|
|
||||||||
Articles |
1
Institut für Biochemie, FB 08, Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany.
a Author for correspondence. Fax 49-641-9935409; e-mail Meinhard.U.Hahn{at}chemie.bio.uni-giessen.de
Background: Quantitative real-time PCR is increasingly used to quantify copy numbers of nucleic acids for clinical applications. We observed that the measurements of allele imbalances of the tumor suppressor gene p16 and the oncogene ErbB-2 yielded results with variable precision under certain experimental conditions.
Methods: We used the LightCyclerTM real-time PCR system to quantify different genomic target sequences using hybridization probes or SYBR Green for detection.
Results: With two primer/template systems (p16 and ErbB-2), we observed sinusoidal scattering of the threshold cycle values depending on the capillary position in the thermostated reaction chamber. This scattering depended on the denaturation temperature only when complete genomic DNA was used as template and did not occur when PCR product or restricted or boiled genomic DNA was used or the denaturation temperature in the first cycles was increased (and other targets, such as p53, HBB, IGF-1, GAPDH, and PBGD, did not show this behavior).
Conclusions: Before a primer system is used for precise quantitative real-time PCR, the dependence of the quantification results on the positions of reaction tubes in the thermocycler should be tested. Our data indicate that amplification efficiencies, especially in the first cycles, depend not only on the priming efficiencies of the primers and the melting temperature of the amplicon, but also on the melting behavior of the amplicons genomic vicinity. Complete denaturation of genomic DNA is necessary to maximize precision of quantitative PCR. Higher denaturation temperatures in the initial cycles or boiling of DNA before the PCR can improve the accuracy of quantification in some cases.
The following articles in journals at HighWire Press have cited this article:
![]() |
K. S. Harve, R. Lareu, R. Rajagopalan, and M. Raghunath Understanding how the crowded interior of cells stabilizes DNA/DNA and DNA/RNA hybrids-in silico predictions and in vitro evidence Nucleic Acids Res., October 23, 2009; (2009) gkp884v1. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. Lyon and C. T. Wittwer LightCycler Technology in Molecular Diagnostics J. Mol. Diagn., March 1, 2009; 11(2): 93 - 101. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. von Kanel, F. Adolf, M. Schneider, J. Sanz, and S. Gallati Sample Number and Denaturation Time Are Crucial for the Accuracy of Capillary-Based LightCyclers Clin. Chem., July 1, 2007; 53(7): 1392 - 1394. [Full Text] [PDF] |
||||
![]() |
R. Kindich, A. R. Florl, V. Jung, R. Engers, M. Muller, W. A. Schulz, and B. Wullich Application of a Modified Real-Time PCR Technique for Relative Gene Copy Number Quantification to the Determination of the Relationship between NKX3.1 Loss and MYC Gain in Prostate Cancer Clin. Chem., March 1, 2005; 51(3): 649 - 652. [Full Text] [PDF] |
||||
![]() |
D. De Medici, L. Croci, E. Delibato, S. Di Pasquale, E. Filetici, and L. Toti Evaluation of DNA Extraction Methods for Use in Combination with SYBR Green I Real-Time PCR To Detect Salmonella enterica Serotype Enteritidis in Poultry Appl. Envir. Microbiol., June 1, 2003; 69(6): 3456 - 3461. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Wilhelm, A. Pingoud, and M. Hahn Real-time PCR-based method for the estimation of genome sizes Nucleic Acids Res., May 15, 2003; 31(10): e56 - e56. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Konigshoff, J. Wilhelm, R. M. Bohle, A. Pingoud, and M. Hahn HER-2/neu Gene Copy Number Quantified by Real-Time PCR: Comparison of Gene Amplification, Heterozygosity, and Immunohistochemical Status in Breast Cancer Tissue Clin. Chem., February 1, 2003; 49(2): 219 - 229. [Abstract] [Full Text] [PDF] |
||||
![]() |
I. M. Mackay, K. E. Arden, and A. Nitsche Real-time PCR in virology Nucleic Acids Res., March 15, 2002; 30(6): 1292 - 1305. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |