Fr-Fr 1-Step RT-PCR Master Mix is a 5X concentrated one-tube RT-PCR master mix that contains all necessary components for the reverse transcription (RT) and polymerase chain reaction (PCR) amplification of a specific target RNA from either total RNA or mRNA in a single tube. The proprietary 5X Reaction Master Mix contains an optimized buffer with reverse transcriptase, Taq DNA polymerase, dNTPs, Mg2+, and stabilizers. This system uses a mixture of an engineered fusion RT- RnaUsScript-20 RT, and DnaUs Hot Start Taq DNA polymerase in an optimized reaction buffer and can detect mRNA targets up to 2 kb. DnaUs Hot Start Taq DNA polymerase is an antibody-inactivated hot-start enzyme designed to block polymerase activity between ambient to RT reaction temperature. RnaUsScript-20 RT enzyme can synthesize cDNA at a temperature range of 40-55oC. Once the PCR step reaches denaturation temperature (94oC), Taq DNA polymerase activity is restored and the resulting PCR exhibits higher sensitivity, specificity and yield. The amount of input total RNA can range from 0.1 pg to 2 μg. Sufficient reagents are provided for 500 amplification reactions of 50 μl reaction volume each.