Rycina 34 Mykowirusy – wirusy infekujące grzyby J

''Pseudoviridae'' is a family of

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 Ivanovsk ...

es, which includes three genera. Viruses of the family are actually

LTR retrotransposons 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 in ...

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 ''Revtraviricetes'' is a class of viruses that contains all viruses that encode a reverse transcriptase. The group includes all ssRNA-RT viruses (including the retroviruses) and dsDNA-RT viruses. It is the sole class in the phylum ''Artvervirico ...

and infect

fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...

and

invertebrates Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordat ...

. ''Pseudoviridae'' comprises highly divergent members and most ''Pseudoviridae'' encode Gag and Pol on a single

open reading frame In molecular biology, open reading frames (ORFs) are defined as spans of DNA sequence between the start and stop codons. Usually, this is considered within a studied region of a prokaryotic DNA sequence, where only one of the six possible readin ...

. ''Pseudoviridae'' is included in the order ''Ortervirales'' along with families ''

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. Spec ...

'', ''

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, in ...

'', ''

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 ...

'', and ''

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 pa ...

''. The family includes the following genera: * '' Hemivirus'' * '' Pseudovirus'' * '' Sirevirus'' Further ''Pseudoviridae'' species not classified into a genus are: * ''Penicillium camemberti virus - GP1''NCBI
Penicillium camemberti virus - GP1
(species) * '' Phaseolus vulgaris Tpv2-6 virus''

Genome

Rycina 35 Mykowirusy – wirusy infekujące grzyby J

The

genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding g ...

of viruses from this family is unsegmented, -RT, positive-sense, single-stranded RNA and is 4200–9700

nucleotides Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules with ...

long. The genome encodes structural proteins and non-structural proteins which codes for an RNA-dependent DNA polymerase,

replicase RNA-dependent RNA polymerase (RdRp) or RNA replicase is an enzyme that catalyzes the replication of RNA from an RNA template. Specifically, it catalyzes synthesis of the RNA strand complementary to a given RNA template. This is in contrast to ...

, and reverse transcriptase for the reverse transcription step during replication.

Virology

The viral

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 ma ...

is unenveloped and looks roughly spherical. The capsid is round with icosahedral symmetry with triangulation number (T) = 3 and 4. It is also isometric to quasi-isometric and has a

diameter In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle. Both definitions are also valid fo ...

of 30-50 nm. LTR-

retrotransposons Retrotransposons (also called Class I transposable elements or transposons via RNA intermediates) are a type of genetic component that copy and paste themselves into different genomic locations ( transposon) by converting RNA back into DNA throug ...

are poorly characterized and

lipids Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include ...

have not reported. The genome integrates into the host genome and gets transcribed by host cell enzymes such as

eukaryotic Eukaryotes () are organisms whose Cell (biology), cells have a cell nucleus, nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the ...

nuclear

RNA polymerase II RNA polymerase II (RNAP II and Pol II) is a multiprotein complex that transcribes DNA into precursors of messenger RNA (mRNA) and most small nuclear RNA (snRNA) and microRNA. It is one of the three RNAP enzymes found in the nucleus of eukaryo ...

. Genome replication takes place in the host

cytoplasm In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. ...

, or the

nucleus Nucleus ( : nuclei) is a Latin word for the seed inside a fruit. It most often refers to: *Atomic nucleus, the very dense central region of an atom * Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA Nucl ...

and assembly can occur in the cytoplasm, or in the nucleus.

References

External links

ICTV Report: ''Pseudoviridae''Pseudoviridae
(Darwin Zoology) {{Taxonbar, from=Q3772842 RNA reverse-transcribing viruses Virus families Ortervirales