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

When 15-deoxyspergualin (DSG) was administered into [BALB/c-->C3H/He] bone marrow (BM) chimeras from day 14 to day 25, increased platelet counts were observed from day 25 to day 33. Twofold increase of platelet counts was observed in DSG-treated BM chimeras compared with phosphate buffered saline (PBS)-treated BM chimeras. By using reverse transcriptase-polymerase chain reaction (RT-PCR), several cytokine mRNA expressions were analyzed in order to clarify which cytokines are involved in thrombopoiesis. So far, interleukin-6 (IL-6), leukemia inhibitory factor (LIF), stem cell factor (SCF), and IL-11 have been reported to have potent thrombopoietic activity in vivo. Although some other cytokines such as IL-3 and granulocyte-macrophage colony-stimulating factor (GM-CSF) possess the capacity of thrombopoiesis, megakaryocytopoiesis is more marked in these cytokines. IL-6 mRNA expression was increased in spleen cells from DSG-treated BM chimeras from day 25 to day 32 and in bone marrow cells from day 19 to day 28. LIF mRNA expression was not significantly increased compared with PBS control. Although SCF mRNA expression was increased, the kinetics of increased SCF mRNA expression did not fit the kinetics of increased platelet counts. Increased mRNA expression in other hematopoietic cytokines, such as IL-3, granulocyte-colony stimulating factor (G-CSF) and GM-CSF were also observed, thus suggesting that these cytokines may synergistically support thrombopoiesis in concert with IL-6. These results suggest that IL-6 and other hematopoietic cytokines might induce increased platelet counts, although the involvement of thrombopoietin (TPO) and IL-11 should be analyzed in the future.
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PMID:A novel immunosuppressant 15-deoxyspergualin and thrombopoiesis. 795 88

We and others have described methods to label specific nucleic acid sequences in fixed cells by reverse in situ transcription (IST). They are simple alternatives to the tedious steps of in situ hybridization with labeled probes. We have favored use of thermostable DNA polymerases after heat denaturation of template secondary structure, accompanied by synthesis of cDNA from an annealed primer, but the approach has been limited by the low reverse transcriptase (RT) activity of Taq polymerase and delayed detection methods. We have improved the technique by the use of recombinant Thermus thermophilus (rTth) DNA polymerase and fluorescein-12-dUTP (FIST). Jurkat T lymphocytes were stimulated with ionomycin + phorbol myristate acetate to produce interleukin-2 (IL-2) mRNA in vitro overnight. They were cytospun onto slides and fixed in 70% ethanol + 30% DEPC-treated water, acetone, and air-dried. The slides were placed on a temperature-controlled heating block, and the cell spot was covered with a plastic coverslip. The temperature was raised to 95 degrees C, and 5-10 microliters of modified Perkin-Elmer/Cetus rTth RT reaction mix was injected under the edge of the coverslip. Each 10 microliters of mix in DEPC-water contained 10 mM Tris-HCl, pH 8.3, 90 mM KCl, 1 mM MnCl2, 1 mM dithiothreitol, 10 U placental ribonuclease inhibitor, 0.125 mM dA,C,GTPs, 0.1 mM fluorescein-12-dUTP, 2 U rTth DNA polymerase, and 4 pM 22-mer oligonucleotide primer, which spanned the second intron of IL-2. After 3 min at 95 degrees C, 1 min at 50 degrees C and 10 min at 72 degrees C, the slides were washed in 0.5 x phosphate-buffered saline, pH 7.0, at 42 degrees C, in 70% ethanol, 100% ethanol, and air-dried. The cells were mounted in antifade solution (2% n-propyl gallate in 70% glycerol), and could be viewed immediately by fluorescence microscopy. Image analysis showed that stimulated Jurkat cells were brighter than uninduced controls or those treated with RNase or without polymerase or primer. FIST appears to be useful for the detection of specific mRNAs in single cells.
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PMID:In situ transcription with Tth DNA polymerase and fluorescent nucleotides. 798 81

