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)

Synthesis of radiolabeled DNA probes via polymerase chain reaction (PCR) is a convenient alternative to the more conventional methods of random primer-labeling and nick translation. PCR requires less template and allows the synthesis of radiolabeled probes from specific sequences contained within cloning vectors and genomic DNA. Under nucleotide imbalance conditions where the concentration of the radiolabeled nucleotide was 0.825 microM and the other dNTPs were each > 25 microM, amplification by Taq DNA polymerase was inhibited. Reducing the concentrations of the unlabeled dNTPs resulted in greater yields of amplification product with maximal yield obtained when the concentration of three unlabeled nucleotides was two- to eightfold higher than that of the limiting labeled nucleotide. When we utilized this amplification method for synthesis of an 800-bp glyceraldehyde-3-phosphate (GAPDH) dehydrogenase probe, 87% of the added [32P]dCTP was incorporated into amplification product. Application of this method for synthesis of high specific activity probes ( > 4 x 10(9) cpm/micrograms) up to 2.6 kb in length is demonstrated and utility of the 800-bp GAPDH probe for hybridization to Northern blots for detection of GAPDH mRNA is presented.
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PMID:Nucleotide imbalance and polymerase chain reaction: effects on DNA amplification and synthesis of high specific activity radiolabeled DNA probes. 798 88

We have developed real-time PCR systems to quantitate feline cytokine gene expression. The method is based on the cleavage of fluorescent dye-labelled probes by the 5'-3' exonuclease activity of the Taq DNA polymerase during PCR and measurement of fluorescence intensity by a Sequence Detection System. The feline-specific TaqMan probes were designed to encompass an intron, thus allowing differentiation of complementary DNA versus genomic DNA amplification products. Quantitative analysis of cytokine cDNA concentrations was performed in comparison to feline GAPDH. Messenger RNA (mRNA) from the universally expressed housekeeping gene GAPDH proved to be useful as an amplification control and allowed for correction of variations in the efficiencies of RNA extraction and reverse transcription. GAPDH mRNAs were readily detectable in cDNAs prepared from unstimulated feline peripheral blood mononuclear cells (PBMCs) and from frozen cell pellets, while cytokines (Interleukin (IL)-4, IL-10, IL-12 p35, IL-12 p40, IFNgamma, IL-16) were expressed at variable amounts. IFNgamma transcription was found to be upregulated in stimulated PBMCs and feline cell lines. The synthesis of cDNA and the performance of the PCR in separate tubes proved to be of superior sensitivity compared to a single-tube based system. The assays described are highly reproducible, require no post-PCR manipulation of the amplicons and permit the analysis of several hundred PCR reactions per day. With this method it is possible to detect and quantify cytokine mRNA expression reliably in small amounts of cells even after storage of samples for at least 5 years.
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PMID:Quantitative real-time PCR for the measurement of feline cytokine mRNA. 1058 8

Single nucleotide instability (SNI), an increase in spontaneous point mutation rates (MRs) without involvement of microsatellite instability, is present in rat mammary carcinoma cell lines and human breast cancer cell lines. A:T to C:G transversions, which are generally rare, were frequently observed in two rat mammary carcinoma cell lines and in their primary carcinomas, and were considered to be related to the molecular mechanism of SNI. In this study, two known molecular mechanisms that cause increases of A:T to C:G transversions, inactivation of the MutT mammalian homologue (Mth1) gene and overexpression of the DNA polymerase k (Pol k) gene, were analyzed in two rat mammary carcinoma cell lines and 11 rat primary carcinomas. PCR-SSCP analysis revealed no mutations in the entire Mth1 coding region. Quantitative real-time RT-PCR analysis showed that Mth1 mRNA expression was slightly, but significantly, increased in the primary carcinomas (P = 0.001 using GAPDH for normalization, and P = 0.002 using histone H4, t-test), contrary to our expectation, and was decreased to 1 / 2 in the cell lines. The expression of Pol k, which is known to be error-prone with frequent A:T to C:G transversions, was rather decreased in the cell lines and primary carcinomas. Inactivation of Mth1 and overexpression of Pol k were unlikely to have caused SNI in the two rat mammary carcinoma cell lines with a high frequency of A:T to C:G transversions, and searching for other unknown molecular mechanisms is important.
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PMID:The absence of Mth1 inactivation and DNA polymerase kappa overexpression in rat mammary carcinomas with frequent A:T to C:G transversions. 1203 45