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Reverse Transcriptase
A reverse transcriptase (RT) is an enzyme used to convert RNA genome 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Enzyme
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecules known as product (chemistry), products. Almost all metabolism, metabolic processes in the cell (biology), cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme, pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts include Ribozyme, catalytic RNA molecules, also called ribozymes. They are sometimes descr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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University Of Wisconsin–Madison
The University of Wisconsin–Madison (University of Wisconsin, Wisconsin, UW, UW–Madison, or simply Madison) is a public land-grant research university in Madison, Wisconsin, United States. It was founded in 1848 when Wisconsin achieved statehood and is the flagship campus of the University of Wisconsin System. The main campus is located on the shores of Lake Mendota; the university also owns and operates a arboretum south of the main campus. UW–Madison is organized into 13 schools and colleges, which enrolled approximately 34,200 undergraduate and 14,300 graduate and professional students in 2024. Its academic programs include 136 undergraduate majors, 148 master's degree programs, and 120 doctoral programs. Wisconsin is one of the founding members of the Association of American Universities. It is considered a Public Ivy and is classified as an R1 University. UW–Madison was also the home of both the prominent "Wisconsin School" of economics and diplomatic h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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RNA Virus
An RNA virus is a virus characterized by a ribonucleic acid (RNA) based genome. The genome can be single-stranded RNA (ssRNA) or double-stranded (Double-stranded RNA, dsRNA). Notable human diseases caused by RNA viruses include influenza, SARS, MERS, COVID-19, Dengue virus, hepatitis C, hepatitis E, West Nile fever, Ebola virus disease, rabies, polio, mumps, and measles. All known RNA viruses, that is viruses that use a homologous RNA-dependent polymerase for replication, are categorized by the International Committee on Taxonomy of Viruses (ICTV) into the realm ''Riboviria''. This includes RNA viruses belonging to ''Group III'', ''Group IV'' or ''Group V'' of the Virus classification#Baltimore classification, Baltimore classification system as well as ''Group VI. Group VI'' viruses are retroviruses, viruses with RNA genetic material that use DNA intermediates in their Viral life cycle, life cycle including HIV-1 and HIV-2 which cause AIDS. The majority of such RNA viruses fall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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HIV-1 Reverse Transcriptase With Active Sites
The subtypes of HIV include two main subtypes, known as HIV type 1 (HIV-1) and HIV type 2 (HIV-2). These subtypes have distinct genetic differences and are associated with different epidemiological patterns and clinical characteristics. HIV-1 exhibits a genetic relation to viruses indigenous to chimpanzees and gorillas that inhabit West Africa, while HIV-2 viruses are affiliated with viruses present in the sooty mangabey, a vulnerable West African primate. HIV-1 viruses can be further stratified into groups M, N, O, and P. Among these, HIV-1 group M viruses are the most prevalent, infecting nearly 90% of people living with HIV and are responsible for the global AIDS pandemic. Group M can be further subdivided into subtypes based on genetic sequence data. Certain subtypes are known for their increased virulence or drug resistance to different medications used to treat HIV. HIV-2 viruses are generally considered to be less virulent and less transmissible than HIV-1 M group viru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Chromosomes
A chromosome is a package of DNA containing part or all of the genetic material of an organism. In most chromosomes, the very long thin DNA fibers are coated with nucleosome-forming packaging proteins; in eukaryotic cells, the most important of these proteins are the histones. Aided by chaperone proteins, the histones bind to and condense the DNA molecule to maintain its integrity. These eukaryotic chromosomes display a complex three-dimensional structure that has a significant role in transcriptional regulation. Normally, chromosomes are visible under a light microscope only during the metaphase of cell division, where all chromosomes are aligned in the center of the cell in their condensed form. Before this stage occurs, each chromosome is duplicated ( S phase), and the two copies are joined by a centromere—resulting in either an X-shaped structure if the centromere is located equatorially, or a two-armed structure if the centromere is located distally; the joined ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Eukaryotic
The eukaryotes ( ) constitute the Domain (biology), domain of Eukaryota or Eukarya, organisms whose Cell (biology), cells have a membrane-bound cell nucleus, nucleus. All animals, plants, Fungus, fungi, seaweeds, and many unicellular organisms are eukaryotes. They constitute a major group of Outline of life forms, life forms alongside the two groups of prokaryotes: the Bacteria and the Archaea. Eukaryotes represent a small minority of the number of organisms, but given their generally much larger size, their collective global biomass is much larger than that of prokaryotes. The eukaryotes emerged within the archaeal Kingdom (biology), kingdom Asgard (Archaea), Promethearchaeati and its sole phylum Promethearchaeota. This implies that there are only Two-domain system, two domains of life, Bacteria and Archaea, with eukaryotes incorporated among the Archaea. Eukaryotes first emerged during the Paleoproterozoic, likely as Flagellated cell, flagellated cells. The leading evolutiona ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Telomere
