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Retrovirus
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 enzyme to produce DNA from its RNA genome, the reverse of the usual pattern, thus ''retro'' (backward). The new DNA is then retroviral integration, incorporated into the host cell genome by an integrase enzyme, at which point the retroviral DNA is referred to as a provirus. The host cell then treats the viral DNA as part of its own genome, transcribing and translating the viral genes along with the cell's own genes, producing the proteins required to assemble new copies of the virus. Many retroviruses cause serious diseases in humans, other mammals, and birds. Retroviruses have many subfamilies in three basic groups. * Oncovirus, Oncoretroviruses (cancer-causing retroviruses) include human T-lymphotropic virus (HTLV) causing a type of leuk ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endogenous Retrovirus
Endogenous retroviruses (ERVs) are endogenous viral elements in the genome that closely resemble and can be derived from retroviruses. They are abundant in the genomes of jawed vertebrates, and they comprise up to 5–8% of the human genome (lower estimates of ~1%). An ERV is a vertically inherited proviral sequence and a subclass of a type of gene called a transposon, which can normally be packaged and moved within the genome to serve a vital role in gene expression and in regulation. ERVs, however, lack most transposon functions, are typically not infectious, and are often defective genomic remnants of the retroviral replication cycle. They are distinguished as germline provirus retroelements due to their integration and reverse-transcription into the nuclear genome of the host cell. Researchers have suggested that retroviruses evolved from a type of transposon called a retrotransposon, a Class I element; these genes can mutate and instead of moving to another locati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retroviruses
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 enzyme to produce DNA from its RNA genome, the reverse of the usual pattern, thus ''retro'' (backward). The new DNA is then incorporated into the host cell genome by an integrase enzyme, at which point the retroviral DNA is referred to as a provirus. The host cell then treats the viral DNA as part of its own genome, transcribing and translating the viral genes along with the cell's own genes, producing the proteins required to assemble new copies of the virus. Many retroviruses cause serious diseases in humans, other mammals, and birds. Retroviruses have many subfamilies in three basic groups. * Oncoretroviruses (cancer-causing retroviruses) include human T-lymphotropic virus (HTLV) causing a type of leukemia in humans, and murine leuk ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gammaretrovirus
''Gammaretrovirus'' is a genus in the ''Retroviridae'' family. Example species are the murine leukemia virus and the feline leukemia virus. They cause various sarcomas, leukemias and immune deficiencies in mammals, reptiles and birds. Introduction Many endogenous retroviruses, closely related to exogenous gammaretroviruses, are present in the DNA of mammals (including humans), birds, reptiles and amphibians. Many also share a conserved RNA structural element called a core encapsidation signal. The avian reticuloendotheliosis viruses are not strictly avian viruses—it appears that reticuloendotheliosis viruses are mammalian viruses that were accidentally introduced into birds in the 1930s during research on malaria. As a potential vector for gene therapy, gammaretroviruses have some advantages over HIV as a lentiviral vector. Specifically, the gammaretroviral packaging system does not require the incorporation of any sequences overlapping with coding sequences of gag, pol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Betaretrovirus
''Betaretrovirus'' is a genus of viruses in the Family (biology), family ''Retroviridae''. Example of viruses in the genus include: Mouse mammary tumor virus, enzootic nasal tumor virus (ENTV-1, ENTV-2), and simian retrovirus types 1, 2 and 3 (SRV-1, SRV-2, SRV-3). Taxonomy The genus contains the following species, listed by scientific name and followed by the exemplar virus of the species: * ''Betaretrovirus lan'', Langur virus * ''Betaretrovirus maspfimon'', Mason-Pfizer monkey virus * ''Betaretrovirus murmamtum'', Mouse mammary tumor virus * ''Betaretrovirus ovijaa'', Jaagsiekte sheep retrovirus * ''Betaretrovirus squmon'', Squirrel monkey retrovirus References External links Viralzone: Betaretrovirus Betaretroviruses Virus genera {{Virus-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oncovirus
An oncovirus or oncogenic virus is a virus that can cause cancer. This term originated from studies of acutely transforming retroviruses in the 1950–60s, when the term ''oncornaviruses'' was used to denote their RNA virus origin. With the letters ''RNA'' removed, it now refers to any virus with a DNA or RNA genome causing cancer and is synonymous with ''tumor virus'' or ''cancer virus''. The vast majority of human and animal viruses do not cause cancer, probably because of longstanding co-evolution between the virus and its host. Oncoviruses have been important not only in epidemiology, but also in investigations of cell cycle control mechanisms such as the retinoblastoma protein. The World Health Organization's International Agency for Research on Cancer estimated that in 2002, infection caused 17.8% of human cancers, with 11.9% caused by one of seven viruses. A 2020 study of 2,658 samples from 38 different types of cancer found that 16% were associated with a virus. These ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deltaretrovirus
