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SuperScript™ II Reverse Transcriptase, 2,000 Units - FAQs

View additional product information for SuperScript™ II Reverse Transcriptase - FAQs (18064071, 18064022, 18064014)

12 product FAQs found

How can I remove genomic DNA contamination from my sample prior to performing RT-PCR?

We recommend using ezDNase (Cat. No. 11766051). ezDNase Enzyme's high specificity for double-stranded DNA enables efficient and fast genomic DNA removal without reduction in the quality or quantity of RNA. ezDNase Enzyme is heat-labile and so can be easily deactivated by heat treatment at moderate temperature (55 degrees C). These features make ezDNase Enzyme an excellent choice for genomic DNA removal prior to reverse transcription reactions.

How much RNA should be employed for first-strand cDNA synthesis?

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.

Should I treat the cDNA with RNase H prior to downstream processing?

RNase H treatment is not always necessary. Many PCR reactions work without it. However, for cDNA synthesized with RNase H-deficient reverse transcriptases (like SuperScript II, III, and IV), RNA/cDNA hybrids—especially GC-rich ones—may not denature well, reducing PCR sensitivity. RNase H treatment can help in such cases. Additionally, RNase H treatment is beneficial for cloning larger fragments.

What percentage of RNA is converted to cDNA when performing reverse transcription?

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.

I'm setting up my RT reaction and am trying to decide whether I should use random primers, oligo(dT) primer, gene-specific primer, or oligo(dT)/random mix primers. What would you suggest?

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.

The DTT in my reverse transcription kit has precipitated—can I still use it?

No, the DTT will need to be replaced.

Are SuperScript II and III RTs RNase H minus?

These enzymes contain the domains of RNase H, but they have been mutated for reduced RNase H activity. In RNase H activity detection assays, we are not able to detect any RNase H activity.

How much of the first-strand cDNA reaction should I load for PCR?

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.

What reagents inhibit SuperScript II RT activity?

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

What is the highest temperature that MMLV, SuperScript II, SuperScript III, or SuperScript IV RTs can be used?

The optimal temperature for for MMLV is 42 degrees C. The optimal temperature for SuperScript II RT is 42 degrees C, and can be used up to 50 degrees C. 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 IV RT is 50 degrees C, but can be used up to 65 degrees C.

How can I tell if my RT-PCR product is RNA specific?

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 ezDNase Enzyme (Cat. No. 11766051).

What is the shipping condition for SuperScript II Reverse Transcriptase and SuperScript First-Strand Synthesis System for RT-PCR?

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.