A telomere (; ) is a region of repetitive nucleotide sequences associated with specialized proteins at the ends of linear chromosomes (see #Sequences, Sequences). Telomeres are a widespread genetic feature most commonly found in eukaryotes. In most, if not all species possessing them, they protect the terminal regions of DNA, chromosomal DNA from progressive degradation and ensure the integrity of linear chromosomes by preventing DNA repair systems from mistaking the very ends of the DNA strand for a double-strand break. Discovery The existence of a special structure at the ends of chromosomes was independently proposed in 1938 by Hermann Joseph Muller, studying the fruit fly ''Drosophila melanogaster'', and in 1939 by Barbara McClintock, working with maize. Muller observed that the ends of irradiated fruit fly chromosomes did not present alterations such as deletions or inversions. He hypothesized the presence of a protective cap, which he coined "telomeres", from the Greek ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Telomerase Reverse Transcriptase
Telomerase reverse transcriptase (abbreviated to TERT, or hTERT in humans) is a catalytic subunit of the enzyme telomerase, which, together with the telomerase RNA component (TERC), comprises the most important unit of the telomerase complex. Telomerases are part of a distinct subgroup of RNA-dependent polymerases. Telomerase lengthens telomeres in DNA strands, thereby allowing senescent cells that would otherwise become postmitotic and undergo apoptosis to exceed the Hayflick limit and become potentially immortal, as is often the case with cancerous cells. To be specific, TERT is responsible for catalyzing the addition of nucleotides in a TTAGGG sequence to the ends of a chromosome's telomeres. This addition of repetitive DNA sequences prevents degradation of the chromosomal ends following multiple rounds of replication. hTERT absence (usually as a result of a chromosomal mutation) is associated with the disorder Cri du chat. Function Telomerase is a ribonucleopr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Alpharetrovirus
''Alpharetrovirus'' is a genus of viruses in the family ''Retroviridae A retrovirus is a type of virus that inserts a DNA copy of its RNA genome into the DNA of a host cell that it invades, thus changing the genome of that cell. After invading a host cell's cytoplasm, the virus uses its own reverse transcriptase ...''. The genus contains nine species. Taxonomy The genus contains the following species, listed by scientific name and followed by the exemplar virus of the species: * ''Alpharetrovirus avicarmilhil2'', Avian carcinoma Mill Hill virus 2 * ''Alpharetrovirus avifujsar'', Fujinami sarcoma virus * ''Alpharetrovirus avileu'', Avian leukosis virus * ''Alpharetrovirus avimyebla'', Avian myeloblastosis virus * ''Alpharetrovirus avimyecyt29'', Avian myelocytomatosis virus 29 * ''Alpharetrovirus avirousar'', Rous sarcoma virus * ''Alpharetrovirus avisar10'', Avian sarcoma virus CT10 * ''Alpharetrovirus aviUR2sar'', UR2 sarcoma virus * ''Alpharetrovirus aviY73sar'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Kilodalton
The dalton or unified atomic mass unit (symbols: Da or u, respectively) is a unit of mass defined as of the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state and at rest. It is a non-SI unit accepted for use with SI. The word "unified" emphasizes that the definition was accepted by both IUPAP and IUPAC. The atomic mass constant, denoted , is defined identically. Expressed in terms of , the atomic mass of carbon-12: . Its value in SI units is an experimentally determined quantity. The 2022 CODATA recommended value of the atomic mass constant expressed in the SI base unit kilogram is:This value serves as a conversion factor of mass from daltons to kilograms, which can easily be converted to grams and other metric units of mass. The 2019 revision of the SI redefined the kilogram by fixing the value of the Planck constant (), improving the precision of the atomic mass constant expressed in SI units by anchoring it to fixed physical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Renato Dulbecco
Renato Dulbecco ( , ; February 22, 1914 – February 19, 2012) was an Italian–American virologist who won the 1975 Nobel Prize in Physiology or Medicine for his work on oncoviruses, which are viruses that can cause cancer when they infect animal cells. He studied at the University of Turin under Giuseppe Levi, along with fellow students Salvador Luria and Rita Levi-Montalcini, who also moved to the U.S. with him and won Nobel prizes. He was drafted into the Italian army in World War II, but later joined the resistance. Early life Dulbecco was born in Catanzaro (Calabria, Southern Italy), but spent his childhood and grew up in Liguria, in the coastal city Imperia. He graduated from high school at 16, then moved to the University of Turin. Despite a strong interest in mathematics and physics, he decided to study medicine. At only 22, he graduated in morbid anatomy and pathology under the supervision of professor Giuseppe Levi. During these years he met Salvador Luria and Rit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Nobel Prize In Physiology Or Medicine
The Nobel Prize in Physiology or Medicine () is awarded yearly by the Nobel Assembly at the Karolinska Institute for outstanding discoveries in physiology or medicine. The Nobel Prize is not a single prize, but five separate prizes that, according to Alfred Nobel's 1895 will, are awarded "to those who, during the preceding year, have conferred the greatest benefit to humankind". Nobel Prizes are awarded in the fields of Physics, Medicine or Physiology, Chemistry, Literature, and Peace. The Nobel Prize is presented annually on the anniversary of Alfred Nobel's death, 10 December. As of 2024, 115 Nobel Prizes in Physiology or Medicine have been awarded to 229 laureates, 216 men and 13 women. The first one was awarded in 1901 to the German physiologist, Emil von Behring, for his work on serum therapy and the development of a vaccine against diphtheria. The first woman to receive the Nobel Prize in Physiology or Medicine, Gerty Cori, received it in 1947 for her role in elucida ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |