QuantiFast SYBR^® Green PCR Kit

Yes, please visit our website section 'Using endogenous control genes in real-time RT-PCR' for general information. It provides a list of relative gene expression levels for commonly used human and mouse reference genes.

We offer a set of ready-to-order control genes for use in SYBR Green based as well as probe based real-time RT-PCR.

• QuantiTect Primer Assays are primer sets for use in SYBR Green based real-time RT-PCR analysis.
• QuantiFast Probe Assays are primer-probe sets for use in dual-labeled probe based real-time RT-PCR.

In addition, you may want to refer to the following citations on reference gene selection for quantitative real-time PCR:

• Vandesompele J, De Preter K, Pattyn F, Poppe B, Van Roy N, DePaepe A, Speleman F [2002]: Accurate normalization of real-time quantitative RT-PCR data by geometric averaging of multiple internal control genes. Genome Biol 2002, 3:0034.

• Radonic A, Thulke S, Mackay IM, Landt O, Siegert W, Nitsche A., 2004. Guideline to reference gene selection for quantitative real-time PCR. Biochem Biophys Res Commun. 313(4): 856-62.

• Katrien Smits,Karen Goossens, Ann Van Soom, Jan Govaere, Maarten Hoogewijs, Emilie Vanhaesebrouck,Cesare Galli, Silvia Colleoni, Jo Vandesompele, and Luc Peelman [2009]Selection of reference genes for quantitative real-time PCR in equine in vivo and fresh and frozen-thawed in vitro blastocysts. BMC Res Notes. Dec 11;2:246.

This depends on the amount of contaminating amplicon. If the contamination is high (e.g., 10e6 copies), then there will still be traces of amplicon remaining. However, we expect a reduction by a factor of around 1000 using QuantiTect +UNG Kits (i.e., after UNG pretreatment, only 0.1% of the initial contamination will still be present in the reaction).

The reduced reaction volume recommended for QuantiFast PCR Kits compared to QuantiTect PCR Kits allows more efficient temperature transfer during short cycling steps.

Yes, the QuantiFast SYBR Green PCR Kit and QuantiFast Probe PCR Kits are available for 80 x 25 µl reactions. This trial-kit size is not available for QuantiFast RT-PCR Kits.

Replicates in real-time PCR may have different plateau heights due to differences in the reaction kinetics for each sample. Even though replicates start out with identical template amounts, the rate at which reagents are being depleted, and the point when exponential accumulation of PCR product stops and becomes linear, differ between replicates. This will result in different plateau heights, the stage where PCR reactions have come to a halt, and little or no additional PCR product is being amplified. You can find further information in Chapter 'Quantification of target amounts' of our Brochure "Critical Factors for Successful Real-Time PCR".

Yes. QuantiTect Primer Assays are guaranteed for use with QuantiFast SYBR Green PCR and QuantiFast SYBR Green RT-PCR Kits at the specified annealing temperature of 60ºC. We have extensively tested many QuantiTect Primer Assays with success under these conditions.

Any DNA contamination will artificially inflate the SYBR Green signal, yielding skewed gene expression profiles and false-positive signals. The most common source of DNA contamination is from PCR products generated during previous experiments. Such contamination is most often due to the improper disposal of tubes, tips, and gels that previously came into contact with PCR products. Additionally, PCR products may also contaminate pipettors, racks, work pads, and commonly used reagents such as water and buffers. To minimize the risk of contaminating your experiment with extraneous DNA, the following steps should be taken:

• Remove a single aliquot of water from your PCR-grade stock, sufficient to complete the experiment. This minimizes the number of times that the stock container is opened, thereby minimizing contamination risks.
• Use only fresh PCR-grade reagents and disposable labware.
• Treat any labware (tubes, tips, and tip boxes) used in PCR with 10% bleach, before discarding.
• Maintain a dedicated workspace for PCR setup (perhaps a PCR-only hood), away from areas of the lab where post-PCR work is done, such as running gels, enzyme digestions, and cloning.
• Change the lab bench pads/papers often and decontaminate lab benches and labware (racks, pipettors, etc.) before each use by washing with 10% bleach, and/or exposing to UV light for at least 10 minutes. This serves to degrade and/or inactivate contaminating DNA.
• Before, during, and after the experiment, minimize the opening and closing of any tubes or plates used during the experiment.  

Recombinant DNA (recDNA) is very stable and represents the average size of mRNA. Due to the cloning and purification processes, obtaining recDNA can lengthen the overall process of generating standards.

