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)

In the post-mitochondrial fraction of murine LBN/b leukemic cells, four fractions with DNA polymerase activity (I, II, III, IV) were found. On the basis of ion exchanger affinity and poly(A), poly(C) and poly(Cm) replication ability, fraction I was classified as RNA-directed DNA polymerase of viral origin. On the basis of the differences in the ion exchanger affinity, molecular weight, template requirement, pH-dependence of enzymatic activity and NaCl concentration, divalent ion requirements and susceptibility to N-ethylmaleimide inhibition, fractions II, III and IV were classified as DNA-directed DNA polymerases beta, alpha and gamma, respectively. Three fractions, i.e. reverse transcriptase, and DNA-directed DNA polymerases beta and gamma, were found to incorporate dTMP on a poly(A)-oligo(dT) template-primer. Despite the similarity of the reaction of DNA polymerases beta and gamma with poly(A)-oligo(dT), some other properties of these enzymes suggest that they represent distinct enzymatic entities.
Acta Biochim Pol 1976
PMID:DNA polymerases of murine LBN/b leukemic cells. 5

The possible role of DNA polimerase III in conjugation was studied in a series of mutants temperature-sensitive for DNA polymerase III synthesis. The temperature-sensitive DNA mutation called dnaE 486 (ts) prohibits vegetative DNA replication at 41-45 degrees. Transfer of episome and chromosome from temperature-sensitive donor, carrying dnaE mutation to wild-type recipient strains, revertants and dnaE recipients was investigated. In the first two cases the number of Lac+ sexductants being even slightly higher at 43 degrees. Conjugational synthesis accompanying transfer involving the combination of dnaE (ts) thymine dependent and thymine independent donor and recipient strains measured by incorporation of 14C thymine was observed at the restrictive temperature. In the case of conjugation with temperaturesensitive recipient strains a drop of Lac+ sexductants and Pro+ recombinants may be as a result of disturbances in the synthesis of complementary strand in recipient, known to be dependent on pol III. However, the episome investigated by centrifugation in neutral CsC1 gradient after its transfer to the recipient with faulty polymerase III was double stranded (replicated) at the restrictive temperature.
Acta Microbiol Pol 1976
PMID:The role of polymerase III in conjugation between E. coli K12 donor and recipient strains carrying dnaE ts mutation. 5 32

Two diol epoxides of benzo(a)pyrene (BP), and benzo(a)pyrene 4,5-oxide, have been used to make adducts in the homopolymers polyribocytidylic acid, (rC); polyriboadenylic acid (rA), polydeoxycytidylic acid (dC) and polydeoxyadenylic acid (dA). With appropriate oligomers as primers these modified and unmodified polynucleotides were used as templates for DNA synthesis with avian myeloblastosis virus DNA polymerase (AMV) or E. coli Pol I DNA polymerase. We have found that: (1) the size of the DNA product is not markedly decreased by the presence of these these polycyclic aromatic hydrocarbon adducts in the templates; (2) the presence of adducts does not lead to increased incorporation of erroneous bases. These results, supported by kinetic data, suggest that these polymerases can bypass a site containing an adduct on the template without leaving a gap or causing misincorporation of a base and they imply that mutagenesis by BP may not be attributable to either of these mechanisms.
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PMID:Effects of benzo(a)pyrene adducts of DNA synthesis in vitro. 8 90

In vivo studies of PBS2 phage replication in a temperature-sensitive Bacillus subtilis DNA polymerase III (Pol III) mutant and a temperature-resistant revertant of this mutant have suggested the possible involvement of Pol III in PBS2 DNA synthesis. Previous results with 6-(p-hydroxyphenylazo)-uracil (HPUra), a specific inhibitor of Pol III and DNA replication in uninfected cells, suggest that Pol III is not involved in phage DNA replication, due to its resistance to this drug. Experiments were designed to examine possible explanations for this apparent contradiction. First, assays of the host Pol III and the phage-induced DNA polymerase activities in extracts indicated that a labile Pol III did not result in a labile phage-induced enzyme, suggesting that this new polymerase is not a modified HPUra-resistant form of Pol III. Indeed the purified phage-induced enzyme was resistant to the active, reduced form of HPUra under all assay conditions tested. Since in vitro Pol III was capable of replicating the uracil-containing DNA found in this phage, the sensitivity of the purified enzyme to reduced HPUra was examined using phage DNA as template-primer and dUTP as substrate; these new substrates did not affect the sensitivity of the host enzyme to the drug.
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PMID:Relationship of Bacillus subtilis DNA polymerase III to bacteriophage PBS2-induced DNA polymerase and to the replication of uracil-containing DNA. 10 52

A DNA-binding protein has been purified from nuclei of 3T3 cells infected with polyoma virus. The assay used to detect this activity measures the amount of double-stranded DNA retained on a nitrocellulose membrane filter in the presence of binding protein. The interaction between DNA and protein is salt dependent and occurs optimally at 0.8 M NaCl. The isolated protein can bind to both circular and linear duplex DNA. Incubation of the binding protein with PM2 or polyoma DNA results in the formation of a fast sedimenting DNA structure in neutral sucrose gradients. The isolated binding protein is also capable of producing a considerable stimulation of both Escherichia coli (Pol I) and T4 DNA polymerase activities when either single-stranded or intact, native T7 DNA is used as the template. The binding protein itself is free of detectable DNA polymerase or nuclease activity.
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PMID:Partial purification and properties of a DNA-binding protein from nuclei of cells infected with polyoma virus. 17 25

DNA polymerase I (Pol I) purified from a strain carrying polA12 demonstrates a defect primarily in the polymerase portion of the molecule. The mutant enzyme is altered in its structure and template specificity. Pol I isolated from strains carrying polAexl are primarily defective in 5' in equilibrium 3' exonuclease. The polAexl lesion renders strains conditonally lethal.
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PMID:Two temperature-sensitive polA mutants: an approach to the role in vivo of DNA polymerase I. 24 13

1. DNA polymerase gamma from the cytoplasmic fraction of rabbit intestinal epithelial cells has been purified 120 000-fold and was free of phosphatase and nuclease activities towards deoxyribonucleoside-5'-triphosphates and polynucleotides. 2. The enzyme exhibited maximal activity for activated DNA and poly(A) . oligo(dT)12--18 at pH 8.5 IN 0.25 AND 0.15 M-KCl, respectively. Km values for dTTP with these two templates were 0.5 and 3.8 microM, respectively. 3. In contrast to DNA polymerases alpha and beta, the enzyme replicated poly(A) . oligo(dT)12--18 10 times faster and poly(dA) . oligo(dT)12--18 5 times slower than activated DNA. 4. DNA polymerase gamma did not replicate poly(C) . oligo(dG)12--18 or poly(Cm) . oligo(dT)12--18. The reaction with poly(I) and poly(U) did not exceed 1% of that observed with poly(A). 5. The enzyme was inhibited in 60% by antiserum against DNA polymerase gamma from human lymphoblasts. 6. The nuclear fraction of rabbit intestinal epithelial cells contained DNA polymerase gamma with the same characteristics.
Acta Biochim Pol 1979
PMID:Purification and properties of DNA polymerase gamma from rabbit intestinal epithelial cells. 54 57

Sedimentation analysis of glycerol-density gradients has shown that freshly purified DNA polymerases A and B (pol A and pol B) of Euglena gracilis have molecular weights of 185,000 (8.7S) and 240,000 (10.3S) respectively. They can aggregate in fresh preparations to give forms of higher molecular weight as shown by gel filtration through Sepharose 6B, but on ageing pol B progressively generates species with sedimentation coefficients of 7.4-7.7S, 6.3-6.5S, 4.8S and finally 3.0S. Pol A apparently behaves in a similar fashion though it is unstable. Exposure of pol A and pol B to high ionic strengths can also cause their breakdown to species with lower sedimentation coefficients. The mitochondrial DNA polymerase is distinct, having a molecular weight of 170,000. It is proposed that pol A and pol B are oligomers of the 3.0S subunit and possibly other dissimilar subunits, with pol B having additional factors conferring upon it its extra catalytic functions.
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PMID:DNA polymerases of Euglena gracilis: heterogeneity of molecular weight and subunit structure. 80 92

The subcellular location and growth stage dependence of the DNA polymerases of Euglena gracilis strain Z and of a bleached derivative of the strain have been studied by fractionation of the enzymes from extracts of whole cells and subcellular fractions on DEAE-cellulose. A new method for the rapid isolation of nuclei was employed. Of the major enzymes, pol A has a predominantly nuclear location and pol B a predominantly cytoplasmic location. Pol A is 4-fold and pol B 15-fold more active in exponentially-growing cells than in stationary-phase cells, pol B representing 90% of the combined activities in exponential-phase cells. The activity of the mitochondrial DNA polymerase increases about 3-fold as the cells enter stationary phase while that of the chloroplast DNA polymerase is greater in exponential-phase cells. The chloroplast enzyme persists in cells which have been reversibly bleached. The results are compared to those of similar experiments involving primitive and higher eucaryotes.
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PMID:Subcellular location and growth stage dependence of the DNA polymerases of Euglena gracilis. 81 Jun 22

The reverse mutation to the wild type of lambda sus 9 and T4 AM B17 bacteriophages, grown in bacteria prelabeled with 35S and stored at--196 degrees, was studied. No mutagenic effect of 35S was observed in both, lambda and T4 bacteriophages. It is suggested that there is no influence of 35S disintegrations on the properties of DNA polymerase to which the mutagenic activity could be attributed.
Acta Microbiol Pol A 1975
PMID:Effects of disintegration of incorporated 35S on mutation frequency. 109 Jan 13


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