I. Removal of genomic DNA from RNA preparations
1. The reaction system is formulated as follows:

2. Incubate at 37 °C for 10 min.
3. Add 1 μL 50 mM EDTA and incubate at 65 °C for 10 min. RNA hydrolyzes during heating with divalent cations in the absence of a chelating agent.
4. Use the prepared RNA as a template for reverse transcriptase.
II. First Strand cDNA Synthesis
1. Set up the reverse transcription reaction according to the following table
2. Optional. If the RNA template is GC-rich or contains secondary structures, mix gently, centrifuge briefly and incubate at 65 °C for 5 min. Chill on ice, spin down and place the vial back on ice.
3. Add the following components in the indicated order:

4. Mix gently (gently with a pipette or gently with a vortex mixer at the lowest speed), then centrifuge the precipitated liquid.
5. If Oligo(dT)18 or gene-specific primers are used, incubate at 42℃ for 10-60min. If random hexamer(random hexamer) is used as primer, incubate at 25℃ for 10min, and then incubate at 42℃ for 10-60min. Reverse transcription of cDNA below 3kb can be done for 10min, reverse transcription of 3-6kb cDNA can be done for 30min, and reverse transcription of cDNA above 6kb is recommended for 60min. When random hexamer(random hexamer) is used as primer and subsequently used for qPCR, 10min is sufficient for subsequent detection of genes of any length.
6. Terminate the reaction by heating at 70°C for 5min. The reverse transcription reaction product can be directly used in PCR applications or stored at -20°C for less than one week. For longer storage, -70°C is recommended.
III. PCR Amplification of First Strand cDNA
The product of the first strand cDNA synthesis can be used directly in PCR or qPCR. The volume of first strand cDNA synthesis reaction mixture should not comprise more than 1/10 of the total PCR reaction volume. Normally, 2 μL of the first strand cDNA synthesis reaction mixture is used as template for subsequent PCR in 50 μL total volume.

1. Use DEPC to dispose of all equipment used in the study, or purchase equipment that has been proved to be nucleic acid-free. Wear gloves during the study and change them frequently to avoid RNA enzyme contamination.

2. Ensure that there is no RNA enzyme contamination in the reagents used.

3. Keep the kit tightly sealed. During the reverse transcription process, all tubes must be securely fastened.

4. Purified RNA must be free of salt, metal ions, ethanol and phenol, which will interfere with the first strand cDNA synthesis reaction. Trace contaminants can be removed by precipitation of RNA with ethanol.

5. In order to ensure the effective retrotranscriptional reaction, high-quality RNA templates need to be used.

6. When the template content is low or the subsequent PCR amplification fragment is too long, the reverse transcription time can be appropriately extended.