The alpha T3-1 cell line, an immortalized gonadotroph cell line, expresses high levels of the gonadotrophin-releasing hormone (GnRH) receptor. Sustained exposure of these cells to the GnRH receptor agonist des-Gly10-[D-Ala6]luteinizing hormone-releasing hormone ethylamide resulted in a substantial down-regulation of cellular levels of a combination of the alpha subunits of the phospholipase C-beta 1-linked G proteins Gq and G11, as assessed by immunoblotting with an antiserum able to identify these two proteins equally. This effect was dependent upon the concentration of agonist used (EC50 = 4 nM) and on the time of the treatment (t1/2 = 6 hr) when a maximally effective concentration of agonist (1 microM) was used. Comparison of agonist regulation of inositol phosphate generation and Gq alpha/G11 alpha down-regulation demonstrated that effects on inositol phosphate production were approximately 3-fold more potent. In contrast to Gq alpha/G11 alpha, membrane-associated levels of Gs alpha and G12 alpha, the G proteins that transduce stimulatory and inhibitory regulation, respectively, of adenylyl cyclase, were not altered by agonist treatment. Analysis of mRNA by reverse transcriptase/polymerase chain reaction indicated the coexpression by alpha T3-1 cells of mRNA corresponding to both Gq alpha and G11 alpha. Immunoblotting with antisera selective for either Gq alpha or G11 alpha confirmed their coexpression. Resolution of membranes from untreated and agonist-treated alpha T3-1 cells under sodium dodecyl sulfate-polyacrylamide gel electrophoresis conditions able to separate Gq alpha from G11 alpha indicated that G11 alpha was more prevalent than Gq alpha at steady state but that agonist treatment regulated cellular levels of both of these G proteins in a nonselective manner. Sustained activation of protein kinase C with phorbol myristate acetate was unable to mimic agonist regulation of cellular Gq alpha/G11 alpha levels, as was treatment of alpha T3-1 cells with the selective protein kinase C inhibitor chelerythrine. These data suggest that the GnRH receptor is able to interact functionally with both Gq alpha and G11 alpha in alpha T3-1 cells and that sustained exposure to a GnRH receptor agonist selectively regulates the cellular levels of the G proteins that interact with the receptor.
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PMID:The gonadotrophin-releasing hormone receptor of alpha T3-1 pituitary cells regulates cellular levels of both of the phosphoinositidase C-linked G proteins, Gq alpha and G11 alpha, equally. 805 44

The ability of thermostable DNA polymerases to mediate template-dependent DNA synthesis in the presence of phenol has been examined as monitored by amplification of a specific Borrelia burgdorferi rRNA sequence. Tth DNA polymerase displayed the unique property of maintaining both DNA- and RNA-dependent DNA polymerase activities in the presence of 2%-5% (vol/vol) of phenol-saturated PBS buffer. Tth DNA polymerase mediated reverse transcriptase activity was unaffected by phenol-saturated phosphate-buffered saline concentrations as high as 15% (vol/vol). By contrast, Taq DNA Polymerase was inactive under these conditions. The ability to function in the presence of phenol can greatly simplify reverse transcriptase, PCR and reverse transcription-PCR protocols since the phenol-saturated aqueous phase of a phenol partition can be added directly to the reaction mixtures. The simplicity of the procedures described should have applicability to a broad range of basic research, clinical and forensic applications.
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PMID:A distinctive property of Tth DNA polymerase: enzymatic amplification in the presence of phenol. 813 48

Previous studies on electrochemical reduction of the HIV reverse transcriptase inhibitor, 3'-azido-3'-deoxythymidine (Zidovudine, AZT) and several of its analogues, have been extended to 2'-AZdT and two of the intracellular metabolites of AZT, the 5'-O-glucuronide (GAZT) and the 5'-phosphate (AZTMP). Also investigated were azido nucleosides with aglycons susceptible to electrochemical reduction, cytosine and adenine. The surface activities of these compounds at the mercury electrode were examined. In all instances, reduction of the azido group was a two-electron process, with conversion to an amino group. For an azido adenine nucleoside, it proved possible to reduce the azido group without affecting the aglycon. Electrochemical reduction is shown to provide a simple one-step synthesis of amino nucleosides from the available azido nucleosides. The reduced compounds, several hitherto unknown, are useful reference standards for following intracellular metabolism of azido nucleosides, and may also prove of interest as new potential antimetabolites.
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PMID:Electrochemical reduction products of azido nucleosides, including zidovudine (AZT): mechanisms and relevance to their intracellular metabolism. 821 58

Interleukin (IL)-8 is a member of the supergene family of proinflammatory and chemotactic cytokines recently termed chemokines. IL-8 has been implicated in the pathogenesis of inflammatory skin diseases such as psoriasis. In this study, IL-8 mRNA expression and protein production were determined in normal cultured human epidermal keratinocytes after ultraviolet-B (UVB) irradiation. Messenger RNA levels were determined by the reverse transcriptase-polymerase chain reaction (RT-PCR) method. Total RNA was extracted from cultured keratinocytes at various time points post-irradiation, reverse transcribed to cDNA, and amplified by PCR using a labeled specific primer for the target gene. Amplified products were sized by electrophoresis, visualized by autoradiography, and quantitated by densitometry. Autoradiographs were normalized relative to glyceraldehyde-3-phosphate-dehydrogenase (G3PDH) signals. Constitutive expression of IL-8 mRNA was seen in normal cultured keratinocytes. After 100 or 300 J/m2 UVB irradiation, a rapid increase in IL-8 mRNA level was observed within 1 h after irradiation. At 24 h after irradiation, the mRNA level was elevated 11-13 times compared with the control level. Production of IL-8 protein in culture supernatants was assayed by enzyme-linked immunosorbent assay (ELISA). Significant levels of IL-8 protein were observed at 24 h after irradiation. Cycloheximide treatment blocked this IL-8 protein induction. As IL-8 is known to be an inflammatory cell chemotactic factor, these results suggest a possible role for IL-8 in UVB-induced skin inflammation and diseases.
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PMID:IL-8 gene expression and production in human keratinocytes and their modulation by UVB. 822 30

