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)

Several new analogues of the antiviral antibiotic distamycin A were synthesized and assayed for their effects on influenza and herpes simplex virus. The new compounds 5b-j (R1-3 = H, CH3, and C2H5, R4,5 = H and CH3) were obtained via stepwise prepared formylated trimeric benzyl 4-aminopyrrole-2-carboxylates 3a-h, which after catalytic hydrogenolysis were coupled as N-succinimidyl esters directly with the proper beta-aminopropionamidine, unsubstituted or substituted with one or two methyl groups in the amidine function. Most of the new analogues did not exhibit significant effects on the viruses studied, but three compounds (5f-h) displayed activity on herpes virus as demonstrated in plaque formation and virus yield assays. Elevated cytotoxicity was simultaneously observed for 5g and 5h. For compound 5f, a partial separation of antiherpes activity and cytotoxicity was accomplished. The differences in antiherpes activity did not correspond to the differences in the inhibition of herpes virus DNA polymerase.
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PMID:Synthesis and antiviral activity of distamycin A analogues: substitutions on the different pyrrole nitrogens and in the amidine function. 630 37

In eight patients with biopsy-confirmed chronic active hepatitis (CAH), hepatitis B e antigen (HBeAg) levels and DNA polymerase (DNA-P) activity were assayed three times a week for six weeks and once a week for another six weeks. HBeAg levels were rather constant, whereas DNA-P activity fluctuated. No correlation was observed between the quantities of HBeAg and DNA-P activity. An unexpected fluctuation in DNA-P activity was noted in all patients after an influenza vaccination.
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PMID:Quantitative relationship between HBeAg and DNA polymerase activity in sera from patients with chronic active hepatitis during a three-month period. 722 20

In nucleotide sequencing of the cDNA of the influenza virus PB2 polymerase gene by the dideoxy method using a modified T7 DNA polymerase, Sequenase, the sequence of the promoter region, 5'-AGCGAAAGCAGG, was shown to be misread as 5'-AGCGAAACGAGG, i.e., a GC doublet at positions 8 and 9 was read in reverse. This misreading was also found both when the sequence of BsmI restriction site upstream from the PB2 promoter sequence was exchanged by that of the promoter of T7 RNA polymerase and when the downstream region was substituted with the nonstructural (NS) protein gene. These results indicated that the misreading by Sequenase was attributed specifically to the PB2 promoter region, independent of the upstream and downstream sequences. The misreading, however, did not occur when dGTP in the labeling mixture was substituted with another nucleotide analog, dITP. Furthermore, the reversion did not occur in the NS gene promoter region, where the nucleotide sequence was 5'-AGCAAAAGCAGG. Since the nucleotide difference between the PB2 and NS promoter regions was only at the fourth residue, i.e., G for PB2 and A for PB2 and A for NS, the G residue followed by a triplet AAA in the PB2 promoter region was suggested to be a signal responsible for the misreading by Sequenase T7 DNA polymerase. The findings warns of possible misreading in determining DNA sequences, in addition to compression of the sequencing ladder.
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PMID:Reverse misreading of a GC doublet by the modified T7 DNA polymerase, Sequenase. 797 72

The nucleoside analog 2'-deoxy-2'-fluoroguanosine (2'-fluorodGuo) is phosphorylated by cellular enzymes and reversibly inhibits influenza virus replication in chick embryo cells within the first 4 h of infection. RNA hybridization studies revealed that primary and secondary transcription of influenza virus RNA were blocked at a compound concentration of 10 microM, but no inhibition of cell protein synthesis was seen even at high compound concentrations (200 microM). In vitro, the triphosphate of 2'-fluorodGuo is a competitive inhibitor of influenza virus transcriptase activity from disrupted virus, with a Ki of 1.0 microM. The cellular polymerases DNA polymerase alpha and RNA polymerase II were only weakly inhibited or were insusceptible to 2'-fluorodGTP. In kinetic studies with the influenza virus transcriptase, 2'-fluorodGTP, in the absence of GTP, blocked elongation of the virus RNA chain. Similarly, by using purified ribonucleoprotein complexes it was found that the addition of a single nucleotide of 2'-fluorodGTP to the virus RNA caused chain termination, which resulted in the blockage of further virus transcription. Furthermore, the specificity for influenza virus transcriptase was confirmed when the transcriptase from partially resistant virus was found to be 10-fold less susceptible to 2'-fluorodGTP (Ki = 13.1 microM).
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PMID:Inhibition of influenza virus transcription by 2'-deoxy-2'-fluoroguanosine. 858 25

The synthesis of influenza virus mRNA requires primers generated by cleavage of host cell transcripts 10-13 nucleotides from the 5' end by a virally encoded endonuclease. This novel enzyme is an attractive target for the development of antiviral agents. An assay for the influenza virus endonuclease has been developed that monitors the substrate cleavage reaction only at the correct position in the sequence, thereby discriminating against nonspecific RNA cleavage products. The influenza endonuclease assay is sensitive enough to detect 200 amol of product. The assay employs a DNA polymerase-catalyzed extension of the endonuclease cleavage product using radiolabeled dGTP and a DNA template containing a 3' region complementary to the product joined to a 5' region consisting of 10 dC residues. The influenza endonuclease assay does not involve gel electrophoretic separation and is amenable to high volume screening of potential inhibitors. The assay may also be employed to determine the site of influenza endonucleolytic cleavage in the substrate.
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PMID:Assay for influenza virus endonuclease using DNA polymerase extension of a specific cleavage product. 859 78

