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

We have isolated a protein fraction from HSV-1 infected cells which binds specifically to single-stranded DNA, facilitates a lowering of the melting temperature of poly[d(A-T)] and specifically stimulates the activity of the homologous virus-induced DNA-dependent DNA polymerase in vitro. These are major characteristics of a helix-destabilising protein, exemplified by the prokaryotic gene 32 protein.
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PMID:A helix-destabilising protein from herpes simplex virus type I infected cells which specifically stimulates the virus induced DNA polymerase activity in vitro. 631 6

An in vitro system which replicates plasmid DNA containing the replication origin of adenovirus DNA has been established. Replication of plasmid pLA1 DNA, which contains the left-hand terminus (0-9.4 map units) of adenovirus serotype 5 DNA but which lacks the 55,000-dalton terminal protein, is initiated by a protein-primed mechanism in a manner similar to that found with adenovirus DNA. Initiation of DNA replication using plasmid pLA1 as a template requires (i) that the cloned adenovirus sequence be present at the terminus of a linearized (form III) DNA molecule ( Tamanoi , F., and Stillman , B. W. (1982) Proc. Natl. Acad. Sci. U. S. A., 79, 2221-2225; van Bergen, B. G. M., van der Ley , P. A., van Driel , W., van Mansfield , A. D. M., and van der Vliet , P. A. (1983) Nucleic Acid Res. 11, 1975-1979), and (ii) the presence of the 80,000-dalton precursor to the 55,000-dalton terminal protein and the adenovirus coded DNA-dependent DNA polymerase. In the presence of the four deoxy-nucleoside triphosphates, the preterminal protein, the adenovirus coded DNA binding protein, and an extract prepared from uninfected HeLa nuclei, the adenovirus DNA polymerase can elongate the preterminal-protein dCMP initiation complex formed on pLA1 DNA to full length (6.6 kilobase) DNA molecules. These results suggest that the 55,000-dalton terminal protein covalently linked to the 5' termini of adenovirus DNA is not essential for the replication of this DNA.
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PMID:Protein-primed replication of plasmids containing the terminus of the adenovirus genome. I. Characterization of an in vitro DNA replication system dependent on adenoviral DNA sequences. 633 82

A DNA hybridization assay was used to detect hepatitis B virus (HBV)-specific DNA sequences in extracted sera obtained from chimpanzees infected with HBV, hepatitis A virus (HAV), and a factor VIII-derived non-A/non-B (NANB) agent. The results did not reveal any HBV-DNA homology with sera obtained from animals infected with HAV or factor VIII-derived NANB. Sera obtained from two HBV-infected chimpanzees demonstrated that HBV-specific DNA could be detected during the acute phase of the disease. In addition, an HBV-specific DNA-dependent DNA polymerase assay did not demonstrate any statistically significant activity in 12 of 12 NANB acute-phase specimens or in 6 of 6 NANB chronic-phase specimens. These results suggest that the factor VIII-derived NANB agent is unrelated to HBV.
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PMID:Unrelatedness of factor VIII-derived non-A/non-B hepatitis and hepatitis B virus. 640 66

The RNA genome of potato spindle tuber viroid (PSTV) is transcribed in vitro into complementary DNA and RNA by DNA-dependent DNA polymerase I and RNA polymerase, respectively, from Escherichia coli. In vitro synthesis of complementary RNA produces distinct transcripts larger than unit length thus reflecting the in vivo mechanism of viroid replication. The influence of varying experimental conditions on the transcription process is studied; actinomycin D is found to drastically reduce complementary RNA synthesis from the PSTV RNA template by RNA polymerase.
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PMID:Viroid RNA is accepted as a template for in vitro transcription by DNA-dependent DNA polymerase I and RNA polymerase from Escherichia coli. 676 Sep 14

Effects of VA-2, a component of quinoid antibiotic M-92, on the incorporation of radioisotope-labeled compounds into the cells of Staphylococcus aureus were studied. Deoxyribonucleic acid (DNA) synthesis was immediately inhibited by the addition of VA-2. Significant inhibitions of ribonucleic acid and protein syntheses and minor reduction of peptidoglycan synthesis were observed after a short delay. VA-2 immediately induced the degradation of DNA prelabelled with [14C]thymidine in the cells of S. aureus. In the examinations using E. coli enzyme and calf thymus DNA as a template, VA-2 prevented DNA-dependent DNA polymerase reaction. The inhibition of DNA polymerase I reaction was fairly reversed by increasing the concentration of template DNA, but slightly by that of the enzyme. Agarose gel electrophoresis showed that VA-2 elicited an extensive cleavage of PM2 cccDNA. VA-2 caused a primary conversion of the cccDNA to ocDNA at a low concentration (0.2 micrograms/ml), while at high concentrations (2.0 and 20 micrograms/ml) it cleaved the cccDNA to ocDNA and linear DNA progressively. These cleavages were observed even at 0 degrees C as well as at 37 degrees C, and were enhanced with the addition of a reducing agent such as 2-mercaptoethanol or sodium borohydride.
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PMID:Studies on a new antibiotic M-92 produced by micromonospora. V. Mechanism of action of the component VA-2. 685 68

At least 12 virus-induced DNA-binding proteins with mol. wt. ranging from 14 X 10(3) have been isolated from frog virus (FV 3)-infected fathead minnow cells by DNA affinity chromatography. Two enzymic activities, DNA-dependent DNA polymerase and endodeoxyribonuclease, were present in the DNA-binding proteins; these enzymic activities were similar to those induced by FV 3 in infected cells. A single species of DNA-binding proteins with a mol. wt of 36 000 had very high affinity for single-stranded DNA, but a low one for double-stranded DNA. Proteins with such characteristic affinity for single-stranded DNA destabilize the DNA helix and are essential for viral DNA replication. Thus, the 36 000 mol. wt. DNA-binding protein is a candidate for such a role in FV 3 DNA replication.
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PMID:DNA-binding proteins in frog virus 3-infected cells. 689 83

The chemicals 9, 10-dimethylbenzanthracene (DMBA), ethionine, daunorubicin, actinomycin D, 1-(2-chloroethyl-1)-nitrosourea (CCNU), steroids, croton oil and dimethyl-sulfoxide (DMSO) were used in order to correlate their effect on the in vitro synthesis of normal and cancer DNA, on DNA strand separation and on accelerated in vivo multiplication of cancer cells. All of the compounds tested strongly stimulate the synthesis of cancer DNA in vitro catalyzed by DNA-dependent DNA polymerase I and measured as an acid-precipitable labeled product. Under the same conditions, the synthesis of DNA originating from healthy tissues is only slightly enhanced, except in the case of croton oil and DMSO. These substances are almost equally active on cancer and normal DNA. Although both cancer and normal DNA contain a large amount of double-stranded regions, the extent of DNA strand separation measured by the increase in UV absorbance (hyperchromicity) in the presence of each compound tested is much higher for all cancer DNA than for corresponding normal DNA. In contrast, DMSO and croton oil do not appear to distinguish cancer DNA from normal DNA. Additive and differential effects of various compounds on cancer DNA strand separation can be observed. Small doses of DMBA and CCNU stimulate the multiplication of Ehrlich ascites tumor cells in vivo in mice. There is thus a possible correlation between DNA strand separation, DNA synthesis, multiplication and differentiation of cancer cells in the presence of the above compounds, which is different from the response of normal cells to these compounds.
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PMID:Correlation between in vitro DNA synthesis, DNA strand separation and in vivo multiplication of cancer cells. 725 Apr 82

We have investigated the effects of estrogens and antiestrogens on cellular DNA-dependent DNA polymerase activity in human breast cancer, using as a model the MCF-7 human breast cancer cell line which contains estrogen receptor. 17 beta-Estradiol had little if any effect on cytosol DNA polymerase activity or growth (total DNA per flask) of MCF-7 cells. Incubation of the cells for 4 to 6 days with the antiestrogen nafoxidine, however, resulted in a dose-dependent reduction in cytosol DNA polymerase activity to one-half that observed in untreated cells. Enzyme activity in antiestrogen-treated cells was restored to levels contained in untreated cells by removing antiestrogen from the growth medium and incubating the cells for an additional 4 days with 17 beta-estradiol. The restoration required estrogenic steroids specifically, and the time course, magnitude, and dose dependence of the response were similar to estrogen-stimulated increases in DNA polymerase activity described in other estrogen target tissues. Estrogen-mediated reversal of antiestrogen suppression of DNA polymerase activity was paralleled by increases in total DNA synthesis.
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PMID:Effects of estrogen and antiestrogen on DNA polymerase in human breast cancer. 737 Oct 1

The unperturbed cell kinetics of 13762 mammary tumors in Fischer 344/CRBL rats were studied by fraction labeled mitoses (FLM) and in vitro methods. The 3H-thymidine (3H-TdR) labeling index (LI) was 32.5% and the volume doubling time was approximately 96 hours 14 days after inoculation. The cell cycle, G1, G2, and DNA synthesis times by computer analysis of the FLM data were 11.5, 3.5, 1.3, and 5.4 respectively. The primer available DNA-dependent DNA polymerase labeling index (69%) was similar to the growth fraction calculated from the FLM data. Estimates of cell kinetic parameters from this tumor model, by in vitro methods, were very similar to those obtained by FLM analysis. The effect of Adriamycin (Adr) on the cell kinetics of 13762 tumors was also studied by monitoring the changes in the 3H-TdR LI, the primer available DNA-dependent DNA polymerase labeling index, and the flux of cells from S to G2 phase by the 3H-TdR and 14C-TdR double-labeling method. The results indicated that cell proliferation was inhibited for at least 3 days after 5 mg/kg of Adr. Recovery of cell proliferation was noted between Days 4 and 7 after treatment. Sequential chemotherapy with cyclophosphamide was most effective when administered to coincide with the proliferative recovery after Adr.
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PMID:Effect of adriamycin on the cell kinetics of 13762 rat mammary tumors and implications for therapy. 740 64

Using a computer-assisted molecular modeling protocol, we have completed the three-dimensional structures of HIV-1 reverse transcriptase and the Klenow fragment of DNA polymerase I based on the C alpha crystal coordinates of the individual enzymes. The two model-built structures were then used to compare the electrostatic potential contours and analyze the spatial positions of residues conserved in the catalytic domains of the two enzymes. In spite of rather weak sequence similarity and different folding patterns between the DNA-dependent DNA polymerase (pol I) and the RNA-dependent DNA polymerases (RT), we have noted the occurrence of identical or similar residues at common spatial positions in pol I and RT in a three-dimensional context. The homologous residues present at equivalent spatial position in the Klenow fragment and the p66 subunit of HIV-1 RT may therefore imply their functional similarity. Furthermore, these conserved residues may represent a similar structure-function feature in all polymerases.
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PMID:A computer-assisted analysis of conserved residues in the three-dimensional structures of the polymerase domains of Escherichia coli DNA polymerase I and HIV-1 reverse transcriptase. 750 63


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