Genes, constituted by the deoxyribonucleic acid (DNA) contain all the genetic information of a cell. DNA is a double helix consisting of two antiparallel polynucleotide chains where each nucleotide is composed of the association between a base, a sugar and a phosphate group. The chains are associated by hydrogen bonds between the bases. Guanine bonds specifically with cytosine while adenine bonds specifically with thymine. The sequence of DNA is related to the sequence of protein by the genetic code. Each aminoacid is represented by a codon that consists of a nucleotide triplet. Information is expressed by a two-step process. The first step, transcription generates a single-stranded ribonucleic acid called messenger RNA (mRNA) (where a uracil base is present instead of a thymine) which acts as an intermediate molecule. In this step, RNA splicing is one of the maturation processes consisting of joining the exons by removing the introns of the precursor RNA molecule. The second step, translation, converts the nucleotide sequence into the sequence of aminoacids. Since the 1970s, the progress in DNA technology consisting of the development of molecular cloning, DNA library construction and sequencing methods, has made it possible to isolate and analyze specific genes directly from the genome. A sequence of genomic or complementary DNA (cDNA) is cloned by inserting it into a vector (plasmid or phage) that can replicate independently in bacteria. Before cloning, genomic DNA is digested into fragments by restriction enzymes (endonucleases cleaving specific sequences within double-stranded DNA) whereas RNA sequences are copied into cDNA by reverse transcriptase.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Fundamental aspects of molecular biology. The multigene family of 5-HT1 receptors]. 827 6

Several 5-monophosphate D4T derivatives and their analogues were synthesized as potential lipophilic prodrugs of D4T. Cholesteryl D4T phosphate diester and bis-5'-D4T phosphate inhibited HIV replication in CEM-Cl13 cells more efficiently than D4T itself as measured by the inhibition of cytopathic effect based on MTT assay or reverse transcriptase activity. The two compounds were devoid of toxicity on CEM-Cl13 cells at doses equal to 50 and 100 microM, respectively, which brought the selectivity index into the same range as AZT.
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PMID:Synthesis and anti-HIV evaluation of D4T and D4T 5'-monophosphate prodrugs. 838 24

The ability of highly purified preparations of poliovirus RNA-dependent RNA polymerase, 3Dpol, to unwind RNA duplex structures was examined during a chain elongation reaction in vitro. Using an antisense RNA prehybridized to an RNA template, we show that poliovirus polymerase can elongate through a highly stable RNA duplex of over 1,000 bp. Radiolabeled antisense RNA was displaced from the template during the reaction, and product RNAs which were equal in length to the template strand were synthesized. Unwinding did not occur in the absence of chain elongation and did not require hydrolysis of the gamma-phosphate of ATP. The rate of elongation through the duplex region was comparable to the rate of elongation on the single-stranded region of the template. Parallel experiments conducted with avian myeloblastosis virus reverse transcriptase showed that this enzyme was not able to unwind the RNA duplex, suggesting that strand displacement by poliovirus 3Dpol is not a property shared by all polymerases.
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PMID:RNA duplex unwinding activity of poliovirus RNA-dependent RNA polymerase 3Dpol. 838 85

The preservation of viable infectious agents for future studies could create complicated logistic problems, and at times it is not feasible. Methods for preserving the genetic integrity of inactivated agents would not only facilitate these studies but would also make it possible to transport inactivated preparations around the world. In this report, the effect of inactivation on the genetic material of infectious bursal disease virus (IBDV) was studied. Tissues from the bursa of Fabricius of birds experimentally infected 3 days earlier with the classic STC strain of IBDV were collected and immediately placed in a solution of phenol:chloroform:isoamyl alcohol (25:24:1) for 24, 48, 72, or 96 hr. Infected bursal tissue not treated with the phenol:chloroform solution and uninfected phenol: chloroform bursal tissue were used as controls. In a separate experiment, bursal tissues collected 5 days following infection of specific-pathogen-free birds with the classic STC or variant 1084-E strain were placed in the phenol:chloroform solution for 2 wk. All bursal samples were tested for viable IBDV following phenol:chloroform treatment. The tissues were washed in phosphate-buffered saline to remove phenol and then homogenized. Viability of the viruses in homogenized bursal tissue was examined by inoculation of embryonated chicken eggs. Viable IBDV was not observed in any phenol:chloroform-treated bursal tissue but was observed in the infected but non-phenol:chloroform-treated control bursa. The reverse transcriptase/polymerase chain reaction (RT/PCR) was used to test the integrity of the viral RNA. Viral RNA from the nontreated control and all infected bursal samples treated with phenol:chloroform solution at all the time points examined were transcribed into DNA, and a 394-bp fragment of the VP2 gene was amplified using specific primers in the PCR. The RT/PCR assay was negative using the phenol:chloroform-treated uninfected bursal tissue. This study clearly demonstrated that phenol:chloroform treatment of infected bursal tissue inactivated the classic and variant IBDV strains tested and preserved the viral RNA for use in the RT/PCR assay.
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PMID:Infectious bursal disease viral RNA amplification using RT/PCR from bursa tissue following phenol: chloroform inactivation of the virus. 879 Aug 99


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