Reverse transcriptase 26214 215969388 2008-05-30T14:15:15Z ClueBot 4928500 Reverting possible vandalism by [[Special:Contributions/194.66.95.13|194.66.95.13]] to version by WriterHound. False positive? [[User:ClueBot/FalsePositives|Report it]]. Thanks, [[User:ClueBot]]. (401498) (Bot) {{Protbox |Name=Reverse Transcriptase |Photo=1HMV.png|250px |Caption=3D model of [[HIV]] reverse transcriptase |HGNCid = |Symbol = |AltSymbols = |Chromosome = |Arm = |Band = |LocusSupplementaryData = |Gene= |Gene_type= |Protein_length= |Molecular_weight= |Structure= |Type= |Functions= |Domains= |Motifs= |Alternative_products= |Catalytic_activity= |Cofactors= |Enzyme_regulation= |Km= |Vmax= |Biophysicochemical_properties= |Diseases= |Pharmaceuticals= |Biotechnology= |Taxa= |Cells= |Location= |Mods= |Names=Deoxynucleoside-triphosphate:<br>DNA deoxynucleotidyltransferase (RNA-directed)<br> *RNA-directed DNA polymerase *DNA nucleotidyltransferase (RNA-directed) *Revertase |Pathways= |Interactions= |Actions= |Agonists= |Antagonists= |Accession_numbers= |EntrezGene = |OMIM = |RefSeq = |UniProt = |PDB = |ECnumber = 2.7.7.49 |Codes= |Review= |Pages= }} In [[biochemistry]], a '''reverse transcriptase''', also known as '''RNA-dependent DNA polymerase''', is a [[DNA polymerase]] [[enzyme]] that [[transcription (genetics)|transcribes]] single-stranded [[RNA]] into double-stranded [[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. Well studied reverse transcriptases include: * HIV-1 reverse transcriptase from [[HIV|human immunodeficiency virus]] type 1 ({{PDB|1HMV}}) * M-MLV reverse transcriptase from the [[murine leukemia virus|Moloney murine leukemia virus]] * AMV reverse transcriptase from the [[Alpharetrovirus|avian myeloblastosis virus]] * [[Telomerase|Telomerase reverse transcriptase]] that maintains the [[telomere]]s of [[eukaryotic]] [[chromosomes]] ==Function== ===Viruses=== The enzyme is encoded and used by [[Virus classification|reverse-transcribing viruses]], which use the enzyme during the process of replication. Reverse-transcribing [[RNA virus]]es, such as [[retrovirus]]es, 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 virus]]es, such as the [[hepadnavirus]]es, transcribe their genomes into an RNA intermediate and then, using reverse transcriptase, back into DNA. ===Eukaryotes=== Self-replicating stretches of [[eukaryotic]] genomes known as [[retrotransposon]]s 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. [[Telomerase]] is another reverse transcriptase found in many eukaryotes, including humans, which carries its own [[RNA]] template; this RNA is used as a template for [[DNA replication]]<ref>Lodish, et al, ''Molecular Cell Biology'' (2004), 5th edn, W. H. Freeman and Company, New York, ISBN 0-7167-4366-3</ref>. ===Prokaryotes=== Reverse transcriptases are also found in bacterial [[retron]]s, distinct sequences which code for reverse transcriptase, and are used in the synthesis of [[multicopy single-stranded DNA|msDNA]]. ==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 a domain belonging to the [[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 [[DNA polymerase]]s, it has no [[proofreading]] ability. This high error rate allows [[mutation]]s 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<ref>[http://www.promega.com/pnotes/71/7807_22/7807_22_core.pdf Promega kit instruction manual (1999)]</ref> ==Applications== [[Image:Zidovudine.svg|thumb|200px|The molecular structure of [[zidovudine]] (AZT), a drug used to inhibit [[HIV]] reverse transcriptase]] ===Antiviral drugs=== {{details|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 [[reverse transcriptase inhibitor]]s 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). ===Molecular biology=== {{details|Reverse transcription polymerase chain reaction}} Reverse transcriptase is commonly used in research to apply the [[polymerase chain reaction]] technique to [[RNA]] in a technique called [[reverse transcription polymerase chain reaction]] (RT-PCR). The classical [[polymerase chain reaction|PCR]] technique can only be applied to [[DNA]] strands, but with the help of reverse transcriptase, RNA can be transcribed into DNA, thus making [[Polymerase chain reaction|PCR]] analysis of RNA molecules possible. Reverse transcriptase is also used to create [[cDNA library|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== *[[cDNA library]] *[[DNA polymerase]] *[[msDNA]] *[[Reverse transcribing virus]] *[[RNA polymerase]] *[[Telomerase]] *[[Retrotransposon marker]] ==External links== *[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=2.7.7.49 BRENDA database entry] - highly detailed information from a protein database * {{MeshName|RNA+Transcriptase}} * {{EC number|2.7.7.49}} ==References== {{reflist}} {{Kinases}} [[Category:EC 2.7.7]] [[Category:Molecular biology]] [[Category:Viral enzymes]] [[da:Revers transkriptase]] [[de:Reverse Transkriptase]] [[es:Transcriptasa inversa]] [[fr:Transcriptase inverse]] [[ko:역전사효소]] [[it:DNA polimerasi (RNA-dipendente)]] [[he:רוורס טרנסקריפטאז]] [[lt:Atvirkštinė transkriptazė]] [[nl:Reverse-transcriptase]] [[ja:逆転写酵素]] [[pl:Odwrotna transkryptaza]] [[pt:Transcriptase reversa]] [[ru:Обратная транскриптаза]] [[sv:Omvänt transkriptas]] [[ur:معکوس انتساخہ]] [[zh:逆轉錄酶]]