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)

In vaccinia virus infected cells the appearance of a late enzyme RNA polymerase was prevented by MPB, an inhibitor of nucleolar RNA synthesis, although inductions of the early enzymes thymidine kinase and DNA polymerase were not affected. It is inferred the nucleoli may be involved in the replication of vaccinia virus.
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PMID:Failure of poxvirus replication in the presence of an inhibitor of nucleolar RNA synthesis. 85 97

The inherent infidelity of Taq DNA polymerase in the polymerase chain reaction was exploited to produce random mutations in the trp A gene. Screening of the resulting clones allowed selection of non-interactive mutant alpha subunits retaining their intrinsic catalytic activity. Two single changes responsible for this phenotype were identified by DNA sequencing as: alpha 126 valine (GTG)----glutamic acid (GAG) and alpha 128 valine (GTT)----aspartic acid (GAT). Three single changes giving a non-interactive phenotype with an impaired intrinsic catalytic activity were identified by DNA sequencing as alpha 66 asparagine (AAC)----aspartic acid (GAC); alpha 109 lysine (AAA)----arginine (AGA); alpha 118 cysteine (TGC)----arginine (CGC). Where possible, we individually assessed the importance of these residues in alpha beta interaction in light of structural information from X-ray crystallography and by intergeneric protein sequence comparison.
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PMID:Selection and analysis of non-interactive mutants in the Escherichia coli tryptophan synthase alpha subunit. 160 55

The process of carcinogenesis is initiated by mutagenesis, which often involves replication past damaged DNA. One question - what exactly is a DNA polymerase seeing when it incorrectly copies a damaged DNA base (e.g., inserting dATP opposite a dG adduct)? - has not been answered in any case. Herein, we reflect on this question, principally by considering the mutagenicity of one activated form of benzo[a]pyrene, (+)-anti-B[a]PDE, and its major adduct [+ta]-B[a]P-N(2)-dG. In previous work, [+ta]-B[a]P-N(2)-dG was shown to be capable of inducing>95% G-->T mutations in one sequence context (5'-TGC), and approximately 95% G-->A mutations in another (5'-AGA). This raises the question - how can a single chemical entity induce different mutations depending upon DNA sequence context? Our current working hypothesis is that adduct conformational complexity causes adduct mutational complexity, where DNA sequence context can affect the former, thereby influencing the latter. Evidence supporting this hypothesis was discussed recently (Seo et al., Mutation Res. [in press]). Assuming this hypothesis is correct (at least in some cases), one goal is to consider what these mutagenic conformations might be. Based on molecular modeling studies, 16 possible conformations for [+ta]-B[a]P-N(2)-dG are proposed. A correlation between molecular modeling and mutagenesis work suggests a hypothesis (Hypothesis 3): a base displaced conformation with the dG moiety of the adduct in the major vs. minor groove gives G-->T vs. G-->A mutations, respectively. (Hypothesis 4, which is a generalized version of Hypothesis 3, is also proposed, and can potentially rationalize aspects of both [+ta]-B[a]P-N(2)-dG and AP-site mutagenesis, as well as the so-called "A-rule".) Finally, there is a discussion of how conformational complexity might explain some unusual mutagenesis results that suggest [+ta]-B[a]P-N(2)-dG can become trapped in different conformations, and why we think it makes sense to interpret adduct mutagenesis results by modeling ds-DNA (at least in some cases), even though the mutagenic event must occur at a ss/ds-DNA junction in the presence of a DNA polymerase.
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PMID:Toward an understanding of the role of DNA adduct conformation in defining mutagenic mechanism based on studies of the major adduct (formed at N(2)-dG) of the potent environmental carcinogen, benzo[a]pyrene. 1083 33

DNA diagnostic has been moving from expensive, low-throughput, multistep methods to inexpensive, higher throughput, closed-tube, and automated methods. Fluorescence is the favored signaling technology for such assays. In this method, we describe a universal molecular beacon (U-MB) as the fluorescent tracer in the real-time PCR technique. A 5'-universal template primer (5'-UT primer) has been designed with a tail in complementary to the loop and 5'-side arm sequence of U-MB at the 5'-end of forward target specific primer. As PCR cycles increase, a new DNA fragment with a 5'-UT primer tail is synthesized, which is used as the template for next PCR cycle. As the reverse primer extends to the 5'-UT primer tail, the U-MB hybridized is displaced and the fluorescence from the fluorophore of the U-MB is quenched, indicating that the allele-specific PCR is in progress. This tracing system combined with an allele-specific reverse primer and vent (exo-) DNA polymerase, a polymerase that lacks 3'- to 5'-exonuclease activity, was used for the detection of point mutations of base G in codon 259 (AGA) of exon 7 of p53 gene on a panel of breast cancer individuals.
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PMID:Universal molecular beacon-based tracer system for real-time polymerase chain reaction. 1710 84

A newly designed ligand, methylcarbamoylnaphthyridine dimer (MCND), was synthesized and characterized. Ligand binding to d(GAA)(10) was investigated by UV thermal denaturation, circular dichroism spectroscopy, surface plasmon resonance, and cold-spray-ionization time-of-flight mass spectrometry. The results indicated that MCND bound to the d(GAA)(n) repeat to form a stable hairpin structure with a major binding stoichiometry of 3:1. The most likely binding site was identified as the G-G mismatch in the AGA/AGA triad. The polymerase stop assay showed that MCND binding to the d(GAA)(n) repeat effectively interfered with the extension of the primer at the first two GAA sites on the template with both prokaryotic Taq DNA polymerase and human DNA polymerase alpha.
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PMID:A small molecule affecting the replication of trinucleotide repeat d(GAA)n. 1971 22