The recognition of viruses as causes of pneumonia in both immunocompetent and immunocompromised hosts has expanded dramatically. The number of therapeutic agents available for treatment of these illness also has increased in the last decade. Each of these agents has demonstrated a limited therapeutic indication for treatment of viral pneumonia. Many of these agents inhibit viral DNA synthesis through actions as nucleoside analogs (such as acyclovir and ganciclovir). However, a variety of alternative mechanisms of inhibition of viral replication are used. Ribavirin, while being a nucleoside analogue, also appears to exert broad antiviral activity by a variety of enzymatic inhibitory mechanisms. Foscarnet, an inorganic pyrophosphate analogue, offers additional treatment options for herpesviruses by acting as a direct virus DNA polymerase inhibitor. The tricyclic amines amantadine and rimantadine inhibit influenza A replication by interfering with viral uncoating after cell penetration. Thus, these two agents are largely effective as prophylaxis. The search for novel antiviral drugs, such as neuraminadases inhibitors with selective influenza activity, is currently in progress.
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PMID:Anti-infective therapy for viral pneumonia. 866 55

The pharmacology, pharmacokinetics, clinical efficacy, adverse effects, and dosage and administration of gemcitabine are reviewed. Gemcitabine is a deoxycytidine-analogue antimetabolite with activity against some solid tumors. Gemcitabine is phosphorylated intracellularly to difluorodeoxycytidine triphosphate, which terminates DNA-chain elongation and competitively inhibits DNA polymerase and ribonucleotide reductase. After i.v. administration, gemcitabine is rapidly distributed into total body water. The drug is deaminated in the plasma to inactive difluorodeoxyuridine; both gemcitabine and difluorodeoxyuridine are primarily renally eliminated. In clinical studies, gemcitabine reduced pain and improved function in patients with advanced pancreatic cancer. Gemcitabine has shown some activity against non-small-cell lung cancer, particularly when combined with cisplatin or ifosfamide. The agent has also shown modest activity against advanced ovarian and breast cancer. Adverse effects include dose-limiting myelosuppression, flu-like symptoms, nausea, vomiting, and rash. Gemcitabine has FDA-approved labeling for use in the treatment of locally advanced and metastatic pancreatic cancer. The recommended dosage for this indication is 1000 mg/m2 (as the hydrochloride salt) i.v. given over 30 minutes weekly for seven weeks, followed after one week of rest by 1000 mg/ m2 i.v. given over 30 minutes weekly for three weeks every four weeks. Gemcitabine palliates symptoms in patients with advanced or metastatic pancreatic cancer. More study is needed to determine gemcitabine's role in the treatment of non-small-cell lung cancer, ovarian cancer, and breast cancer.
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PMID:Gemcitabine: a cytidine analogue active against solid tumors. 911 4

An optimized reaction condition for amplification of influenza A virus RNA, by thermus thermophilus (Tth) DNA polymerase-based PCR, incorporating uracil N glycosylase (UNG) and dUTP in the reaction has been determined. dUTP could not be substituted for all dTTP sites when UNG was present in the reaction. The relative concentration of dUTP and dTTP has been optimized for allowing amplification of the target RNA. It has been verified that the amplified product DNA had sufficient dUTP and was digestable by UNG. Using the optimized reaction condition, influenza A virus-specific DNA fragment could be amplified and detected in 15 of 15 culture positive (for influenza A virus) nasopharyngeal specimens.
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PMID:Optimized PCR amplification of influenza A virus RNA using Tth DNA polymerase, incorporating uracil N glycosylase (UNG) in a single tube reaction. 940 50

The serial low-titer specimens of Influenza A virus and Adeno virus type 7 were tested for the presence of virus specific genes by PCR based on Tth DNA polymerase and by that based on Taq DNA polymerase, in the absence and presence of antibody to the respective DNA polymerases. Increased product DNA synthesis and higher sensitivity of detection were observed in the presence of antibody compared to those in the absence of antibody. 10- to 100- fold lower titer specimen of Influenza A virus and 10-fold lower titer specimen of Adeno virus could be detected in the presence of antibody than those detected in the absence of antibody to the appropriate DNA polymerase, in a PCR.
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PMID:Evaluation of PCR assays in presence of antibody to thermostable DNA polymerases for detection of microbial agents: avoiding false negative results for specimen containing low-titer agent. 967 Nov 76

Fifteen randomly selected nasopharyngeal (NP) swab specimens (culture-negative for influenza A virus) were spiked with influenza A virus and the nucleic acids were extracted and subjected to PCR amplification with Thermus aquaticus (Taq) and T. thermophilus (Tth) DNA polymerases. Products of the expected size, and giving equivalent band intensities, were obtained from four specimens with both polymerases. Fox six specimens, less products were obtained with Taq DNA polymerase than with Tth DNA polymerase. Products were detected from five NPs only by PCR with Tth DNA polymerase. The transport medium and the calcium alginate swab fibre of the specimens were shown not to be the source of the inhibitors. The incorporation of 32P-dCTP into cDNA, and the yield of PCR products of cDNA made from control RNA template (purified from H2O spiked virus suspension) were decreased in the presence of inhibitory extracts, showing that both the reverse transcription (RT) and PCR steps in amplification with Taq DNA polymerase were sensitive to the inhibitors. In contrast, Tth DNA polymerase was more resistant to the inhibitors and viral nucleic acid from all the specimens examined could be amplified and detected in a single step by RT-PCR with Tth DNA polymerase.
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PMID:Effect of inhibitors in clinical specimens on Taq and Tth DNA polymerase-based PCR amplification of influenza A virus. 985 50


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