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View additional product information for SuperScript™ II Reverse Transcriptase - FAQs (18064071, 18064022, 18064014)
15 product FAQs found
If amplification products are generated in the control tube/well that contains no reverse transcriptase (i.e., the no-RT control), it may be necessary to eliminate residual genomic DNA from the RNA sample. Use the following protocol to remove genomic DNA from the total RNA preparation.Random primers are the best choice for degraded RNA, RNA with heavy secondary structure, non-polyadenylated RNA, or prokaryotic RNA. It is recommended only for two-step RT-PCR, and typically gives the highest yields, although the cDNA may not necessarily be full length. Oligo(dT) primers are good to use when trying to recover full-length cDNA from 2-step RT-PCR. The reaction is influenced by secondary structure and RNA quality. Gene specific primers should be used for very specific, mainly one-step RT-PCR reactions.
Random primers are the best choice for degraded RNA, RNA with heavy secondary structure, non-polyadenylated RNA, or prokaryotic RNA. It is recommended only for two-step RT-PCR, and typically gives the highest yields, although the cDNA may not necessarily be full length. Oligo(dT) primers are good to use when trying to recover full-length cDNA from 2-step RT-PCR. The reaction is influenced by secondary structure and RNA quality. Gene specific primers should be used for very specific, mainly one-step RT-PCR reactions.
Add the following to an autoclaved 0.5 mL microcentrifuge tube on ice:
1.Total RNA, ideally, less than or equal to 1 µg. (See Note 1 below.)
2.1.0 µL of 10X DNase buffer (200 mM Tris, pH 8.3, 500 mM KCl, 20 mM MgCl2).
3.0.1 U-3.0 U of DNase I (RNase-free, Cat. No. 18047019) or 1.0 U Dnase I, Amplification Grade (Cat. No. 18068015. (See Note 2 below.)
4.Bring volume up to 10 µL with DEPC-treated water.
5.Incubate at room temperature for 15 min. (See Note 3 below.)
6.Terminate the reaction by adding 1 µL 25 mM EDTA and heat 10 min at 65 degrees C. (See Note 4 below.)
7.Place on ice for 1 minute.
8.Collect by brief centrifugation. This mixture can be used directly for reverse transcription.
Please note the following:
1.To work with higher quantities of RNA, scale up the entire reaction linearly. Do not exceed 2 µg RNA in the 10 µL reaction. More RNA will increase the viscosity of the solution and prevent the DNAse I from diffusing and finding the DNA.
2.DNAse I, Amplification Grade has been extensively purified to remove trace ribonuclease activities commonly associated with other "RNAse-free" enzyme preparations and does not require the addition of placental RNAse inhibitor.
3.It is important not to exceed the 15 minute incubation time or the room temperature incubation. Higher temperatures and longer times could lead to Mg2+-dependent hydrolysis of the RNA.
4.This procedure requires careful pipetting of all solutions so that the concentration of divalent metal cation (Mg2+) is controlled.
5.Because the DNAse I must be heated to 65 degrees C to inactivate the enzyme, the concentration of free divalent metal ions must be low enough (less than 1 mM) after addition of the EDTA to prevent chemical hydrolysis of the RNA. See references below.
After the addition of EDTA, there is an approximately 1:1 molar ratio of Mg2+ :EDTA. EDTA chelates Mg2+ molecules on a 1:1 molar basis. Therefore, this RNA can be directly used in a reverse transcription reaction. First-strand reverse transcription buffers typically result in a final concentration of 2.5 mM Mg2+. If the reverse transcription buffer does not contain MgCl2, add it to the reaction at a final concentration of 2.5 mM. This results in a net final concentration of approximately 2.25 to 2.5 mM MgCl2.
References on RNA hydrolysis:
Molekulyarnaya Biologiya (1987) 21:1235-1241.
References on the mechanism of hydrolysis by other cations:
Eichorn GL and Butzov JY (1965) Biopolymers 3:79.
Butzov JY and Eichorn GL (1965) Biopolymers 3:95.
Farkas WR (1968) Biochim Biophys Acta 155:401.
The authors of the first paper express the opinion that the mechanism of the nonspecific hydrolysis by cations which proceeds through 2',3' cyclic phosphate formation is similar to that of specific hydrolysis such as RNA splicing.
The amount of RNA template for a cDNA synthesis is highly flexible and depends upon the amount of sample available and an individual's need. In general, 1 µg total RNA is used in a typical 20-µL RT reaction.
Find additional tips, troubleshooting help, and resources within ourReverse Transcription and RACE Support Center.
Some feel that the RNA in the RNA:DNA duplex after reverse transcription will inhibit PCR primers from annealing and amplifying the cDNA. The RNA is still present when using RNase H-mutant RTs. RNase H frees the cDNA from the RNA. On the other hand, some feel that the 95 degrees C denaturing step will cause the RNA primers to fall off the DNA and therefore RNase H treatment is not necessary. Therefore, this step is optional. For cloning of larger fragments, RNase H treatment can be beneficial.
