- Reverse transcriptase (RT) is an RNA-dependent DNA polymerase that catalyzes the synthesis of complementary DNA (cDNA) from an RNA template. Originally discovered in retroviruses such as HIV (Human Immunodeficiency Virus) and Murine Leukemia Virus (MLV), reverse transcriptase plays a central role in the retroviral life cycle, enabling integration of viral genetic material into the host genome.
- Biochemically, reverse transcriptases possess two key enzymatic activities: (1) polymerase activity, which synthesizes DNA from an RNA (or DNA) template, and (2) RNase H activity, which degrades the RNA strand of RNA-DNA hybrids. Some engineered reverse transcriptases used in molecular biology are modified to reduce or eliminate RNase H activity to enhance the stability of the RNA template during cDNA synthesis.
- Reverse transcriptase has become an essential tool in molecular biology and biotechnology, particularly in reverse transcription PCR (RT-PCR) and quantitative real-time PCR (RT-qPCR) for gene expression analysis. It is also fundamental for the generation of cDNA libraries, RNA virus detection, and single-cell transcriptomics. Popular laboratory variants include Moloney Murine Leukemia Virus (M-MLV) RT, Avian Myeloblastosis Virus (AMV) RT, and SuperScript RTs, which are engineered for improved thermostability and fidelity.
- Because reverse transcriptase lacks intrinsic proofreading ability (3′→5′ exonuclease activity), its fidelity is relatively low compared to DNA polymerases. However, modified versions with enhanced stability and improved processivity have been developed to address this limitation in research and diagnostic applications.
- In summary, reverse transcriptase is a versatile enzyme that underpins many RNA-to-DNA conversion technologies. It is crucial for exploring gene expression, understanding retroviral replication, and enabling RNA-based diagnostics and therapeutics.
