Dataset Information

3'-Protected 2'-deoxynucleoside 5'-triphosphates as a tool for heat-triggered activation of polymerase chain reaction.

ABSTRACT: A new approach that improves the efficiency and specificity of polymerase chain reaction (PCR) has been developed. Heat-sensitive 3'-protected derivatives of 2'-deoxyribonucleoside 5'-triphosphates (dNTPs) have been synthesized and used as substitutes for natural dTTP, dCTP, dATP, and dGTP in PCR. Since 3'-protected dNTPs are either nonsubstrates or terminating substrates for Taq DNA polymerase, they do not support primer extension/elongation at low stringency conditions during PCR sample preparation when PCR artifacts such as primer dimers and mispriming products can form. At the initial heat-denaturing step and during the PCR sequence, the 3'-protecting group is cleaved, releasing 3'-unprotected dNTP that is a natural substrate for DNA polymerase. As a result, the primer extension/elongation proceeds only at an elevated temperature of PCR, when the interaction of primers and template is highly stringent and specific. Several 3'-protecting groups covering a wide range of deprotection kinetics have been tested. The 3'-O-tetrahydrofuranyl derivatives of dNTPs have demonstrated the best properties leading to a drastically reduced accumulation of PCR artifacts, such as "primer dimers" and "mispriming" products. Overall, PCR with 3'-THF-protected dNTPs demonstrated substantially improved performance and was more efficient and specific compared to PCR with standard dNTPs.

SUBMITTER: Koukhareva I

PROVIDER: S-EPMC2712722 | biostudies-literature | 2009 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

3'-Protected 2'-deoxynucleoside 5'-triphosphates as a tool for heat-triggered activation of polymerase chain reaction.

Koukhareva Inna I Lebedev Alexandre A

Analytical chemistry 20090601 12

A new approach that improves the efficiency and specificity of polymerase chain reaction (PCR) has been developed. Heat-sensitive 3'-protected derivatives of 2'-deoxyribonucleoside 5'-triphosphates (dNTPs) have been synthesized and used as substitutes for natural dTTP, dCTP, dATP, and dGTP in PCR. Since 3'-protected dNTPs are either nonsubstrates or terminating substrates for Taq DNA polymerase, they do not support primer extension/elongation at low stringency conditions during PCR sample prepar ...[more]

PMID: 19438248

Similar Datasets

Project description:The coformulation of the nucleos(t)ide analogs (NA) tenofovir (TFV) disoproxil fumarate (TDF) and emtricitabine (FTC) is approved for HIV-infection treatment and prevention. Plasma TFV and FTC undergo complicated hybrid processes to form, accumulate, and retain as their active intracellular anabolites: TFV-diphosphate (TFV-DP) and FTC-triphosphate (FTC-TP). Such complexities manifest in nonlinear intracellular pharmacokinetics (PK). In target cells, TFV-DP/FTC-TP compete with endogenous deoxynucleoside triphosphates (dNTP) at the active site of HIV reverse transcriptase, underscoring the importance of analog:dNTP ratios for antiviral efficacy. However, NA such as TFV and FTC have the potential to disturb the dNTP pool, which could augment or reduce their efficacies. We conducted a pharmacokinetics-pharmacodynamics (PKPD) study among forty subjects receiving daily TDF/FTC (300 mg/200 mg) from the first-dose to pharmacological intracellular steady-state (30 days). TFV/FTC in plasma, TFV-DP/FTC-TP and dNTPs in peripheral blood mononuclear cells (PBMC) were quantified using validated LC/MS/MS methodologies. Concentration-time data were analyzed using nonlinear mixed effects modeling (NONMEM). Formations and the accumulation of intracellular TFV-DP/FTC-TP was driven by plasma TFV/FTC, which was described by a hybrid of first-order formation and saturation. An indirect response link model described the interplay between TFV-DP/FTC-TP and the dNTP pool change. The EC50 (interindividual variability, (%CV)) of TFV-DP and FTC-TP on the inhibition of deoxyadenosine triphosphate (dATP) and deoxycytidine triphosphate (dCTP) production were 1020 fmol/106 cells (130%) and 44.4 pmol/106 cells (82.5%), resulting in (90% prediction interval) 11% (0.45%, 53%) and 14% (2.6%, 35%) reductions. Model simulations of analog:dNTP molar ratios using IPERGAY dosing suggested that FTC significantly contributes to the protective effect of preexposure prophylaxis (PrEP). Simulation-based intracellular operational multiple dosing half-lives of TFV-DP and FTC-TP were 6.7 days and 33 hours. This model described the formation of intracellular TFV-DP/FTC-TP and the interaction with dNTPs, and can be used to simulate analog:dNTP time course for various dosing strategies.

Project description:BackgroundChoosing appropriate primers is probably the single most important factor affecting the polymerase chain reaction (PCR). Specific amplification of the intended target requires that primers do not have matches to other targets in certain orientations and within certain distances that allow undesired amplification. The process of designing specific primers typically involves two stages. First, the primers flanking regions of interest are generated either manually or using software tools; then they are searched against an appropriate nucleotide sequence database using tools such as BLAST to examine the potential targets. However, the latter is not an easy process as one needs to examine many details between primers and targets, such as the number and the positions of matched bases, the primer orientations and distance between forward and reverse primers. The complexity of such analysis usually makes this a time-consuming and very difficult task for users, especially when the primers have a large number of hits. Furthermore, although the BLAST program has been widely used for primer target detection, it is in fact not an ideal tool for this purpose as BLAST is a local alignment algorithm and does not necessarily return complete match information over the entire primer range.ResultsWe present a new software tool called Primer-BLAST to alleviate the difficulty in designing target-specific primers. This tool combines BLAST with a global alignment algorithm to ensure a full primer-target alignment and is sensitive enough to detect targets that have a significant number of mismatches to primers. Primer-BLAST allows users to design new target-specific primers in one step as well as to check the specificity of pre-existing primers. Primer-BLAST also supports placing primers based on exon/intron locations and excluding single nucleotide polymorphism (SNP) sites in primers.ConclusionsWe describe a robust and fully implemented general purpose primer design tool that designs target-specific PCR primers. Primer-BLAST offers flexible options to adjust the specificity threshold and other primer properties. This tool is publicly available at http://www.ncbi.nlm.nih.gov/tools/primer-blast.

Project description:Background and aimDifferent polymerase chain reaction (PCR) techniques have and are still being used for the direct detection of Brucella DNA in serum samples of different animal species and humans without being validated or properly validated, resulting in discrepancies. Thus, this study aimed to evaluate the diagnostic performance of the TaqMan Real-Time-PCR (RT-PCR) targeting the bcsp31 gene versus conventional PCR for the accurate diagnosis of brucellosis at the genus level in cattle sera.Materials and methodsOne hundred and eighty-four serum samples were collected from bacteriologically positive and negative cows with ages ranging from 1 to 5 years old at some infected private farms in the Nile Delta under quarantine measures as well as brucellosis free farms. These samples were classified into four groups after serological diagnosis and investigated by TaqMan RT-PCR and conventional PCR targeting the IS711 gene for Brucella DNA detection. The diagnostic performance characteristics of both PCR techniques were estimated considering the bacteriological results as a gold standard.ResultsTaqMan RT-PCR revealed superiority over conventional PCR; it was able to detect Brucella DNA in 95% (67/70) and 89% (25/28) of the cattle sera samples belonging to Group 1 (serologically and bacteriologically positive) and Group 2 (serologically negative but bacteriologically positive), respectively. On evaluating the diagnostic performance, TaqMan RT-PCR showed superior diagnostic sensitivity (93.9%), diagnostic specificity (88.4%), performance index (182.3), almost perfect kappa agreement (0.825±0.042), strong positive correlation (r=0.826), high accuracy based on the receiver operating characteristic (ROC) curve, and area under the ROC curve (0.911) at p<0.05 and CI of 95%.ConclusionA cattle serum sample is not the metric of choice for targeting Brucella genomic DNA by conventional PCR. The time-saving and rapid TaqMan RT-PCR method revealed a better diagnostic performance in the detection of Brucella DNA in cattle sera. Such performance offered by TaqMan RT-PCR may be considered a step toward the possibility of using such technology in the direct differentiation between Brucella-infected and -vaccinated cattle immunized by smooth vaccines from cattle sera using primers specific for such vaccines.

Dataset Information

3'-Protected 2'-deoxynucleoside 5'-triphosphates as a tool for heat-triggered activation of polymerase chain reaction.

Publications

3'-Protected 2'-deoxynucleoside 5'-triphosphates as a tool for heat-triggered activation of polymerase chain reaction.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets