Reverse transcriptase

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Reverse transcriptase
Image:1HMV.png 3D model of reverse transcriptase.
Systematic name	deoxynucleoside-triphosphate: DNA deoxynucleotidyltransferase (RNA-directed)
Other names	RNA-directed DNA polymerase DNA nucleotidyltransferase (RNA-directed) Revertase
EC number	Template:EC number
CAS number	9068-38-6
Disclaimer and references

In biochemistry, reverse transcriptase (or RNA-directed DNA polymerase) is an enzyme that transcribes RNA into DNA. That is, reverse transcriptase copies genetic information from RNA to DNA, which is the reverse of the more typical direction (DNA to RNA — see central dogma of molecular biology).

Every retrovirus has a reverse transcriptase enzyme, which enables it to transcribe the genetic information from its RNA into DNA, which can then be integrated into the host genome. Similarly, retrotransposons copy themselves to RNA and then, via reverse transcriptase, back to DNA.

Reverse transcriptases also occur in group II introns, bacterial msDNAs, hepadnaviruses, and caulimoviruses.

Reverse transcriptase has a high error rate (up to about 1 in 2,000 bases) when transcribing RNA into DNA. This high error rate allows retroviruses to mutate rapidly.

Telomerase is a reverse transcriptase, with catalysis provided by a protein subunit that is similar to retroviral reverse transcriptases. The RNA template is contained in the telomerase itself.

1 Structure
2 Examples
3 Reverse transcriptase inhibitors
4 Use in research
5 History
6 Workshops
7 See also
8 External links

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Structure

Reverse transcriptase enzymes include an RNA-dependent DNA polymerase and a DNA-dependent DNA polymerase, which work together to perform transcription. In addition to the transcription function, retroviral reverse transcriptases have an RNase domain, which belongs to the RNase H family.

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Examples

Examples of reverse transcriptase are:

HIV-1 reverse transcriptase from the human immunodeficiency virus type 1 (Template:PDB)
M-MuLV reverse transcriptase from the Moloney murine leukemia virus
AMV reverse transcriptase from the avian myeloblastosis virus

AMV Reverse Transciptase was made commercially available in the 1970's by Ed Houts in USA and Rob Hyams in UK

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Reverse transcriptase inhibitors

Since HIV uses reverse transcriptase, together with integrase, to infect human DNA with viral DNA, reverse transcriptase inhibitors are used to prevent this.

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Use in research

Reverse transcriptase is commonly used in research to apply the polymerase chain reaction technique to RNA. The classical PCR technique can only be applied to DNA strands, but with the help of reverse transcriptase, RNA can be transcribed into DNA, thus making PCR analysis of RNA molecules possible. The technique is collectively called Reverse Transcription-Polymerase Chain Reaction (RT-PCR). Reverse transcriptase is also used to create cDNA libraries from mRNA.

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History

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

The commercial availability of reverse trasncriptase moved forward the science of molecular biology, and this work is due to Life Sciences Inc in Florida, Ed Houts in Florida and Rob Hyams of the UK. This enzyme together with other DNA and RNA modifying enzymes as well as restriction endonucleases allowed scientists to clone, sequence and characterize DNA.

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