Reverse transcriptase (RT) is an enzyme used to generate complementary DNA (cDNA) from an RNA template, a process termed reverse transcription. RT is needed for the replication of retroviruses (e.g. HIV), and RT inhibitors are widely used as antiretroviral drugs. RT activity is also associated with the replication of chromosome ends (telomerase) and some mobile genetic elements (retrotransposons).
Retroviral RT has three sequential biochemical activities-- (a) RNA-dependent DNA polymerase, (b) ribonuclease H, and (c) DNA-dependent DNA polymerase. These activities are used by the retrovirus to convert single-stranded genomic RNA into double-stranded cDNA which can integrate into the host genome, potentially generating a long-term infection that can be very difficult to eradicate. The same sequence of reactions is widely used in the laboratory to convert RNA to DNA for use in molecular cloning, RNA sequencing, polymerase chain reaction (PCR), or genome analysis.
Well studied reverse transcriptases include:
- HIV-1 reverse transcriptase from human immunodeficiency virus type 1 (PDB 1HMV)
- M-MLV reverse transcriptase from the Moloney murine leukemia virus
- AMV reverse transcriptase from the avian myeloblastosis virus
- Telomerase reverse transcriptase that maintains the telomeres of eukaryotic chromosomes
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