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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] [Amazon] |
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] [Amazon] |
Spumavirus
''Spumaretrovirinae'', commonly called spumaviruses (, Latin for "foam") or foamyviruses, is a subfamily of the ''Retroviridae'' family. ICTVMaster Species List 2018a v1MSL including all taxa updates since the 2017 release. Fall 2018 (MSL #33) Spumaviruses are exogenous viruses that have specific morphology with prominent surface spikes. The virions contain significant amounts of double-stranded full-length DNA, and assembly is rather unusual in these viruses. Spumaviruses are unlike most enveloped viruses in that the envelope membrane is acquired by budding through the endoplasmic reticulum instead of the cytoplasmic membrane. Some spumaviruses, including the equine foamy virus (EFV), bud from the cytoplasmic membrane. Some examples of these viruses are simian foamy virus and the human foamy virus Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are Hominidae, gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Lentivirus
''Lentivirus'' is a genus of retroviruses that cause chronic and deadly diseases characterized by long incubation periods, in humans and other mammalian species. The genus includes the human immunodeficiency virus (HIV), which causes AIDS. Lentiviruses are distributed worldwide, and are known to be hosted in apes, cows, goats, horses, cats, and sheep as well as several other mammals. Lentiviruses can integrate a significant amount of viral complementary DNA into the DNA of the host cell and can efficiently infect nondividing cells, so they are one of the most efficient methods of gene delivery. They can become endogenous, integrating their genome into the host germline genome, so that the virus is henceforth inherited by the host's descendants. Classification Five serogroups of lentiviruses are recognized, reflecting the vertebrate hosts with which they are associated (primates, sheep and goats, horses, domestic cats, and cattle). The primate lentiviruses are distinguished ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Spumaretrovirinae
''Spumaretrovirinae'', commonly called spumaviruses (, Latin for "foam") or foamyviruses, is a subfamily of the ''Retroviridae'' family. ICTVMaster Species List 2018a v1MSL including all taxa updates since the 2017 release. Fall 2018 (MSL #33) Spumaviruses are exogenous viruses that have specific morphology with prominent surface spikes. The virions contain significant amounts of double-stranded full-length DNA, and assembly is rather unusual in these viruses. Spumaviruses are unlike most enveloped viruses in that the envelope membrane is acquired by budding through the endoplasmic reticulum instead of the cytoplasmic membrane. Some spumaviruses, including the equine foamy virus (EFV), bud from the cytoplasmic membrane. Some examples of these viruses are simian foamy virus and the human foamy virus Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are Hominidae, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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] [Amazon] |
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] [Amazon] |
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] [Amazon] |
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] [Amazon] |
HIV-1
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 vi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
HIV-2
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 vir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Orthoretrovirinae
''Orthoretrovirinae'' is a subfamily of viruses belonging to ''Retroviridae'', a family of enveloped viruses that replicate in a host cell through the process of reverse transcription. The subfamily currently includes six genera, of which ''Lentivirus'' contains the human immunodeficiency virus (HIV). These viruses cause a variety of tumors, malignancies and immune deficiency disease in humans, other mammals and birds. A few, like Simian immunodeficiency virus Simian immunodeficiency virus (SIV) is a species of retrovirus that cause persistent infections in at least 45 species of non-human primates. Based on analysis of strains found in four species of monkeys from Bioko Island, which was isolated fr ... (SIV), apparently cause no disease in their natural hosts. References Retroviridae Virus subfamilies {{virus-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
