Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.7 (DNA polymerase)
 17,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cultured synovial cells from 8 patients with rheumatoid arthritis (RA) and 7 subjects without joint disease were assayed and comapred for RNA-directed and DNA-directed DNA polymerase activity. No activity was found in either RA or control specimens using a synthetic RNA template that specificically detects oncornavirus RNA-directed DNA polymerase. The DNA-directed DNA polymerase activity of RA specimens was increased (P less than 0.10) in the high-speed pellet fraction of cell lysates. The possible relationship of these finding to virus infection in RA is disscussed.
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PMID:DNA polymerase activity of cultured rheumatoid synovial cells. 16 46

A DNA polymerising complex directed by endogenous DNA has been partially purified from 11-day-old embryonic chick brain microsomes by DEAE-cellulose and phosphocellulose column chromatography. The active fractions are eluted together with an exogenous DNA-directed DNA polymerase; after Sephadex gel filtration, the endogenous activity remains associated with a high molecular weight DNA-directed DNA polymerase. The endogenous activity of the complex has been shown to be RNase-resistant and actinomycin-sensitive. It requires potassium, an ATP-regenerating system and all four deoxyribonucleoside triphosphates for full activity. The significance of this activity with regard to the protovirus hypothesis is discussed.
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PMID:Endogenous DNA-directed DNA synthesising system in a microsomal fraction of embryonic chick brain. 86 84

The influence of 9-beta-D-arabinofuranosyladenine (ara-A) and its 5'-triphosphate derivative on programmed synthesis was tested with an intact cell system as well as with isolated enzyme systems. The effect of ara-A was tested in mouse lymphoma cells (L5178Y). The compound reduces cell proliferation in low concentration by cytostasis; under high ara-A concentration of radioactive precursors into DNA, RNA, and protein showed that ara-A selectively inhibits DNA synthesis. Formation of a polysome complex is not affected by ara-A. [3H]ara-A is incorporated into DNA in an intact cell system; 1 molecule of ara-A is incorporated per 8000 molecules of deoxyadenosine. Most of the ara-A molecules appeared to be in internucleotide linkages. Incorporation of ara-A into RNA could not be detected. 9-BETA-D-Arabinofuranosyladenine 5'-triphosphate (ara-ATP) does not reduce the incorporation rate of the following enzymes, isolated from quail oviducts: DNA-dependent RNA polymerases I and II, polyadenylic acid polymerase, and poly(adenosine diphosphate ribose) polymerase. The compound was found to inhibit DNA synthesis catalyzed by DNA polymerases isolated from quail oviducts and from oncogenic RNA viruses (Rous sarcoma viruses). All the enzymes tested were inhibited by ara-ATP in a competitive way with respect to deoxyadenosine 5'-triphosphate. The highest affinity of ara-ATP, i.e., the highest inhibitory potency of the drug, was found in the assays with the eukaryotic low-molecular DNA-dependent DNA polymerase. The influence on the eukaryotic high-molecular DNA-dependent Dna polymerase was a litte less. Compared to the eukaryotic DNA polymerases, the viral enzymes (RNA-directed DNA polymerase and DNA-directed DNA polymerase) are affected to a smaller extent by ara-ATP. No effects of ara-A and ara-ATP are observed in a protein-synthesizing, cell-free system isolated from L5178Y cells.
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PMID:Mode of action of 9-beta-D-arabinofuranosyladenine on the synthesis of DNA, RNA, and protein in vivo and in vitro. 114 31

RNAase-sensitive DNA polymerase activity was demonstrated in synovial membrane preparations from 23 out of 25 rheumatoid arthritis patients. Control groups consisted of twelve patients with osteoarthrosis, four with secondary osteoarthrosis, and twelve with other conditions. The last group showed no activity, while the results with the other two groups were varied. The properties of the polymerase enzyme, such as its stimulation by synthetic templates and inhibition by actinomycin D, were not consistent with it being associated with an oncogenic virus; it seems to be more like that found in stimulated normal human lymphocytes, described as an RNA-primed DNA-directed DNA polymerase.
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PMID:DNA polymerase activity in rheumatoid synovial membranes. 115 79

A DNA-directed DNA polymerase has been isolated from murine liver mitochondria. The mitochondrial DNA polymerase is distinguishable from other DNA polymerases found in the nucleus and cytosol of murine cells by several enzymatic and physical properties. It is stimulated 5--6-fold by 0.15 M KCl, does not require a sulfhydryl reducing agent for activity, and is inhibited by ethidium bromide or ATP. The enzyme has a sedimentation coefficient of 8.8 S in the presence of up to 0.5 M KCl, a molecular weight of 150--170000, and utilizes natural templates in the following order of preference: activated DNA (100%), single stranded DNA (24%), and native DNA (5%).
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PMID:A DNA-directed DNA polymerase from murine liver mitochondria. 119 2

