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

We have reviewed our recent evidence for the following scheme for synthesis and integration of viral DAN after infection of permissive cells by ASV: Within the first 3 hours of infection, duplex, virus-specific DNA the length of a subunit of the viral genome (3 times 10(6) daltons) is synthesized in the cytoplasm of infected cells by a virion-associated DNA polymerase; viral DNA probably forms a covalently closed circular duplex prior to integration into host nuclear DNA. Integration and the usual consequences of viral infection can be inhibited by ethidium bromide. We have described a number of features of viral DNA prior to its integration and have indicated how these features can be exploited in the purification of viral DNA. Viral DNA has also been measured in nonpermissive (mammalian) cells in which the variable expression of viral genes is controlled by unknown mechanisms.
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PMID:Synthesis, structure and function of avian sarcoma virus-specific DNA in permissive and nonpermissive cells. 5 Sep 3

We have analyzed and compared the responses of the three major HeLa cell DNA polymerases (alpha, beta, and gamma) to a HeLa DNA template with short RNA or DNA primers hybridized to it. Only DNA polymerase alpha is able to synthesize DNA covalently bonded to the RNA primer via a 3' yields 5' phosphodiester bond. 32P transfer experiments showed that all combinations of ribo- and deoxyribonucleotides are represented in the RNA-DNA linkages but their distribution is nonrandom. The RNA-DNA linked molecules base-paired to a HeLa DNA template strand represent a possible "natural" in vitro primer-template for DNA polymerases and can be extended by all three DNA polymerases (alpha, beta, and gamma). These findings indicate that DNA polymerases beta and gamma are capable of DNA-primed but not RNA-PRIMED DNA synthesis, while DNA polymerase alpha is capable of both RNA-primed and DAN-primed DNA synthesis.
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PMID:RNA-primed DNA synthesis: specific catalysis by HeLa cell DNA polymerase alpha. 105 33

Exonuclease V (the recBC enzyme) of Escherichia coli can release pyrimidine dimers from ultraviolet-irradiated linear duplex DNA though it acts more slowly on irradiated DNA than on non-irradiated DAN. However, close circular lambda-dv DNA or phi X174 replicative form I DNA is not attacked by exonuclease V even though the DNA has been irradiated and treated with T4 endonuclease V to produce single-stranded breaks at the 5'-side of pyrimidine dimers. When irradiated circular DNA, previously nicked by T4 endonuclease V, is briefly exposed to elevated temperature, the DAN becomes susceptible to the action of exonuclease V, and pyrimidine dimers are selectively released. The increased susceptibility to exonuclease V may be resulted from locarized denaturation, or "fraying" of the 5'-termini at the nicks. The preferential release of pyrimidine dimers was observed when irradiated DNA, treated with T4 endonuclease V, was incubated with crude extracts of Escherichia coli. The activity was found in various strains defective in exonuclease V and/or DNA polymerase I.
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PMID:Action of exonuclease V (the recBC enzyme) on ultraviolet-irradiated DNA. 109 Dec 99

We found that hydroxylation occurs at the C-2 position of adenine by oxygen radical treatment (Fe2+-EDTA) of dA, dATP, and single- and double-stranded DNA. This oxidatively damaged base, 2-hydroxyadenine, was produced 3-6-fold and 40-fold less than 8-hydroxyguanine when monomers and polynucleotides, respectively, were treated. To determine whether the damaged nucleotide, 2-hydroxydeoxyadenosine triphosphate (2-OH-dATP), is incorporated into a growing DNA, and to reveal the kinds of nucleotides opposite which 2-OH-dATP is incorporated, calf thymus DNA polymerase alpha and the Klenow fragment of Escherichia coli DNA polymerase I were used in vitro DAN synthesis in the presence of 2-OH-dATP. DNA polymerase alpha incorporated the nucleotide opposite T and C in the DNA template. On the other hand, in an experiment using the Klenow fragment, incorporation of 2-OH-dATP was observed only opposite T. Steady-state kinetic studies indicated that incorporation of 2-OH-dATP by DNA polymerase alpha opposite T was favored over that opposite C by a factor of only 4.5. These results indicate that 2-OH-dATP, an oxidatively damaged nucleotide, is a substrate for DNA polymerases and is incorporated incorrectly by the replicative DNA polymerase.
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PMID:Formation of 2-hydroxydeoxyadenosine triphosphate, an oxidatively damaged nucleotide, and its incorporation by DNA polymerases. Steady-state kinetics of the incorporation. 764 27