Pseudoviridae
Encyclopedia
The Pseudoviridae are a family of virus
es, including the following genera:
The type species Saccharomyces cerevisiae
Ty1 virus, from the genus
pseudovirus and the type species Drosophila melanogaster
copia virus from the genus Hemivirus, both belong to the Pseudoviridae family. The Hemivirus and Pseudovirus constitute the two genera of Pseudoviridae.
Pseudoviridae is classified under group VI RNA
Reverse Transcribing Viruses and infect fungi and invertebrates. The genome
of viruses from this family is unsegmented, -RT, positive-sense, single-stranded RNA and is 4200-9700 nucleotides long. The genome encodes structural proteins and non-structural proteins which codes for an RNA-dependent DNA polymerase
, replicase, and reverse transcriptase
for the reverse transcription step during replication
.
Its genome integrates into the host genome and gets transcribed by host cell enzymes such as eukaryotic nuclear RNA polymerase II
. Genome replication
takes place in the host cytoplasm
, or the nucleus
and assembly can occur in the cytoplasm, or in the nucleus.The viral capsid
is unenveloped and looks roughly spherical. The capsid is round with icosahedral symmetry (T=3 and 4), and is also isometric
to quasi-isometric and has a diameter
of 30-50 nm. LTR- retrotransposons are poorly characterized and lipids are not reported
Pseudoviridae comprises highly divergent members and most Pseudoviridae encode Gag and Pol on a single open reading frame
.
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
es, including the following genera:
- Genus Pseudovirus; type species: Saccharomyces cerevisiae Ty1 virus
- Genus Hemivirus; type species: Drosophila melanogaster copia virus
The type species Saccharomyces cerevisiae
Saccharomyces cerevisiae
Saccharomyces cerevisiae is a species of yeast. It is perhaps the most useful yeast, having been instrumental to baking and brewing since ancient times. It is believed that it was originally isolated from the skin of grapes...
Ty1 virus, from the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
pseudovirus and the type species Drosophila melanogaster
Drosophila melanogaster
Drosophila melanogaster is a species of Diptera, or the order of flies, in the family Drosophilidae. The species is known generally as the common fruit fly or vinegar fly. Starting from Charles W...
copia virus from the genus Hemivirus, both belong to the Pseudoviridae family. The Hemivirus and Pseudovirus constitute the two genera of Pseudoviridae.
Pseudoviridae is classified under group VI RNA
RNA
Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....
Reverse Transcribing Viruses and infect fungi and invertebrates. The genome
Genome
In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....
of viruses from this family is unsegmented, -RT, positive-sense, single-stranded RNA and is 4200-9700 nucleotides long. The genome encodes structural proteins and non-structural proteins which codes for an RNA-dependent DNA polymerase
DNA polymerase
A DNA polymerase is an enzyme that helps catalyze in the polymerization of deoxyribonucleotides into a DNA strand. DNA polymerases are best known for their feedback role in DNA replication, in which the polymerase "reads" an intact DNA strand as a template and uses it to synthesize the new strand....
, replicase, and reverse transcriptase
Reverse transcriptase
In the fields of molecular biology and biochemistry, a reverse transcriptase, also known as RNA-dependent DNA polymerase, is a DNA polymerase enzyme that transcribes single-stranded RNA into single-stranded DNA. It also helps in the formation of a double helix DNA once the RNA has been reverse...
for the reverse transcription step during replication
DNA replication
DNA replication is a biological process that occurs in all living organisms and copies their DNA; it is the basis for biological inheritance. The process starts with one double-stranded DNA molecule and produces two identical copies of the molecule...
.
Its genome integrates into the host genome and gets transcribed by host cell enzymes such as eukaryotic nuclear RNA polymerase II
RNA polymerase II
RNA polymerase II is an enzyme found in eukaryotic cells. It catalyzes the transcription of DNA to synthesize precursors of mRNA and most snRNA and microRNA. A 550 kDa complex of 12 subunits, RNAP II is the most studied type of RNA polymerase...
. Genome replication
Replication
Replication may refer to:Science* Replication is one of the main principles of the scientific method, a.k.a. reproducibility** Replication , the repetition of a test or complete experiment...
takes place in the host cytoplasm
Cytoplasm
The cytoplasm is a small gel-like substance residing between the cell membrane holding all the cell's internal sub-structures , except for the nucleus. All the contents of the cells of prokaryote organisms are contained within the cytoplasm...
, or the nucleus
Cell nucleus
In cell biology, the nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these...
and assembly can occur in the cytoplasm, or in the nucleus.The viral capsid
Capsid
A capsid is the protein shell of a virus. It consists of several oligomeric 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 capsid encloses the genetic...
is unenveloped and looks roughly spherical. The capsid is round with icosahedral symmetry (T=3 and 4), and is also isometric
Isometric
The term isometric comes from the Greek for "having equal measurement".isometric may mean:* Isometric projection , a method for the visual representation of three-dimensional objects in two dimensions; a form of orthographic projection, or more specifically, an axonometric projection.* Isometry and...
to quasi-isometric and has a diameter
Diameter
In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints are on the circle. The diameters are the longest chords of the circle...
of 30-50 nm. LTR- retrotransposons are poorly characterized and lipids are not reported
Pseudoviridae comprises highly divergent members and most Pseudoviridae encode Gag and Pol on a single open reading frame
Open reading frame
In molecular genetics, an open reading frame is a DNA sequence that does not contain a stop codon in a given reading frame.Normally, inserts which interrupt the reading frame of a subsequent region after the start codon cause frameshift mutation of the sequence and dislocate the sequences for stop...
.