|
Metaviridae
''Metaviridae'' is a family of viruses which exist as Ty3-gypsy LTR retrotransposons in a eukaryotic host's genome. They are closely related to retroviruses: members of the family ''Metaviridae'' share many genomic elements with retroviruses, including length, organization, and genes themselves. This includes genes that encode reverse transcriptase, integrase, and capsid proteins. The reverse transcriptase and integrase proteins are needed for the retrotransposon activity of the virus. In some cases, virus-like particles can be formed from capsid proteins. Some assembled virus-like particles of members of the family ''Metaviridae'' can penetrate and infect previously uninfected cells. An example of this is the gypsy, a retroelement found in the ''Drosophila melanogaster'' genome. The ability to infect other cells is determined by the presence of the retroviral ''env'' genes which encode coat proteins. ''Metaviridae'' is a family of retrotransposons found in all eukaryotes known ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metaviridae
''Metaviridae'' is a family of viruses which exist as Ty3-gypsy LTR retrotransposons in a eukaryotic host's genome. They are closely related to retroviruses: members of the family ''Metaviridae'' share many genomic elements with retroviruses, including length, organization, and genes themselves. This includes genes that encode reverse transcriptase, integrase, and capsid proteins. The reverse transcriptase and integrase proteins are needed for the retrotransposon activity of the virus. In some cases, virus-like particles can be formed from capsid proteins. Some assembled virus-like particles of members of the family ''Metaviridae'' can penetrate and infect previously uninfected cells. An example of this is the gypsy, a retroelement found in the ''Drosophila melanogaster'' genome. The ability to infect other cells is determined by the presence of the retroviral ''env'' genes which encode coat proteins. ''Metaviridae'' is a family of retrotransposons found in all eukaryotes known ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metavirus
''Metavirus'' is a genus of viruses in the family ''Metaviridae''. They are retrotransposons that invade a eukaryotic host genome and may only replicate once the virus has infected the host. These genetic elements exist to infect and replicate in their host genome and are derived from ancestral elements unrelated from their host. ''Metavirus'' may use several different hosts for transmission, and has been found to be transmissible through ovule and pollen of some plants. ''Metavirus'' contains five families of the ''Ty3/Gypsy'' element with either one or two open-reading frames; these families are ''mdg1, mdg3, blastopia,'' ''412,'' and ''micropia''. Each of the five families contains either one or two open-reading frames, ''gag3'' and/or ''pol3''. There is evidence to support that amino acid deprivation in the elements host genome has frequently caused a frameshift towards the ''Ty3'' element. ''Metavirus'' corresponds with the ''Ogre/Tat'' gene lineage. Morphology Species of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LTR Retrotransposon
LTR retrotransposons are class I transposable element characterized by the presence of long terminal repeats (LTRs) directly flanking an internal coding region. As retrotransposons, they mobilize through reverse transcription of their mRNA and integration of the newly created cDNA into another location. Their mechanism of retrotransposition is shared with retroviruses, with the difference that most LTR-retrotransposons do not form infectious particles that leave the cells and therefore only replicate inside their genome of origin. Those that do (occasionally) form virus-like particles are classified under ''Ortervirales''. Their size ranges from a few hundred base pairs to 25kb, for example the Ogre retrotransposon in the pea genome. In plant genomes, LTR retrotransposons are the major repetitive sequence class, for example, constituting more than 75% of the maize genome. LTR retrotransposons make up about 8% of the human genome and approximately 10% of the mouse genome. Struct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Belpaoviridae
''Semotivirus'' is the only genus of viruses in the family ''Belpaoviridae'' (formerly included in the family ''Metaviridae''). Species exist as retrotransposons in a eukaryotic host's genome. BEL/pao transposons are only found in animals. Species The genus contains the following species: * ''Anopheles gambiae Moose virus'' * '' Antheraea semotivirus Tamy'' * '' Ascaris lumbricoides Tas virus'' * '' Bombyx mori Pao virus'' * ''Caenorhabditis elegans Cer13 virus ''Caenorhabditis elegans Cer13 virus'' is a species of virus in the genus '' Semotivirus'' and the family ''Belpaoviridae''. It exists as retrotransposons in the ''Caenorhabditis elegans ''Caenorhabditis elegans'' () is a free-living transpare ...'' * '' Drosophila melanogaster Bel virus'' * '' Drosophila melanogaster Roo virus'' * '' Drosophila semotivirus Max'' * '' Drosophila simulans Ninja virus'' * '' Schistosoma semotivirus Sinbad'' * '' Takifugu rubripes Suzu virus'' References * Frame IG, Cutfield JF, Po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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. 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. Although retroviruses have different subfamilies, they have three basic groups: the oncoretroviruses (oncogenic retroviruses), the lentiviruses (slow retroviruses) and the spumaviruses (foamy viruses). The oncoretroviruses are able to cause cancer in some species, the lentiviru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ortervirales
''Ortervirales'' is an order that contains all accepted species of single-stranded RNA viruses that replicate through a DNA intermediate (Group VI) and all accepted species of double-stranded DNA viruses (except ''Hepadnaviridae'') that replicate through an RNA intermediate (Group VII). The name is derived from the reverse of retro. All reverse-transcribing viruses possess significant similarities to each other. Their reverse transcriptase proteins share a common origin. Moreover, belpaoviruses, metaviruses, pseudoviruses, and retroviruses have other features in common. Their polymerase proteins are similar in structure and include aspartic protease (retroviral aspartyl protease) and an integrase belonging to the DDE recombinase superfamily (see Recombination-activating gene tructure. They also share similar capsid and nucleocapsid proteins/domains. Caulimoviruses also share some features with belpaoviruses, metaviruses, pseudoviruses, and retroviruses such as a homologous as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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. 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. Although retroviruses have different subfamilies, they have three basic groups: the oncoretroviruses (oncogenic retroviruses), the lentiviruses (slow retroviruses) and the spumaviruses (foamy viruses). The oncoretroviruses are able to cause cancer in some species, the lentivirus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudoviridae
''Pseudoviridae'' is a family of viruses, which includes three genera. Viruses of the family are actually LTR retrotransposons of the Ty1-copia family. They replicate via structures called virus-like particles (VLPs). VLPs are not infectious like normal virions, but they nevertheless make up an essential part of the pseudoviral lifecycle. Taxonomy ''Pseudoviridae'' is unofficially classified under group VI RNA Reverse Transcribing Viruses and infect fungi and invertebrates. ''Pseudoviridae'' comprises highly divergent members and most ''Pseudoviridae'' encode Gag and Pol on a single open reading frame. ''Pseudoviridae'' is included in the order ''Ortervirales'' along with families ''Belpaoviridae'', ''Metaviridae'', ''Retroviridae'', and ''Caulimoviridae''. The family includes the following genera: * '' Hemivirus'' * '' Pseudovirus'' * '' Sirevirus'' Further ''Pseudoviridae'' species not classified into a genus are: * ''Penicillium camemberti virus - GP1''NCBIPenicillium c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virus
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. 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,Dimmock p. 4 more than 9,000 virus species have been described in detail of the millions of types of viruses in the environment. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. 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 particles, or ''virions'', consisting of (i) the genetic material, i. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caulimoviridae
''Caulimoviridae'' is a family of viruses infecting plants. There are 94 species in this family, assigned to 11 genera. Viruses belonging to the family ''Caulimoviridae'' are termed double-stranded DNA (dsDNA) reverse-transcribing viruses (or pararetroviruses) i.e. viruses that contain a reverse transcription stage in their replication cycle. This family contains all plant viruses with a dsDNA genome that have a reverse transcribing phase in their lifecycle. Taxonomy The following genera are recognized: *'' Badnavirus'' *'' Caulimovirus'' *'' Cavemovirus'' *'' Dioscovirus'' *'' Petuvirus'' *'' Rosadnavirus'' *'' Ruflodivirus'' *'' Solendovirus'' *'' Soymovirus'' *'' Tungrovirus'' *'' Vaccinivirus'' Virus particle structure All viruses of this family are non-enveloped. Virus particles are either bacilliform or isometric. The type of nucleocapsid incorporated into the virus structure determines the size of the viral particles. Bacilliform particles are approximately 35–50 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capsid
A capsid is the protein shell of a virus, enclosing its genetic material. It consists of several oligomeric (repeating) structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or may not correspond to individual proteins, are called capsomeres. The proteins making up the capsid are called capsid proteins or viral coat proteins (VCP). The capsid and inner genome is called the nucleocapsid. Capsids are broadly classified according to their structure. The majority of the viruses have capsids with either helical or icosahedral structure. Some viruses, such as bacteriophages, have developed more complicated structures due to constraints of elasticity and electrostatics. The icosahedral shape, which has 20 equilateral triangular faces, approximates a sphere, while the helical shape resembles the shape of a spring, taking the space of a cylinder but not being a cylinder itself. The capsid faces may consist of one or more ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.gif "Click for more on -> Capsid")