Recombinant RNA (recRNA) and native RNA undergo reverse transcription as well as PCR, and mimic the natural process for mRNA in RT-PCR. Complicated cloning and purification of recRNA and instability of recRNA are two disadvantages for using recRNA as a standard. For further details please refer to the section "Generating Standard Curves" in Appendix D of the QuantiTect SYBR Green PCR Handbook.

QuantiTect Primer Assays are primer pairs designed and bioinformatically validated specifically for real-time RT-PCR with SYBR Green detection. To find a primer assay for your target gene of interest, please visit our GeneGlobe data base.

For best results, we strongly recommend using QuantiTect Primer Assays in combination with QIAGEN's products for SYBR Green-based Real-Time PCR and RT-PCR.

Compared with QuantiTect Kits, the recommended reaction volume for QuantiFast Kits is reduced from 50 µl to 25 µl (96-well block cyclers), and from 20 µl to 10 µl (384-well block cyclers).

The volume of master mix remains the same, which means that QuantiFast Kits offer twice the number of reactions as QuantiTect Kits. However, for LightCycler instruments, the recommended reaction volume remains the same (20 µl).

No. UNG treatment does not provide any advantage for the QuantiFast and Rotor-Gene PCR kits because the mastermixes do not contain dUTP. Use the QuantiTect kits if you intend to use the UNG treatment.

The annealing temperature for QuantiTect Primer Assays should be 55^oC when used with the QuantiTect SYBR Green PCR Kit and the QuantiTect SYBR Green RT-PCR Kit.

Use of the QuantiFast SYBR Green PCR and QuantiFast SYBR Green RT-PCR Kits requires a combined annealing/extension step at 60^oC, as described in the QuantiTect Primer Assay Handbook.

Note that these Assays are guaranteed for use with the QuantiTect or QuantiFast chemistries only!

The high primer concentration (1 µM) required for the QuantiFast SYBR Green PCR Kits allows efficient hybridization during the shortened annealing time. This high concentration is well suited for both one-step and two-step RT-PCR.

The storage time for QuantiFast PCR Kits is shorter than for QuantiTect PCR Kits, because all QuantiFast master mixes contain HotStarTaq Plus DNA Polymerase, instead of HotStarTaq DNA Polymerase which requires longer activation times.

Excessive exposure to elevated temperatures will result in reactivation of the HotStarTaq Plus DNA Polymerase, eventually leading to nonspecific amplification.

If the extra peaks seem irregular or noisy, do not occur in all samples, and occur at temperatures less than 70 ºC, then these peaks may not represent real PCR products and instead may represent artifacts caused by instrument settings.

Usually extra peaks caused by secondary products are smooth and regular, occur reproducibly in most samples, and occur at temperatures greater than 70 ºC. Characterization of the product by agarose gel electrophoresis is the best way to distinguish between these cases. If only one band appears by agarose gel then the extra peaks in the dissociation curve are instrument artifacts and not real products. If this is the case, refer to the thermal cycler user manual, and confirm that all instrument settings (smooth factor, etc.) are set to their optimal values.

The REST 2009 (Relative Expression Software Tool) software applies mathematic models that compensate for the different PCR efficiencies of the gene of interest and reference genes. In addition, the software can use multiple reference gene normalization to improve the reliability of result, as well as provides statistical information suitable for robust comparison of expression in groups of treated and untreated. QIAGEN offers the REST 2009 software free of charge.

Yes, QuantiTect Primer Assays work very well under fast-cycling conditions. Results achieved with QuantiFast SYBR Green Kits are comparable to those achieved with QuantiTect SYBR Green Kits.

For each QuantiTect Primer Assay, we retrieve the sequence of the target gene from curated databases and exclude SNP regions from assay design.

We then use our proprietary algorithm to design assays that amplify RNA sequences only (i.e., at least one primer overlaps a splice site), provided that information on the position of splice sites is available. The assays are designed to provide optimal performance with QuantiFast and QuantiTect SYBR Green Kits.

After assay design, we validate randomly selected QuantiTect Primer Assays using real-time RT-PCR to check their compatibility with various real-time cyclers. Both two-step and one-step RT-PCR are carried out. Successful amplification of the target is indicated by the following factors: high sensitivity, high efficiency, high specificity (i.e., a single peak in melting curve analysis), and no primer–dimers in the no-template control (NTC).

To find a QuantiTect Primer Assay for your target gene of interest, please visit our GeneGlobe data base.

The QuantiFast SYBR Green PCR and QuantiFast Probe PCR Kits allow reliable detection down to 10 target copies. Detection of lower copy numbers down to single copy level may also be possible, however, it depends on the stochastics when working with highly diluted samples. Additional optimization of primer/probe design is usually required.

