Reverse transcription in the context of "Reverse transcription polymerase chain reaction"

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⭐ Core Definition: Reverse transcription

A reverse transcriptase (RT) is an enzyme used to convert RNA to DNA, a process termed reverse transcription. Reverse transcriptases are used by viruses such as HIV and hepatitis B to replicate their genomes, by retrotransposon mobile genetic elements to proliferate within the host genome, and by eukaryotic cells to extend the telomeres at the ends of their linear chromosomes. The process does not violate the flows of genetic information as described by the classical central dogma, but rather expands it to include transfers of information from RNA to DNA.

Retroviral RT has three sequential biochemical activities: RNA-dependent DNA polymerase activity, ribonuclease H (RNase H), and DNA-dependent DNA polymerase activity. Collectively, these activities enable the enzyme to convert single-stranded RNA into double-stranded cDNA. In retroviruses and retrotransposons, this cDNA can then integrate into the host genome, from which new RNA copies can be made via host-cell transcription. 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.

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👉 Reverse transcription in the context of Reverse transcription polymerase chain reaction

Reverse transcription polymerase chain reaction (RT-PCR) is a laboratory technique combining reverse transcription of RNA into DNA (in this context called complementary DNA or cDNA) and amplification of specific DNA targets using polymerase chain reaction (PCR). It is primarily used to measure the amount of a specific RNA. This is achieved by monitoring the amplification reaction using fluorescence, a technique called real-time PCR or quantitative PCR (qPCR). Combined RT-PCR and qPCR are routinely used for analysis of gene expression and quantification of viral RNA in research and clinical settings.

The close association between RT-PCR and qPCR has led to metonymic use of the term qPCR to mean RT-PCR. Such use may be confusing, as RT-PCR can be used without qPCR, for example to enable molecular cloning, sequencing or simple detection of RNA. Conversely, qPCR may be used without RT-PCR, for example, to quantify the copy number of a specific piece of DNA.

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Reverse transcription in the context of Baltimore classification

Baltimore classification is a system used to classify viruses by their routes of transferring genetic information from the genome to messenger RNA (mRNA). Seven Baltimore groups, or classes, exist and are numbered in Roman numerals from I to VII. Groups are defined by whether the viral genome is made of deoxyribonucleic acid (DNA) or ribonucleic acid (RNA), whether the genome is single- or double-stranded, whether a single-stranded RNA genome is positive-sense (+) or negative-sense (–), and whether the virus makes DNA from RNA (reverse transcription (RT)). Viruses within Baltimore groups typically have the same replication method, but other characteristics such as virion structure are not directly related to Baltimore classification.

The seven Baltimore groups are for double-stranded DNA (dsDNA) viruses, single-stranded DNA (ssDNA) viruses, double-stranded RNA (dsRNA) viruses, positive-sense single-stranded RNA (+ssRNA) viruses, negative-sense single-stranded RNA (–ssRNA) viruses, ssRNA viruses that have a DNA intermediate in their life cycle (ssRNA-RT), and dsDNA viruses that have an RNA intermediate in their life cycle (dsDNA-RT). Only one class exists for ssDNA viruses because their genomes are converted to dsDNA before transcription regardless of sense. Some viruses belong to more than one Baltimore group, such as DNA viruses that have either dsDNA or ssDNA as their genome.

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Reverse transcription in the context of Retrotransposon

Retrotransposons (also called Class I transposable elements) are mobile elements which move in the host genome by converting their transcribed RNA into DNA through reverse transcription. Thus, they differ from Class II transposable elements, or DNA transposons, in utilizing an RNA intermediate for the transposition and leaving the transposition donor site unchanged.

Through reverse transcription, retrotransposons amplify themselves quickly to become abundant in eukaryotic genomes such as maize (49–78%) and humans (42%). They are only present in eukaryotes but share features with retroviruses such as HIV, for example, discontinuous reverse transcriptase-mediated extrachromosomal recombination.

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Reverse transcription in the context of Transposon

A transposable element (TE), also transposon, or jumping gene, mobile genetic element, a nucleic acid sequence in DNA that can change its position within a genome, an observation first made via careful genetic studies in corn, by Barbara McClintock (leading to an eventual Nobel Prize in Physiology/Medicine in 1983).

TEs are very common in all types of organisms in nature, including in plants and animals. As of 2008, there were at least two classes of TEs: Class I TEs or retrotransposons, which generally function via reverse transcription; and Class II TEs or DNA transposons, which encode the protein transposase (and sometimes other proteins), which they require for insertion, excision, or other TE functions.

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Reverse transcription in the context of Telomerase RNA component

Telomerase RNA component (TERC), also abbreviated TER or TR, is a non-coding RNA found in eukaryotes that is a component of the telomerase enzyme, which extends telomeres at the ends of linear chromosomes. TERC folds into a complex secondary structure which binds to and interacts with TERT, the protein component of telomerase, and serves as the RNA template for the reverse transcription reaction catalyzed by TERT. Telomerase RNAs differ greatly in length, sequence and structure between vertebrates, ciliates and yeasts, but they share a 5' pseudoknot structure close to the template sequence; vertebrate telomerase RNAs also share a 3' H/ACA snoRNA-like domain.

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LINKED FROM (PARENTS)
← Baltimore classification ← Reverse transcription polymerase chain reaction ← Retrotransposon ← Transposon ← RT-PCR ← Telomerase RNA component ← Transposons
LINKS TO (CHILDREN)
Enzyme → RNA → DNA → Virus → HIV → Hepatitis B virus → Retrotransposon → Eukaryote → Telomeres → Chromosome → Central dogma of molecular biology → DNA polymerase → Ribonuclease H → Transcription (biology) → Molecular cloning → RNA sequencing → Polymerase chain reaction → DNA microarray →