''Deltaretrovirus'' is a genus of the ''Retroviridae'' family. It consists of exogenous horizontally transmitted viruses found in several groups of mammals. The genus contains Bovine leukemia virus and three species of primate T-lymphotropic virus. The genus of viruses is known for its propensity to target immune cells and oncogenicity, evident in the names of the four named species. Infection is usually asymptomatic, but inflammation and cancer can develop over time. Classification The genus contains the following species, listed by scientific name and followed by the exemplar virus of the species: * ''Deltaretrovirus bovleu'', Bovine leukemia virus * ''Deltaretrovirus priTlym1'', Primate T-lymphotropic virus 1 * ''Deltaretrovirus priTlym2'', Primate T-lymphotropic virus 2 * ''Deltaretrovirus priTlym3'', Primate T-lymphotropic virus 3 Two additional PTLVs are known but not recognized: HTLV-4 ( South Cameroon, 2005) and STLV-5 (Mac B43 strain, highly divergent PTLV-1). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Human T-lymphotropic Virus
The primate T-lymphotropic viruses (PTLVs) are a group of retroviruses that infect primates, using their lymphocytes to reproduce. The ones that infect humans are known as human T-lymphotropic virus (HTLV), and the ones that infect Old World monkeys are called simian T-lymphotropic viruses (STLVs). PTLVs are named for their ability to cause adult T-cell leukemia/lymphoma, but in the case of HTLV-1 it can also cause a demyelinating disease called tropical spastic paraparesis. On the other hand, newer PTLVs are simply placed into the group by similarity and their connection to human disease remains unclear. HTLVs have evolved from STLVs by interspecies transmission. Within each species of PTLV, the HTLV is more similar to its cognate STLV than to the other HTLVs. There are currently three species of PTLVs recognized by the ICTV (P/H/STLV-1, -2, -3), plus two that are reported but unrecognized (HTLV-4, STLV-5). The first known, and still most medically important PTLV is HTLV-1, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virus
A virus is a submicroscopic infectious agent that replicates only inside the living Cell (biology), cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898, more than 16,000 of the millions of List of virus species, virus species have been described in detail. The study of viruses is known as virology, a subspeciality of microbiology. When infected, a host cell is often forced to rapidly produce thousands of copies of the original virus. When not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent viral particles, or ''virions'', consisting of (i) genetic material, i.e., long ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Provirus
A provirus is a virus genome that is integrated into the DNA of a host cell. In the case of bacterial viruses (bacteriophages), proviruses are often referred to as prophages. However, proviruses are distinctly different from prophages and these terms should not be used interchangeably. Unlike prophages, proviruses do not excise themselves from the host genome when the host cell is stressed. This state can be a stage of virus replication, or a state that persists over longer periods of time as either inactive viral infections or an endogenous viral element. In inactive viral infections the virus will not replicate itself except through replication of its host cell. This state can last over many host cell generations. Endogenous retroviruses are always in the state of a provirus. When a (nonendogenous) retrovirus invades a cell, the RNA of the retrovirus is reverse-transcribed into DNA by reverse transcriptase, then inserted into the host genome by an integrase. A provirus does n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
AIDS
The HIV, human immunodeficiency virus (HIV) is a retrovirus that attacks the immune system. Without treatment, it can lead to a spectrum of conditions including acquired immunodeficiency syndrome (AIDS). It is a Preventive healthcare, preventable disease. It can be managed with treatment and become a manageable chronic health condition. While there is no cure or vaccine for HIV, Management of HIV/AIDS, antiretroviral treatment can slow the course of the disease, and if used before significant disease progression, can extend the life expectancy of someone living with HIV to a nearly standard level. An HIV-positive person on treatment can expect to live a normal life, and die with the virus, not of it. Effective #Treatment, treatment for HIV-positive people (people living with HIV) involves a life-long regimen of medicine to suppress the virus, making the viral load undetectable. Treatment is recommended as soon as the diagnosis is made. An HIV-positive person who has an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