A sequence of 3299 nt, contiguous with the previously sequenced quinate permease-encoding (qutD) gene and encompassing the dehydroshikimate dehydratase-encoding (qutC) gene, has been determined. Northern-blot analysis detected (i) a quinate-inducible mRNA of the expected size for the qutC gene, and (ii) a quinate-inducible mRNA of 1.45 kb divergently transcribed away from qutC towards qutD. Computer-aided sequence analysis identified an ORF of 1047 nt corresponding to the qutC gene encoding dehydroshikimate dehydratase. In addition, a genetically uncharacterized 1188-nt gene, designated qutH and containing a putative intron of 61 nt, was identified between qutC and qutD. The inferred protein sequence encoded by qutH contains a putative 'zinc cluster' motif and has a low (16%) but significant similarity with the DNA-directed DNA polymerase of hepatitis B virus. The results are interpreted as being consistent with the view that the qutH gene encodes a DNA-binding protein, possibly involved in the regulation of genes essential for the utilisation of protocatechuic acid.
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PMID:A second gene (qutH) within the Aspergillus nidulans-quinic-acid utilisation gene cluster encodes a protein with a putative zinc-cluster motif. 133 61

The mobile element jockey is similar in structural organization and coding potential to the LINEs of various organisms. Current models of the mechanism of transposition involve reverse transcription of an RNA intermediate and utilization of element-encoded proteins. As it is demonstrated here, a 2.23 kb DNA fragment from the region of the jockey encoding the putative reverse transcriptase, was stably introduced into the expression system under inducible control of the Escherichia coli lac regulatory elements. We describe the expression of the 92 kDa protein and identify this polypeptide alone as authentic jockey reverse transcriptase based on some of its physical and enzymic properties. The jockey polymerase demonstrates RNA-directed and DNA-directed DNA polymerase activities, but lacks detectable RNase H, has a temperature optimum at 26 degrees C, requires Mg2+ or Mn2+ as a cofactor and is inactivated by sulfhydryl reagent. The enzyme prefers poly(rC) and poly(rA) as template and "activated" DNA is not effective. The results of this work suggest that the RNA-directed DNA polymerase coded by jockey elements may be involved in the transcription of the elements.
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PMID:[Cloning and expression in Escherichia coli of reverse transcriptase coded by the mobile genetic element jockey]. 138 Jun 45

The mobile element jockey is similar in structural organization and coding potential to the LINEs of various organisms. It is transcribed at different stages of Drosophila ontogenesis. The Drosophila LINE family includes active transposable elements. Current models for the mechanism of transposition involve reverse transcription of an RNA intermediate and utilization of element-encoded proteins. As demonstrated here, a 2.23 kb DNA fragment from the region of jockey encoding the putative reverse transcriptase was stably introduced into an expression system under inducible control of the Escherichia coli lac regulatory elements. We describe the expression of the 92 kDa protein and identify this polypeptide alone as the authentic jockey reverse transcriptase based on some of its physical and enzymic properties. The jockey polymerase demonstrates RNA and DNA-directed DNA polymerase activities but lacks detectable RNase H, has a temperature optimum at 26 degrees C, requires Mg2+ or Mn2+ as a cofactor and is inactivated by sulphydryl reagent. The enzyme prefers poly(rC) and poly(rA) as template and 'activated' DNA is not effective.
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PMID:Authentic reverse transcriptase is coded by jockey, a mobile Drosophila element related to mammalian LINEs. 171 78

Derivatives of rifamycin-SV with substituted cyclic-amine side chains in position 3 of the ansa ring are strong inhibitors of RNA-directed DNA and DNA-directed DNA polymerase activity of RNA tumor viruses of murine, feline, and avian origin. Among 37 3-amine derivatives of rifamycin-SV that were tested, 29 3-cyclic amine derivatives were good inhibitors of the viral polymerases. Especially active were 3-piperidyl derivatives of rifamycin-SV with cyclohexyl and cyclohexylalkyl substituents. Derivatives that were effective against the viral polymerase also blocked cell transformation by the murine sarcoma virus. A DNA-directed DNA polymerase preparation from human KB cells was less sensitive to inhibition by these derivatives than the virion polymerase.
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PMID:3-Cyclic amine derivatives of rifamycin: strong inhibitors of the DNA polymerase activity of RNA tumor viruses. 433 89

Studies have shown that certain strain-specific characters of large, free-living amoebae may be influenced by the microinjection of non-homologous low molecular weight RNAs. To investigate the mechanisms involved in 'information' transfer, the template preferences of partially purified DNA polymerase activities isolated from Amoeba discoides have been studied. After passage through Sephadex G-200, DNA polymerase activities from whole homogenates could utilize both 'activated' calf thymus DNA and the synthetic ribohomopolymer poly rA oligo d(pT)10 as templates. Fractionation using different saturations of (NH4)2SO4 showed that there was no detectable poly A d(pT)10-directed DNA polymerase activity in the extra-mitochondrial cytoplasm, and the ability to utilize this template appeared to be located in the nuclei. Nuclear protein passed through short (30 cm) columns of Sephadex G-200 showed DNA polymerase activities which could use both synthetic and natural RNA as templates, but little activity was detected when using longer (70 cm) columns, although DNA-directed DNA polymerase activities were more clearly defined. Use of DEAE-cellulose only revealed a low (1--3%) activity with poly A d(pT)10 compared to the activity observed using 'activated' calf thymus DNS. DNA polymerase activities of amoebae showed a response to added RNA templates which depended on the purity of the enzyme preparation, and the possibility that these enzymes are involved in 'information' transfer cannot be ruled out.
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PMID:Informational molecules in amoebae studies of template utilization by the DNA polymerase activities of Amoeba discoides. 615 39


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