- Reverse transcriptase
Caption=3D model of
DNA deoxynucleotidyltransferase (RNA-directed)
*RNA-directed DNA polymerase
*DNA nucleotidyltransferase (RNA-directed)
ECnumber = 18.104.22.168
biochemistry, a reverse transcriptase, also known as RNA-dependent DNA polymerase, is a DNA polymerase enzymethat transcribes single-stranded RNAinto double-stranded DNA.It also helps in the formation of a double helix DNA once the RNA has been reverse transcribed into a single strand cDNA. Normal transcription involves the synthesis of RNA from DNA; hence, reverse transcription is the "reverse" of this.
Reverse transcriptase was discovered by
Howard Teminat the University of Wisconsin-Madison, and independently by David Baltimorein 1970. The two shared the 1975 Nobel Prize in Physiology or Medicinewith Renato Dulbeccofor their discovery.
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
The enzyme is encoded and used by reverse-transcribing viruses, which use the enzyme during the process of replication. Reverse-transcribing
RNA viruses, such as retroviruses, use the enzyme to reverse-transcribe their RNA genomes into DNA, which is then integrated into the host genome and replicated along with it. Reverse-transcribing DNA viruses, such as the hepadnaviruses, transcribe their genomes into an RNA intermediate and then, using reverse transcriptase, back into DNA.
Self-replicating stretches of
eukaryoticgenomes 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. Telomeraseis another reverse transcriptase found in many eukaryotes, including humans, which carries its own RNAtemplate; this RNA is used as a template for DNA replication[Lodish, et al, "Molecular Cell Biology" (2004), 5th edn, W. H. Freeman and Company, New York, ISBN 0-7167-4366-3] .
Reverse transcriptases are also found in bacterial
retrons, distinct sequences which code for reverse transcriptase, and are used in the synthesis of msDNA.
Reverse transcriptase enzymes include an RNA-dependent
DNA polymeraseand a DNA-dependent DNA polymerase, which work together to perform transcription. In addition to the transcription function, retroviral reverse transcriptases have a domain belonging to the RNase Hfamily which is vital to their replication.
Reverse transcriptase has a high error rate when transcribing RNA into DNA since, unlike
DNA polymerases, it has no proofreadingability. This high error rate allows mutations to accumulate at an accelerated rate relative to proofread forms of replication. The commercially available reverse transcriptases produced by Promegaare 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 [ [http://www.promega.com/pnotes/71/7807_22/7807_22_core.pdf Promega kit instruction manual (1999)] ]
HIVuses 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 reverse transcriptase inhibitors and include the nucleoside and nucleotide analogues zidovudine(trade name Retrovir), lamivudine(Epivir) and tenofovir(Viread), as well as non-nucleoside inhibitors, such as nevirapine(Viramune).
Reverse transcriptase is commonly used in research to apply the
polymerase chain reactiontechnique to RNAin a technique called reverse transcription polymerase chain reaction(RT-PCR). The classical PCR technique can be applied only to DNAstrands, but, with the help of reverse transcriptase, RNA can be transcribed into DNA, thus making PCR analysis of RNA molecules possible. Reverse transcriptase is used also to create 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.
Reverse transcribing virus
* [http://www.tibotec.com/bgdisplay.jhtml?itemname=HIV_discovery&product=none&s=2 animation of reverse transcriptase action and three reverse transcriptase inhibitors]
* [http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb33_1.html Molecule of the month] (September 2002) at the
Protein Data Bank
* [http://www.brenda.uni-koeln.de/php/result_flat.php4?ecno=22.214.171.124 BRENDA database entry] - highly detailed information from a protein database
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Look at other dictionaries:
Reverse-transcriptase — Transcriptase inverse Transcriptase inverse Général Synonymes EC … Wikipédia en Français
Reverse transcriptase — Transcriptase inverse Transcriptase inverse Général Synonymes EC … Wikipédia en Français
reverse transcriptase — n. an enzyme that makes DNA from RNA, found in retroviruses and widely used in recombinant DNA technology: cf. TRANSCRIPTASE … English World dictionary
reverse transcriptase — reverse transcriptase. См. ревертаза. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) … Молекулярная биология и генетика. Толковый словарь.
Reverse transcriptase — The enzyme that permits the human immunodeficiency virus (HIV) and other retroviruses to use their viral RNA as a template to make DNA. Reverse transcriptase is so named because it reverses the usual transcription of DNA into RNA and lets RNA be… … Medical dictionary
reverse transcriptase — an enzyme, found mainly in retroviruses, that catalyses the synthesis of DNA from RNA. It enables the viral RNA to be integrated into the host DNA. Reverse transcriptase inhibitors are antiviral drugs that inhibit this process; they include… … The new mediacal dictionary
reverse transcriptase — reverse′ tran•scrip′tase [[t]trænˈskrɪp teɪs, teɪz[/t]] n. biochem. a retrovirus enzyme that synthesizes DNA from viral RNA, the reverse of the usual DNA to RNA replication: used in genetic engineering • Etymology: 1970–75 … From formal English to slang
reverse transcriptase — (RT) An RNA dependent DNA polymerase that uses a viral RNA genome as a template to form a DNA copy; this is a reverse of the normal flow of genetic information, which proceeds from DNA to RNA … Dictionary of microbiology
reverse transcriptase — RNA directed DNA polymerase. Enzyme first discovered in retroviruses, that can construct double stranded DNA molecules from the single stranded RNA templates of their genomes. Reverse transcription now appears also to be involved in movement of… … Dictionary of molecular biology
reverse transcriptase — /tran skrip tays, tayz/, Biochem. a retrovirus enzyme that synthesizes DNA from viral RNA, the reverse of the usual DNA to RNA replication: used in genetic engineering to clone genes from RNA strands. [1970 75; TRANSCRIPT + ASE] * * * … Universalium