Dependoparvovirus

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Dependoparvovirus
Adeno-associated viruses.jpg
Virus classification OOjs UI icon edit-ltr.svg
(unranked): Virus
Realm: Monodnaviria
Kingdom: Shotokuvirae
Phylum: Cossaviricota
Class: Quintoviricetes
Order: Piccovirales
Family: Parvoviridae
Subfamily: Parvovirinae
Genus:Dependoparvovirus
Species

See text

Dependoparvovirus (formerly Dependovirus or Adeno-associated virus group) is a genus in the subfamily Parvovirinae of the virus family Parvoviridae ; [1] [2] they are Group II viruses according to the Baltimore classification. Some dependoparvoviruses are also known as adeno-associated viruses because they cannot replicate productively in their host cell without the cell being coinfected by a helper virus such as an adenovirus, a herpesvirus, or a vaccinia virus.

Contents

Species

There are eleven recognized species: [3]

Virology

Schematic drawing of a virus particle of Dependoparvovirus (cross section and side view) ParvoviridaeVirion.jpg
Schematic drawing of a virus particle of Dependo­parvovirus (cross section and side view)

Dependoparvoviruses have an icosahedral shape, measure 22 nm [4] and are composed of 60 wedge-shaped proteins (triangulation number = 1). Three proteins (VP1, VP2 and VP3) are present in each capsomere. Each capsid is made from 5 VP1, 5 VP2, and 50 VP3 proteins. The capsid does not have an envelope. [5]

The genome is a single molecule of single stranded DNA with a length of 4.7 kilobases. It has only two open reading frames. The 3' open reading frame is the structural capsid protein, cap, which can be spliced to form two RNAs, one for virion protein 1 (VP1) and the other goes on to eventually make VP2 and VP3. The second gene, rep, can be spliced into four different, nonstructural, regulatory proteins that all aid in the genome replication. These proteins are named Rep 78, Rep68, Rep 52, and Rep 40 based on their molecular weight. [4]

Due to inverted terminal repeats (ITRs) at each end of the genome, a T-shaped secondary structure is formed. The complementary areas leave a 3' hydroxyl group single stranded for the replication to begin. This 3' hydroxyl group is used as a primer for the leading strand synthesis. Both positive and negative sense strands of DNA are made. Double stranded intermediates are formed throughout the replication; this means the two strands, positive and negative sense, will be matched up. [4] [5]

Host range

These viruses are capable of replication within all vertebrates. They are only limited by the virus they must infect with, also known as the helper virus. These helper viruses are necessary for the replication of a dependoparvovirus. A common helper virus in humans is the adenovirus.[ citation needed ]

Gene therapy

Dependoparvovirus is not infectious enough to trigger an immune response; this makes it a good virus to use as a gene therapy tool. Gene therapy is a possible treatment for a variety of disorders and diseases that are genetic in origin. Viral vectors are currently being developed to transport genes into human cells. Since this virus does not stimulate an immune response it can be used multiple times effectively without being neutralized before infection[ citation needed ] . Another reason these viruses are reliable vectors is the known insertion point for the genome. This virus always inserts its contents into the same place on chromosome 19.[ citation needed ] This predictability can cut down on the chances of inserting into an important area that might disrupt normal gene function or increase the risk of developing cancer. [6]

At this time, one challenge using this virus as a therapy tool is the fact that the genome is fairly small. With less than 5kb in the genome the amount of genetic material that can fit into the capsid is limited. Work is currently being done to increase the amount of information this vector can deliver. This may be accomplished by the ITRs found at both the 5' and 3' end of the genome. Since the ITRs have the same sequence they will leave complementary strands exposed if they are removed. The complementary strands can undergo recombination and join two 5kb inserted fragments together. [7]

Related Research Articles

<i>Parvoviridae</i> Family of viruses

Parvoviruses are a family of animal viruses that constitute the family Parvoviridae. They have linear, single-stranded DNA (ssDNA) genomes that typically contain two genes encoding for a replication initiator protein, called NS1, and the protein the viral capsid is made of. The coding portion of the genome is flanked by telomeres at each end that form into hairpin loops that are important during replication. Parvovirus virions are small compared to most viruses, at 23–28 nanometers in diameter, and contain the genome enclosed in an icosahedral capsid that has a rugged surface.

Coxsackie B4 virus are enteroviruses that belong to the Picornaviridae family. These viruses can be found worldwide. They are positive-sense, single-stranded, non-enveloped RNA viruses with icosahedral geometry. Coxsackieviruses have two groups, A and B, each associated with different diseases. Coxsackievirus group A is known for causing hand-foot-and-mouth diseases while Group B, which contains six serotypes, can cause a varying range of symptoms like gastrointestinal distress myocarditis. Coxsackievirus B4 has a cell tropism for natural killer cells and pancreatic islet cells. Infection can lead to beta cell apoptosis which increases the risk of insulitis.

<span class="mw-page-title-main">Picornavirus</span> Family of viruses

Picornaviruses are a group of related nonenveloped RNA viruses which infect vertebrates including fish, mammals, and birds. They are viruses that represent a large family of small, positive-sense, single-stranded RNA viruses with a 30 nm icosahedral capsid. The viruses in this family can cause a range of diseases including the common cold, poliomyelitis, meningitis, hepatitis, and paralysis.

<i>Geminiviridae</i> Family of viruses

Geminiviridae is a family of plant viruses that encode their genetic information on a circular genome of single-stranded (ss) DNA. There are 520 species in this family, assigned to 14 genera. Diseases associated with this family include: bright yellow mosaic, yellow mosaic, yellow mottle, leaf curling, stunting, streaks, reduced yields. They have single-stranded circular DNA genomes encoding genes that diverge in both directions from a virion strand origin of replication. According to the Baltimore classification they are considered class II viruses. It is the largest known family of single stranded DNA viruses.

<i>Birnaviridae</i> Family of viruses

Birnaviridae is a family of double-stranded RNA viruses. Salmonid fish, birds and insects serve as natural hosts. There are currently 11 species in this family, divided among seven genera. Diseases associated with this family include infectious pancreatic necrosis in salmonid fish, which causes significant losses to the aquaculture industry, with chronic infection in adult salmonid fish and acute viral disease in young salmonid fish.

<span class="mw-page-title-main">Adeno-associated virus</span> Species of virus

Adeno-associated viruses (AAV) are small viruses that infect humans and some other primate species. They belong to the genus Dependoparvovirus, which in turn belongs to the family Parvoviridae. They are small replication-defective, nonenveloped viruses and have linear single-stranded DNA (ssDNA) genome of approximately 4.8 kilobases (kb).

<i>Aphthovirus</i> Genus of viruses

Aphthovirus is a viral genus of the family Picornaviridae. Aphthoviruses infect split-hooved animals, and include the causative agent of foot-and-mouth disease, Foot-and-mouth disease virus (FMDV). There are seven FMDV serotypes: A, O, C, SAT 1, SAT 2, SAT 3 and Asia 1, and four non-FMDV serotypes belonging to three additional species Bovine rhinitis A virus (BRAV), Bovine rhinitis B virus (BRBV) and Equine rhinitis A virus (ERAV).

A helper dependent virus, also termed a gutless virus, is a synthetic viral vector dependent on the assistance of a helper virus in order to replicate, and can be used for purposes such as gene therapy. Naturally-occurring satellite viruses are also helper virus dependent, and can sometimes be modified to become viral vectors.

Gyrovirus is a genus of viruses, in the family Anelloviridae. Until 2011, chicken anemia virus was the only Gyrovirus identified, but since then gyroviruses have also been identified in humans. Diseases associated with this genus include: chicken infectious anemia, which is associated with depletion of cortical thymocytes and erythroblastoid cells.

<span class="mw-page-title-main">Double-stranded RNA viruses</span> Type of virus according to Baltimore classification

Double-stranded RNA viruses are a polyphyletic group of viruses that have double-stranded genomes made of ribonucleic acid. The double-stranded genome is used as a template by the viral RNA-dependent RNA polymerase (RdRp) to transcribe a positive-strand RNA functioning as messenger RNA (mRNA) for the host cell's ribosomes, which translate it into viral proteins. The positive-strand RNA can also be replicated by the RdRp to create a new double-stranded viral genome.

Human bocavirus (HBoV) is the name given to all viruses in the genus Bocaparvovirus of virus family Parvoviridae that are known to infect humans. HBoV1 and HBoV3 are members of species Primate bocaparvovirus 1 whereas viruses HBoV2 and HBoV4 belong to species Primate bocaparvovirus 2. Some of these viruses cause human disease. HBoV1 is strongly implicated in causing some cases of lower respiratory tract infection, especially in young children, and several of the viruses have been linked to gastroenteritis, although the full clinical role of this emerging infectious disease remains to be elucidated.

<span class="mw-page-title-main">Iflaviridae</span> Family of viruses

Iflaviridae is a family of positive sense RNA viruses insect-infecting viruses. Some of the insects commonly infected by iflaviruses include aphids, leafhoppers, flies, bees, ants, silkworms and wasps. The name "Ifla" is derived from the name "Infectious flacherie virus", a member species. There is one genus (Iflavirus) and 16 species in this family.

Densovirinae is a subfamily of single-stranded DNA viruses in the family Parvoviridae. The subfamily has 11 recognized genera and 21 species. Densoviruses are known to infect members of insect orders Blattodea, Diptera, Hemiptera, Hymenoptera, Lepidoptera, and Orthoptera, while some viruses infect and multiply in crustaceans such as shrimp or crayfish, or sea stars from phylum Echinodermata.