Check the template quality and integrity by amplifying an endogenous control gene. Check the amplicon by QIAxcel Advanced system or agarose gel electrophoresis to show that amplification was successful.

Determine whether the gene of interest is expressed in your sample. See How can I find out if my gene of interest is express in a specific tissue type or cell line.  Ensure the assay setup and cycling conditions are correct, and that the data collection channel matches the emission wavelength of the fluorescent dye used. Use a control sample in which the gene of interest is definitely expressed.

If the issue persists, please send the original run file to QIAGEN Technical Services.

Our unique multiplex PCR buffer system with ammonium and potassium ions and Factor MP has been further optimized in QuantiFast and Rotor-Gene Kits. We have also discovered Q-Bond, a buffer component which supports the rapid formation of the polymerase–primer–template complex, leading to reduced annealing times.

For duplex analysis, using non-fluorescent quenchers (e.g., Black Hole Quencher^®) is preferred over fluorescent quenchers (e.g., TAMRA fluorescent dye). For triplex and 4-plex analysis, QIAGEN strongly recommends using non-fluorescent quenchers. Generally, use the green channel, the yellow channel, and the orange and crimson channels to detect the least abundant target, the second least abundant target, and the two most abundant targets, respectively. For instrument-specific recommendations, please see the handbooks for the QuantiTect Multiplex PCR kit, QuantiFast Multiplex kit or Rotor-Gene Multiplex kit.

Assuming 100% amplification efficiency, each step increase in Ct value represents a doubling in the amount of qPCR template. Therefore, evaluating the difference in Ct values between the qPCR assay, and its matching NRT control, leads to the following predictions:

The gDNA wipeout buffer incubation step can be skipped when the total RNA is free from genomic DNA. However, the gDNA wipeout buffer is still required to be added because the reverse transcription step is optimized in the presence of components in the gDNA wipeout buffer.

Dissociation curves are carried out at the end of a PCR experiment by following a 3-step procedure.

First, all the components are denatured at 95°C, followed by complete annealing at a set temperature (based on the primer Tm values), followed by a gradual increase in temperature up to 95°C. Fluorescence intensity is monitored during this final temperature increase, resulting in the generation of a melting curve or dissociation curve.

By analyzing the first derivative of such a curve, you can readily assess the homogeneity of the PCR products, including the presence of primer–dimers, thereby determining the specificity of the PCR reaction. It is important to carry out such post-PCR analyses when using SYBR Green probe chemistry due to this reagent's lack of sequence specificity.

We highly recommend any QuantiTect or QuantiFast Kit for quantitative PCR on cDNA generated with the QuantiTect Whole Transcriptome Kit.

No. Optimized thermal cycling programs for use with QuantiFast Kits and a Program Selection Guide are available.

To install these programs on your Mastercycler ep realplex, contact your Eppendorf sales representative or visit our QIAGEN/Eppendorf Alliance page.

Depending on the qPCR instrument, time savings when switching from standard cycling (e.g., QuantiTect PCR Kits) to fast cycling using QuantiFast Kits range from 40% to 60%.

Reliable HRM analysis results depend on template quality, highly specific HRM PCR kit with a saturation dye, a real-time instrument with HRM capability, and powerful software package. Factors critical for successful HRM analysis are:

• Use the same genomic DNA purification procedure for all samples being analyzed by HRM. This avoids variation due to differing composition of elution buffers.
• DNA template concentrations should be normalized using the same dilution buffer. Ensure the C_T values are below 30 and differ no more than 3 C_T values across individual samples.
• Design assays with amplicon length 70–350 bp. For SNP analysis, use amplicon length 70–150 bp.
• Always start with 0.7 µM primer concentration

For more details, please refer to the HRM Technology – FAQs and the Critical Success Factor for HRM performance.

The Q-Bond Molecule, present in the PCR Buffer of the QIAGEN Fast Cycling PCR Kit and the QuantiFast Kits, dramatically increases the binding affinity of DNA polymerase to single-stranded DNA, thereby facilitating the reduction of annealing time to just a few seconds. It is a non-protein PCR component. Unfortunately, all further information on this molecule is proprietary.

The activation time for HotStarTaq Plus DNA Polymerase used in the QuantiFast SYBR Green PCR Kits is longer than that for QuantiFast Probe PCR Kits. This is due to differences in buffer composition. Buffer components such as salts and additives influence the time required for enzyme activation.

