Reverse transcriptase



Reverse Transcriptase

3D model of HIV reverse transcriptase

Other names:Deoxynucleoside-triphosphate:
DNA deoxynucleotidyltransferase (RNA-directed)
  • RNA-directed DNA polymerase
  • DNA nucleotidyltransferase (RNA-directed)
  • Revertase
Database Links
EC number: 2.7.7.49

In DNA. Normal transcription involves the synthesis of RNA from DNA; hence, reverse transcription is the reverse of this.

Reverse transcriptase was discovered by Howard Temin at the University of Wisconsin-Madison, and independently by David Baltimore in 1970. The two shared the 1975 Nobel Prize in Physiology or Medicine with Renato Dulbecco for their discovery.

Commonly used examples of reverse transcriptases include:

  • HIV-1 reverse transcriptase from the 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
  • telomeres of eukaryotic chromosomes

Function

Viruses

The enzyme is encoded and used by reverse-transcribing viruses, which use the enzyme during the process of replication. Reverse-transcribing DNA viruses, such as the hepadnaviruses, transcribe their genomes into an RNA intermediate and then, using reverse transcriptase, back into DNA.

Eukaryotes

Self-replicating stretches of eukaryotic genomes known as retrotransposons utilise reverse transcriptase to move from one position in the genome to another via a RNA intermediate. They are found abundantly in the genomes of plants and animals. RNA template; this RNA is used as a template for DNA replication[1].

Prokaryotes

Reverse transcriptases are also found in bacterial retrons, distinct sequences which code for reverse transcriptase, and are used in the synthesis of msDNA.

Structure

Reverse transcriptase enzymes include an RNA-dependent RNase H family which is vital to their replication.

Replication fidelity

Reverse transcriptase has a high error rate when transcribing RNA into DNA since, unlike mutations to accumulate at an accelerated rate relative to proofread forms of replication. The commercially available reverse transcriptases produced by Promega are quoted by their manuals as having error rates in the range of 1 in 17,000 bases for AMV and 1 in 30,000 bases for M-MLV[2]

Applications

 

Antiviral drugs

For more details on this topic, see Reverse transcriptase inhibitor.

As HIV uses reverse transcriptase to copy its genetic material and generate new viruses (part of a retrovirus proliferation circle), specific drugs have been designed to disrupt the process and thereby suppress its growth. Collectively, these drugs are known as nevirapine (Viramune).

Molecular biology

For more details on this topic, see Reverse transcription polymerase chain reaction.

Reverse transcriptase is commonly used in research to apply the polymerase chain reaction technique to cDNA libraries from mRNA. The commercial availability of reverse transcriptase greatly improved knowledge in the area of molecular biology as, along with other enzymes, it allowed scientists to clone, sequence and characterise DNA.

See also

References

  1. ^ Lodish, et al, Molecular Cell Biology (2004), 5th edn, W. H. Freeman and Company, New York, ISBN 0-7167-4366-3
  2. ^ Promega kit instruction manual (1999)
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This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Reverse_transcriptase". A list of authors is available in Wikipedia.