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. Once inside the 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 (backwards). 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.
Rubella virus (RuV) is the pathogenic agent of the disease rubella, transmitted only between humans via the respiratory route, and is the main cause of congenital rubella syndrome when infection occurs during the first weeks of pregnancy.
A viral protein is both a component and a product of a virus. Viral proteins are grouped according to their functions, and groups of viral proteins include structural proteins, nonstructural proteins, regulatory proteins, and accessory proteins. Viruses are non-living and do not have the means to reproduce on their own, instead depending on their host cell's resources in order to reproduce. Thus, viruses do not code for many of their own viral proteins, and instead use the host cell's machinery to produce the viral proteins they require for replication.
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.
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.
Alphavirus is a genus of RNA viruses, the sole genus in the Togaviridae family. Alphaviruses belong to group IV of the Baltimore classification of viruses, with a positive-sense, single-stranded RNA genome. There are 32 alphaviruses, which infect various vertebrates such as humans, rodents, fish, birds, and larger mammals such as horses, as well as invertebrates. Alphaviruses that could infect both vertebrates and arthropods are referred dual-host alphaviruses, while insect-specific alphaviruses such as Eilat virus and Yada yada virus are restricted to their competent arthropod vector. Transmission between species and individuals occurs mainly via mosquitoes, making the alphaviruses a member of the collection of arboviruses – or arthropod-borne viruses. Alphavirus particles are enveloped, have a 70 nm diameter, tend to be spherical, and have a 40 nm isometric nucleocapsid.
Myristoylation is a lipidation modification where a myristoyl group, derived from myristic acid, is covalently attached by an amide bond to the alpha-amino group of an N-terminal glycine residue. Myristic acid is a 14-carbon saturated fatty acid (14:0) with the systematic name of n-Tetradecanoic acid. This modification can be added either co-translationally or post-translationally. N-myristoyltransferase (NMT) catalyzes the myristic acid addition reaction in the cytoplasm of cells. This lipidation event is the most found type of fatty acylation and is common among many organisms including animals, plants, fungi, protozoans and viruses. Myristoylation allows for weak protein–protein and protein–lipid interactions and plays an essential role in membrane targeting, protein–protein interactions and functions widely in a variety of signal transduction pathways.
The genome and proteins of HIV have been the subject of extensive research since the discovery of the virus in 1983. "In the search for the causative agent, it was initially believed that the virus was a form of the Human T-cell leukemia virus (HTLV), which was known at the time to affect the human immune system and cause certain leukemias. However, researchers at the Pasteur Institute in Paris isolated a previously unknown and genetically distinct retrovirus in patients with AIDS which was later named HIV." Each virion comprises a viral envelope and associated matrix enclosing a capsid, which itself encloses two copies of the single-stranded RNA genome and several enzymes. The discovery of the virus itself occurred two years following the report of the first major cases of AIDS-associated illnesses.
Jaagsiekte sheep retrovirus (JSRV) is a betaretrovirus which is the causative agent of a contagious lung cancer in sheep, called ovine pulmonary adenocarcinoma.
Rous sarcoma virus (RSV) is a retrovirus and is the first oncovirus to have been described. It causes sarcoma in chickens.
The murine leukemia viruses are retroviruses named for their ability to cause cancer in murine (mouse) hosts. Some MLVs may infect other vertebrates. MLVs include both exogenous and endogenous viruses. Replicating MLVs have a positive sense, single-stranded RNA (ssRNA) genome that replicates through a DNA intermediate via the process of reverse transcription.
Simian foamy virus (SFV) is a species of the genus Spumavirus that belongs to the family of Retroviridae. It has been identified in a wide variety of primates, including prosimians, New World and Old World monkeys, as well as apes, and each species has been shown to harbor a unique (species-specific) strain of SFV, including African green monkeys, baboons, macaques, and chimpanzees. As it is related to the more well-known retrovirus human immunodeficiency virus (HIV), its discovery in primates has led to some speculation that HIV may have been spread to the human species in Africa through contact with blood from apes, monkeys, and other primates, most likely through bushmeat-hunting practices.
The gag-onc fusion protein is a general term for a fusion protein formed from a group-specific antigen ('gag') gene and that of an oncogene ('onc'), a gene that plays a role in the development of a cancer. The name is also written as Gag-v-Onc, with "v" indicating that the Onc sequence resides in a viral genome. Onc is a generic placeholder for a given specific oncogene, such as C-jun..
Visna-maedi virus from the genus Lentivirus and subfamily Orthoretrovirinae, is a retrovirus that causes encephalitis and chronic pneumonitis in sheep. It is known as visna when found in the brain, and maedi when infecting the lungs. Lifelong, persistent infections in sheep occur in the lungs, lymph nodes, spleen, joints, central nervous system, and mammary glands; The condition is sometimes known as ovine progressive pneumonia (OPP), particularly in the United States, or Montana sheep disease. White blood cells of the monocyte/macrophage lineage are the main target of the virus.
This family represents the bovine leukaemia virus RNA encapsidation (packaging) signal, which is essential for efficient viral replication.
Bevirimat is an anti-HIV drug derived from a betulinic acid-like compound, first isolated from Syzygium claviflorum, a Chinese herb. It is believed to inhibit HIV by a novel mechanism, so-called maturation inhibition. It is not currently U.S. Food and Drug Administration (FDA) approved. It was originally developed by the pharmaceutical company Panacos and reached Phase IIb clinical trials. Myriad Genetics announced on January 21, 2009 the acquisition of all rights to bevirimat for $7M USD. On June 8, 2010 Myriad Genetics announced that it was halting the development of maturation inhibitors, including bevirimat, to focus more on their oncology portfolio.
Bovine immunodeficiency virus (BIV) is a retrovirus belonging to the genus Lentivirus. It is similar to the human immunodeficiency virus (HIV) and infects cattle. The cells primarily infected are lymphocytes and monocytes/macrophages.
Retroviral matrix proteins are components of envelope-associated capsids of retroviruses. These proteins line the inner surface of viral envelopes and are associated with viral membranes.
Mason-Pfizer monkey virus (M-PMV), formerly Simian retrovirus (SRV), is a species of retroviruses that usually infect and cause a fatal immune deficiency in Asian macaques. The ssRNA virus appears sporadically in mammary carcinoma of captive macaques at breeding facilities which expected as the natural host, but the prevalence of this virus in feral macaques remains unknown. M-PMV was transmitted naturally by virus-containing body fluids, via biting, scratching, grooming, and fighting. Cross contaminated instruments or equipment (fomite) can also spread this virus among animals.
Rio Negro virus is an alphavirus that was first isolated in Argentina in 1980. The virus was first called Ag80-663 but was renamed to Rio Negro virus in 2005. It is a former member of the Venezuelan equine encephalitis complex (VEEC), which are a group of alphaviruses in the Americas that have the potential to emerge and cause disease. Río Negro virus was recently reclassified as a distinct species. Closely related viruses include Mucambo virus and Everglades virus.