This depends highly on the quality of the sample. mRNA itself makes up 1-5% of total RNA. Depending on the primer and enzyme used, reverse transcription can covert >70% of that into cDNA.
Find additional tips, troubleshooting help, and resources within our Reverse Transcription and RACE Support Center.
Random primers are the best choice for degraded RNA, RNA with heavy secondary structure, non-polyadenylated RNA, or prokaryotic RNA. It is recommended only for two-step RT-PCR, and typically gives the highest yields, although the cDNA may not necessarily be full length. Oligo(dT) primers are good to use when trying to recover full-length cDNA from 2-step RT-PCR. The reaction is influenced by secondary structure and RNA quality. Gene specific primers should be used for very specific, mainly one-step RT-PCR reactions.
Find additional tips, troubleshooting help, and resources within our Reverse Transcription and RACE Support Center.
No, the DTT will need to be replaced.
These enzymes contain the domains of RNase H, but they have been mutated. In RNase H activity detection assays, we are not able to detect any RNase H activity.
While the volume is dependent on the starting amount of RNA used for the first-strand synthesis and the abundance of the target gene, we'd recommend starting with 10% of the first-strand reaction for your PCR reaction.
We have not tested incorporation of biotin labeled nucleotides directly. Biotin should work as long as it is not substituted directly for its nucleotide replacement. Usually the biotin will be attached to one nucleotide such as TTP. We suggest that you try a reaction with a 1:1, 1:4, 1:10, and 1:50 replacement of the TTP in the reaction with biotin-labeled TTP. Most likely the 1:4 or 1:10 will work well. Having an excess of normal nucleotide around should space out the incorporation of biotin. This suggestion is speculative and has not been tested experimentally.
The following reagents will inhibit SuperScript II RT activity by at least 50%.
34% glycerol
4 µg/mL heparin
0.0025% (w/v) SDS
5% (v/v) formamide
17.0% (v/v) DMSO
4 mg/mL glycogen
30 mM guanidine-HCl
15 mM guanidine isothiocyanate
1 mM EDTA
2.5 mM NaPPi
0.4 mM Spermidine
The optimal temperature for SuperScript III RT is 50 degrees C, and can be used up to 55 degrees C. For some qRT-PCR reactions where gene-specific primers are used, you can do the RT reaction at 60 degrees C. The optimal temperature for SuperScript II RT is 42 degrees C, and can be used up to 50 degrees C. Optimal temperature for MMLV is 42 degrees C. ThermoScript RT shows optimal activity at 60 degrees C, and can be used at temperatures as high as 70 degrees C (for amplicons expected to be 1 kb or less). For PCR products expected to be greater than 1 kb, a maximum first strand synthesis temperature of 60-65 degrees C is suggested. Be sure your first-strand primer anneals at the high temperature, especially when gene-specific primers are used for high-temperature stable reverse transcriptases. We recommend oligo (dT)20 for cDNA synthesis when using an oligo (dT) primer for first-strand synthesis with these enzymes.
Include a control reaction where the RNA has not been incubated with reverse transcriptase to test for specificity. If this RNA gives a PCR product, it is most likely generated from genomic DNA contamination. Alternatively, a primer set spanning two different exons can be designed such that the PCR product from the cDNA would be of a different size compared to a product generated from genomic DNA. Primers may also be designed to span an exon/exon junctions. These primers are not likely to amplify from genomic DNA templates. For DNase treatment of RNA, we recommend using Amplification-Grade DNase I, Cat. No. 18068-015, or an equivalent product.
It is not always necessary to digest the first-strand cDNA with RNase H. For many primer-template combinations, PCR products are seen without the RNase H treatment. Since SuperScript II and III RT lack RNase H and ThermoScript RT essentially is RNase H minus, the un-nicked RNA/cDNA hybrids may not denature well during the initial denaturation steps in PCR, leading to decreased sensitivity of the PCR reaction. These cDNA templates may require RNase H digestion. If a PCR product is not obtained when an RNase H step is not included after cDNA synthesis, always repeat the PCR after an RNase H treatment.
Yes, you can use a DNA-RNA hybrid as a template for M-MLV Reverse Transcriptase.
We have not tested this for SuperScript reverse transcriptases, so we cannot guarantee it would also work with those products.
This article can be used as a reference for additional information.
Find additional tips, troubleshooting help, and resources within our Reverse Transcription and RACE Support Center.
SuperScript II Reverse Transcriptase and SuperScript First-Strand Synthesis System for RT-PCR are shipped on wet ice. Our packaging and gel ice are designed to last approximately 48 hours before rising above 8 degrees C. Overnight incubation under these shipping conditions does not affect the SuperScript II Reverse Transcriptase enzyme's activity, performance, or applicable expiry date.
Find additional tips, troubleshooting help, and resources within our Reverse Transcription and RACE Support Center.