Shorter amplification products facilitate high PCR efficiencies. Ideally, amplicon length should be less than 150 bp for optimal amplification efficiency. PCR efficiencies close to 100% are a crucial prerequisite for accurate quantification of target copy numbers in real-time PCR.

For quantification of RNA, we strongly recommend using RNA molecules as standards. Use of in vitro transcripts as standards takes into account the variable efficiency of the RT reaction. An alternative to the use of in vitro transcripts as RNA standards is the use of a defined RNA preparation (e.g., from a cell line or virus preparation), for which the absolute concentration of the target has already been determined.

For quantification of DNA, several types of DNA can be used, such as plasmids, PCR products, or genomic DNA.

For more information, see Appendix E 'Generating Standard Curves' in the QuantiTect Probe PCR Handbook.

We have performed numerous tests comparing the performance of Rotor-Gene SYBR Green PCR Kits and QuantiTect Kits with QuantiTect Primer Assays. Due to the optimized ion concentrations in the PCR buffers, both perform equally well with QuantiTect Primer Assays and do not require any adjustment of primer concentration.

We recommend a reaction volume of 10 µl when using 384-well blocks with QuantiFast PCR Kits. If reducing the reaction volume to 2 µl, results will vary depending on the real-time cycler used.

Please contact QIAGEN Technical Services for more information.

This is due to differences in composition between PCR and RT-PCR buffers. QuantiFast PCR Buffers are optimized for fast amplification with shortest possible PCR steps, while QuantiFast RT-PCR Buffers are optimized for reverse transcription and subsequent amplification.

The Mastercycler ep realplex does not require ROX dye. You can use QuantiFast Probe PCR +ROX Vial Kits (no ROX dye in the master mix), QuantiFast SYBR Green PCR and QuantiFast SYBR Green RT-PCR Kits (ROX dye in the master mix does not interfere with real-time quantification).

Rotor-Gene Kits are specifically developed for the Rotor-Gene Q PCR Cycler. The unique rotary system of the cycler combined with the kits’ proprietary buffer system enable ultrafast cycling. Rotor-Gene Kits do not contain ROX dye since no normalization to a passive reference is required. Also, Rotor-Gene Kits do not contain dUTP; therefore, UNG pretreatment is not possible.

No. The master mix in QuantiFast PCR Kits contains only dTTP. To perform a UNG treatment, we recommend using QuantiTect Kits.

We have compared QuantiFast Kits and QuantiTect Kits using around 30 different assays (using both SYBR Green and Probe detection for each assay).

QuantiFast Kits gave identical or sometimes better Ct values than QuantiTect Kits (except for very long amplicons). Therefore, scientists switching from QuantiTect to QuantiFast Kits can, in most cases, obtain comparable results.

Depending on primer design and copy number of target, primer-dimer may occur and its signal might be detected. Typical strategies against this are to optimize PCR conditions and/or redesign the assay.

Alternatively, an additional data-acquisition step can be added to the 3-step cycling protocol. First, determine the melting temperatures (T_m) for both the amplicon and the primer-dimer. Then, add a 15 second data-acquisition step with a temperature that is higher than the primer-dimer T_m, but approximately 3ºC lower than the specific amplicon T_m.

The two-step cycling protocols of the QuantiFast SYBR Green PCR Kits allow a significant reduction in cycling time. It is more effective than reducing individual times for annealing and extension.

The master mix in QuantiFast SYBR Green Kits contains an optimized concentration of ROX dye that works well with all cyclers.

QuantiFast Probe PCR Kits are available in two formats:

• the QuantiFast Probe PCR Kit with master mix containing ROX dye
• the QuantiFast Probe PCR +ROX Vial Kit with master mix not containing ROX dye, and a separate vial of ROX dye

We recommend using the latter with the Applied Biosystems 7500 Fast System. Use the ROX concentration indicated in the QuantiFast Probe PCR Kits handbook.

We got comparable results on ABI 7500 and the ViiA7 with the standard protocol in the QuantiFast SYBR Green PCR kit.

If the extra peaks seem irregular or noisy, do not occur in all samples, and occur at temperatures less than 70 ºC, then these peaks may not represent real PCR products and instead may represent artifacts caused by instrument settings.

Usually extra peaks caused by secondary products are smooth and regular, occur reproducibly in most samples, and occur at temperatures greater than 70 ºC. Characterization of the product by agarose gel electrophoresis is the best way to distinguish between these cases. If only one band appears by agarose gel then the extra peaks in the dissociation curve are instrument artifacts and not real products. If this is the case, refer to the thermal cycler user manual, and confirm that all instrument settings (smooth factor, etc.) are set to their optimal values.