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

---

Query: EC:2.7.7.7 (DNA polymerase)
17,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A new DNA polymerase was partially purified from cell-free extracts of a continuous rat cell-line (XC). The XC cells had been transformed by the Prague strain of Rous sarcoma virus but did not produce infectious virus. The molecular weight of the DNA polymerase is 70,000, as estimated by glycerol gradient centrifugation and by Sephadex gel filtration. This enzyme can be distinguished from the other cellular DNA polymerases by its elution pattern on DNA-cellulose column chromatography, its molecular weight, and its primer-template specificity. The enzyme has some characteristics of the murine leukemia virus reverse transcriptase. It is partially inhibited by immunoglobulin G purified from rabbit antiserum prepared against Rauscher leukemia virus reverse transcriptase, but is not inhibited by IgG from rat antiserum prepared against avian myeloblastosis virus reverse transcriptase. However, the XC cell enzyme can be distinguished from the murine leukemia virus reverse transcriptase by its inefficiency in copying an oligo(dG)12-poly(rC)primer-template.
...
PMID:Partial purification and characterization of DNA polymerases from a Rous sarcoma virus-transformed rat cell line. 17 Sep 87

Varying the concentration of Triton X-100, a nonionic detergent used to promote the DNA polymerase activity of Rous sarcoma virus in an endogenous reaction, showed a very sharp peak at about 0.02% (vol/vol) for optimal DNA synthesis. The yield of DNA at this concentration of Triton exceeded yields obtained at concentrations above the optimum by a factor of 2-5 for the 90-min reaction. At optimal Triton concentration, about 1-7% of the DNA made in the absence of actinomycin and about 4-10% of the DNA made in the presence of actinomycin was 2.5 X 10(6) daltons or greater, as estimated by formamide polyacrylamide gel electrophoresis and by alkaline sucrose gradient sedimentation. No large DNA was obtained at higher than optimal Triton concentrations. The large DNA molecules were rendered totally resistant to single-strand specific nuclease S1 after hybridization to an excess of viral RNA. It was concluded that at optimal detergent concentration, the viral DNA polymerase can synthesize full-size DNA transcripts of viral RNA.
...
PMID:In vitro synthesis of full-length DNA transcripts of Rous sarcoma virus RNA by viral DNA polymerase. 17 81

Analyses of the DNA polymerase present in the inner mitochondrial membrane and matrix fraction of the mitochondria isolated from Rous sarcoma cells and chick embryo cells, and in the lysate of Rous sarcoma virus were performed, using a modification of the thin-layer gel filtration on Sephadex G-150 superfine. The method allowed the simultaneous determination of the molecular weight of the isolated enzymes. In the mitochondria or Rous sarcoma cells an RNA-directed DNA polymerase, activated by poly(rA): oligo (dT) synthetic duplex, was detected, with the same molecular weight as the reverse transcriptase isolated from Rous sarcoma virus. Such enzyme was not found in the mitochondria of chick embryo cells.
...
PMID:Detection of RNA-instructed DNA polymerase in the mitochondria of Rous sarcoma cells using sephadex G-150 thin-layer gel filtration. 17 3

8-Hydroxyquinoline and several of its derivatives inactivate the transforming ability of Rous sarcoma virus and inhibit its ribonucleic acid-dependent deoxyribonucleic acid polymerase activity. The copper complex of these metal-binding ligands is as active as the free ligand. The activity of the 8-hydroxyquinolines is approximately 50-fold more effective than another group of metal-binding compounds that we have tested, the thiosemicarbazones. In contrast to the potency of the 8-hydroxyquinolines to inactivate Rous sarcoma virus, no intracellular inhibition of transformation could be demonstrated at a concentration that did not affect the growth and appearance of the cells. Cellular deoxyribonucleic acid synthesis was inhibited to a greater extent than was ribonucleic acid or protein synthesis. The phenomenon of "concentration quenching" was observed with high concentrations of drug, causing less inhibition of deoxyribonucleic acid synthesis than was observed with lower concentrations. Herpes simplex virus type 1 was inactivated also by the 8-hydroxyquinolines and their copper complexes. No intracellular inhibition of plaque formation was observed. Treatment with 8-hydroxyquinoline sulfate had no effect on the resolution of herpetic keratitis in rabbits. Some 8-hydroxyquinolines bind to deoxyribonucleic acid in the presence of copper, a phenomenon that may be important in their antiviral activity.
...
PMID:Hydroxyquinolines inhibit ribonucleic acid-dependent deoxyribonucleic acid polymerase and inactivate Rous sarcoma virus and herpes simplex virus. 18 49

The RNase-T1-resistant oligonucleotides of two Prague Rous sarcoma viruses with temperature-sensitive (ts) DNA polymerases (DNA nucleotidyltransferases), termed ts LA 337 and 335 of one leukosis virus, RAV-6, and 20 of their recombinant progeny have been mapped relative to the 3' poly (A) terminus of the viral RNA. The resulting oligonucleotide maps have been ocrrelated with markers of the four known viral genetic elements encoded in the RNA of 10,000 nucleotides. In accord with previous results recombinant RNAs contained (i) oligonucleotides characteristic of the src gene, coding for sarcoma formation, between the poly(A) end and 2000 nucleotides and (ii) olignucleotides characteristic of the env gene, coding for the envelope glycoprotein, between 2500 and 5000 nucleo tides from the poly(A) end. (iii) A cluster of four oligonucleotides that mapped between 6000 and 8000 nucleotides from the 3' poly(A) end of each RNA was shared by both parental viruses and all recombinants. Since all other map segments of our recombinants failed to segregate with the ts- or wild-type markers of the parental DNA polymerase gene (pol), it was concluded that the ts pol lesion maps in this RNA segment. (iv) The 5' segment of each recombinant RNA contained a cluster of four to five oligonucleotides whose parental origin correlated with an electrophoretic marker of one of the parental virion proteins, p27, a major product of the viral gag gene. The gene order 5'-gag-pol-env-src-poly(A) is consistent with our data.
...
PMID:Mapping oligonucleotides of Rous sarcoma virus RNA that segregate with polymerase and group-specific antigen markers in recombinants. 18 81

The mechanism of transfection by Rous sarcoma virus DNA was investigated by assaying DNA-mediated transformation under conditions which restricted secondary virus infection. Chicken embryo fibroblasts which were genetically resistant to virus infection as a result of the absence of receptors for virus penetration were also resistant to transformation by integrated or unintegrated Rous sarcoma virus DNA. In addition, DNA of replication-defective Bryan hightiter Rous sarcoma virus was noninfectious, and transformation by DNA of a temperature-sensitive DNA polymerase mutant was temperature sensitive. These results indicated that secondary virus infection was necessary for transformation by Rous sarcoma virus DNA. Since transformation was assayed by colony formation in soft agar, as well as by focus formation, the requirement for secondary virus infection was not an artifact of potential difficulty in detection of foci formed by division of single transformed cells. Therefore, it appeared that donor DNA did not stably transform recipient cells by direct integration. Instead, the results were consistent with the hypothesis that transfection of chicken embryo fibroblasts by Rous sarcoma virus DNA proceeded by transcription of donor DNA, formation of extracellular progeny virus, and secondary virus infection of sensitive cells.
...
PMID:Mechanism of transfection of chicken embryo fibroblasts by Rous sarcoma virus DNA. 21 12

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.
...
PMID:Mode of action of 9-beta-D-arabinofuranosyladenine on the synthesis of DNA, RNA, and protein in vivo and in vitro. 114 31

Reverse transcription of the retroviral RNA genome begins with tRNA-primed synthesis of a minus-strand DNA, which subsequently acts as the template for the synthesis of plus-strand DNA. This plus-strand DNA is initiated at a unique location and makes use of a purine-rich RNA oligonucleotide derived by RNase H action on the viral RNA. To determine the variables that are relevant to successful specific initiation of plus-strand DNA synthesis, we have used nucleic acid sequences from the genome of Rous sarcoma virus along with three different sources of RNase H: avian myeloblastosis virus DNA polymerase, murine leukemia virus DNA polymerase, and the RNase H of Escherichia coli. Our findings include evidence that specificity is controlled not only by the nucleic acid sequences but also by the RNase H. For example, while the avian reverse transcriptase efficiently and specifically initiates on the sequences of the avian retrovirus, the murine reverse transcriptase initiates specifically but at a location 4 bases upstream of the correct site.
...
PMID:Specificities involved in the initiation of retroviral plus-strand DNA. 168 26

Enzyme preparations of Rous sarcoma virus (RSV) reverse transcriptase have been isolated from a culture of E. coli HB101(pMF14). The enzyme has been purified to homogeneity and been shown to consist of two subunits, of molecular mass 97.4 and 61.3 kDa, respectively. The optimum conditions for the DNA polymerase and RNAase H activities, fidelity of DNA synthesis on a homogeneous RNA template, and the inhibitory effect of azidothymidine triphosphate have been determined. Data on the use of RSV recombinant reverse transcriptase for cDNA synthesis are given.
...
PMID:Recombinant reverse transcriptase of Rous sarcoma virus: characterization of DNA polymerase and RNAase H activities. 171 11

The enzymatic domains of the avian retrovirus polymerase (pol) gene have been mapped by the use of peptide antibodies and COOH-terminal amino acid analysis. The processed pol beta polypeptide is cleaved in vivo to yield alpha and pp32. Rabbit antibodies were directed against synthetic peptides whose sequence was deduced from the known pol sequence of Rous sarcoma virus, Prague C (Schwartz, D.E., Tizard, R., and Gilbert, W. (1983) Cell 32, 853-869). The RNase H active site of pol was located in the NH2-terminal region of the alpha DNA polymerase subunit. The COOH terminus of the alpha subunit was found to be immediately adjacent to the NH2 terminus of the pp32 pol protein. COOH-terminal amino acid analysis of pp32 revealed that this protein is also processed. From the deduced amino acid sequence of pol, it appears likely that pol encodes an additional 4100-dalton polypeptide located at its extreme COOH terminus. The enzymatic domains on beta appear to map in the following order: RNase H-DNA polymerase-DNA endonuclease. Hydrophilicity analysis and secondary structure predictions of wild type Rous sarcoma virus pol products and mutated pp32 possessing single amino acid changes permit further structural evaluation of the multifunctional pol protein.
...
PMID:Structural characterization of the avian retrovirus reverse transcriptase and endonuclease domains. 298 84


<< Previous 1 2 3 4 5 6 Next >>

---