<i>Bidensovirus</i> Genus of viruses

Bidensovirus is a genus of single stranded DNA viruses that infect invertebrates. The species in this genus were originally classified in the family Parvoviridae but were moved to a new genus because of significant differences in the genomes.

Self-complementary adeno-associated virus (scAAV) is a viral vector engineered from the naturally occurring adeno-associated virus (AAV) to be used as a tool for gene therapy. Use of recombinant AAV (rAAV) has been successful in clinical trials addressing a variety of diseases. This lab-made progeny of rAAV is termed "self-complementary" because the coding region has been designed to form an intra-molecular double-stranded DNA template. A rate-limiting step for the standard AAV genome involves the second-strand synthesis since the typical AAV genome is a single-stranded DNA template. However, this is not the case for scAAV genomes. Upon infection, rather than waiting for cell mediated synthesis of the second strand, the two complementary halves of scAAV will associate to form one double stranded DNA (dsDNA) unit that is ready for immediate replication and transcription. The caveat of this construct is that instead of the full coding capacity found in rAAV (4.7–6kb) scAAV can only hold about half of that amount (≈2.4kb).

<span class="mw-page-title-main">Major capsid protein VP1</span>

Major capsid protein VP1 is a viral protein that is the main component of the polyomavirus capsid. VP1 monomers are generally around 350 amino acids long and are capable of self-assembly into an icosahedral structure consisting of 360 VP1 molecules organized into 72 pentamers. VP1 molecules possess a surface binding site that interacts with sialic acids attached to glycans, including some gangliosides, on the surfaces of cells to initiate the process of viral infection. The VP1 protein, along with capsid components VP2 and VP3, is expressed from the "late region" of the circular viral genome.

<i>Protoparvovirus</i> Genus of viruses

Protoparvovirus is a genus of viruses in the Parvovirinae subfamily of the virus family Parvoviridae. Vertebrates serve as natural hosts. There are 15 species in the genus including Rodent protoparvovirus 1 for which the exemplar virus is minute virus of mice (MVM). This genus also includes canine parvovirus (CPV), which causes gastrointestinal tract damage in puppies that is about 80% fatal, and porcine parvovirus (PPV), which is a major cause of fetal death and infertility in pigs. The genus divides phylogenetically into two branches, one that contains many founder members of the family, such as MVM, CPV and PPV, which have been studied in considerable detail, and a second branch occupied exclusively by predicted viruses whose coding sequences were identified recently in the wild using virus discovery approaches, but whose biology remains minimally explored. This second branch currently contains two species whose members infect humans, called Primate protoparvovirus 1 and Primate protoparvovirus 3. Until 2014, the genus was called Parvovirus, but it was renamed to eliminate confusion between members of this genus and members of the entire family Parvoviridae.

<i>Avibirnavirus</i> Genus of viruses

Avibirnavirus is a genus of viruses in family Birnaviridae. There is a single species in this genus: Infectious bursal disease virus, which infects chickens and other fowl. It causes severe inflammation of the bursa of Fabricius, and causes considerable morbidity and mortality.

Triatoma virus (TrV) is a virus belonging to the insect virus family Dicistroviridae. Within this family, there are currently 3 genera and 15 species of virus. Triatoma virus belongs to the genus Cripavirus. It is non-enveloped and its genetic material is positive-sense, single-stranded RNA. The natural hosts of triatoma virus are invertebrates. TrV is a known pathogen to Triatoma infestans, the major vector of Chagas disease in Argentina which makes triatoma virus a major candidate for biological vector control as opposed to chemical insecticides. Triatoma virus was first discovered in 1984 when a survey of pathogens of triatomes was conducted in the hopes of finding potential biological control methods for T. infestans.

<i>Monodnaviria</i> Realm of viruses

Monodnaviria is a realm of viruses that includes all single-stranded DNA viruses that encode an endonuclease of the HUH superfamily that initiates rolling circle replication of the circular viral genome. Viruses descended from such viruses are also included in the realm, including certain linear single-stranded DNA (ssDNA) viruses and circular double-stranded DNA (dsDNA) viruses. These atypical members typically replicate through means other than rolling circle replication.

References

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  3. "Virus Taxonomy: 2020 Release". International Committee on Taxonomy of Viruses (ICTV). March 2021. Retrieved 10 May 2021.
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  5. 1 2 ICTVdB Management (2006). Büchen- Osmond, C. (ed.). "ICTVdB - The Universal Virus Database, version 4: Dependovirus". Columbia University, New York, US. Retrieved 4 May 2009.
  6. Excoffon, K; et al. (2009). "Directed evolution of adeno-associated virus to an infectious respiratory virus". Proceedings of the National Academy of Sciences. 106 (10): 3865–3870. Bibcode:2009PNAS..106.3865E. doi: 10.1073/pnas.0813365106 . PMC   2646629 . PMID   19237554.
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