SuperScript® III Reverse Transcriptase: Evolution of the SuperScript® Reverse Transcriptases
SuperScript® III Reverse Transcriptase (RT) provides higher yields of full-length cDNA for more complete gene product representation compared to other RT enzymes. Robust cDNA synthesis is a critical component of gene expression research. Suboptimal RT reactions can lead to low yields of cDNA that compromise sensitivity or truncated cDNA that can lead to false negative results. Most reverse transcription enzymes fail to consistently produce cDNA with full representation of input RNA due to significant RNase H activity and limited thermostability. SuperScript® III RT has been engineered for higher thermostability and a longer half-life at 50°C. In addition SuperScript® III exhibits reduced RNase H activity. If you need maximum sensitivity for real time RT-PCR and microarray experiments and cDNA that represents input RNA with maximum fidelity, you need SuperScript® III RT.
Learn more about SuperScript® III RT
Engineered for Performance
With over thousands of references and citations, the SuperScript® reverse transcriptase (RT) family is a widely used brand of enzyme for cDNA synthesis. This brand of reverse transcriptase is designed to reliably deliver high yields of full-length cDNA. To meet a growing need for sensitivity, SuperScript® III RT has been engineered for a higher level of thermostability and a longer shelf life at 50°C.
Figure 1. Performance-based evolution of SuperScript® III reverse transcriptase. SuperScript® III RT was developed to provide maximum sensitivity for real-time RT-PCR, microarray experiments, and other gene expression applications.
Importance of RNase H
In addition to polymerase activity, reverse transcriptase possesses RNase H activity that degrades RNA in RNA/DNA hybrids; unfortunately, this is detrimental to the synthesis of cDNA from mRNA in vitro. In addition, RNase H activity diminishes the yield and size of cDNA by hydrolyzing the RNA template as polymerization proceeds.
Eliminating RNase H activity results in increased yields of full-length cDNA. SuperScript® III RT has mutations that knock out the RNase H activity. The ability of SuperScript® III to amplify cDNA from 353 bp to 12.3 kb is demonstrated in Figure 2.
Figure 2. SuperScript® III RT increases yields of full-length cDNA. SuperScript III RT was used to amplify 353 bp to 12.3 kb cDNA. The larger amplicons require 1 µg of RNA, likely due to the low abundance of full-length RNA and the difficulty in reading through a long transcript.
Effects of Temperature on cDNA Synthesis
RNA transcripts exhibit significant secondary structure that must be denatured for efficient reverse transcription. At higher temperatures, RNA is less structured, but common reverse transcriptases (e.g., MuLV and AMV) are also inactive at temperatures greater than 45°C. SuperScript® III RT has been engineered for high thermostability and has a half-life of 220 minutes at 50°C. This increases its ability to process RNA with secondary structures (Figure 3)
Half-life (min) at 50o C
Figure 3. (above) Thermostability of SuperScript® III RT. SuperScript® III RT is significantly more thermostable than MMLV or SuperScript® II RT. For example, at 55°C, MMLV and SuperScript® II RT are both inactive after 5 min, while SuperScript® III RT is still 80% active after 10 min.
Figure 4. (below) shows that both MMLV and SuperScript® II RT have difficulty generating cDNA as temperature increases. However, SuperScript® III RT is active at 55°C and is able to generate the highest yields of full-length cDNA, e.g., a 9.5 kb fragment.
RNA Detection Sensitivity
The ideal reverse transcriptase will reverse transcribe even the least abundant mRNA within a pool, allowing single-cell transcript detection. The high sensitivity of SuperScript® III RT is demonstrated with targets of varying sizes (Figure 5).
Figure 5. The high sensitivity of SuperScript® III RT. (A) SuperScript® III RT can easily achieve a signal with 0.1 pg input of transcripts, e.g.,β-actin 354 and glyceraldehye-3-phosphate dehydrogenase (GAPDH). (B) In addition, SuperScript® III RT is also capable of creating cDNA for PCR amplification from a single HeLa cell.
SuperScript® III vs. the Competition
The data shown above support the use of SuperScript® III reverse transcriptase as a high-quality reverse transcriptase for gene expression analysis, but how does it fare against the competition? We ran a head-to-head comparison with a popular reverse transcriptase and found that SuperScript® III RT delivers increased cDNA yields, has higher sensitivity, and generates more full-length transcripts than the competitior’s enzyme (Figure 6). Independent data1 have also shown SuperScript® III RT to give a higher yield of full-length cDNA compared to several commercially available reverse transcriptases.
Figure 6. Compared to a competitor’s reverse transcriptase, SuperScript III Reverse Transcriptase produces more full-length cDNA and more representative cDNA from endpoint RT-PCR.
Products Containing SuperScript® III Reverse Transcriptase
cDNA Synthesis direct from cells
End-point cDNA Synthesis