Reverse transcription PCR (RT-PCR) is a technique used to detect and amplify RNA. It combines two steps: reverse transcription of RNA into complementary DNA (cDNA), followed by PCR amplification of the cDNA. This allows scientists to study gene expression and detect RNA viruses.
How RT-PCR Works
- RNA Extraction
Total RNA is extracted from the sample and treated with DNase to remove any contaminating genomic DNA. The RNA quality and concentration are checked before proceeding.
- Reverse Transcription
The RNA is mixed with reverse transcriptase enzyme, random primers or oligo-dT primers, and nucleotides. The reverse transcriptase uses the RNA as a template to synthesize a complementary DNA strand. The RNA template is then degraded by RNase H, leaving single-stranded cDNA.
- PCR Amplification
The cDNA is then used as the template for standard PCR with gene-specific primers. The PCR amplifies the cDNA, producing enough DNA to visualize on a gel or quantify by qPCR.
- Detection
The amplified PCR products are analyzed by agarose gel electrophoresis. The presence of a band at the expected size confirms that the target RNA was present in the original sample.
- Applications
RT-PCR is widely used to measure gene expression levels, detect RNA viruses such as HIV and SARS-CoV-2, validate RNA sequencing data, and analyze alternative splicing. When combined with qPCR, it becomes RT-qPCR, allowing real-time quantification of RNA.
