''Mastadenovirus'' is a genus of
viruses
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 1 ...
in the family ''
Adenoviridae
Adenoviruses (members of the family ''Adenoviridae'') are medium-sized (90–100 nm), nonenveloped (without an outer lipid bilayer) viruses with an icosahedral nucleocapsid containing a double-stranded DNA genome. Their name derives from the ...
''. Humans and other mammals serve as natural hosts. There are 51 species in this genus. The genus as a whole includes many very common causes of human infection, estimated to be responsible for 2 to 5% of all respiratory infections, as well as gastrointestinal and eye infections. Symptoms are usually mild.
Specific tropisms include: serotypes 3, 5, and 7: lower respiratory tract infections, serotypes 8, 19, and 37: epidemic keratoconjunctivitis, serotypes 4 and 7: acute respiratory disease, serotypes 40 and
41: gastroenteritis, serotype 14: can cause potentially fatal adenovirus infections.
Canine mastadenovirus A (formerly canine adenovirus-1, CAdV-1) can lead to death in puppies, or encephalitis in other carnivore species.
Etymology
The name ''Mastadenovirus'' is derived from the Greek word ''mastos'' '
breast
The breast is one of two prominences located on the upper ventral region of a primate's torso. Both females and males develop breasts from the same embryological tissues.
In females, it serves as the mammary gland, which produces and secret ...
' (hence ''mammal'') and ''adenovirus'', named for the human
adenoid
In anatomy, the adenoid, also known as the pharyngeal tonsil or nasopharyngeal tonsil, is the superior-most of the tonsils. It is a mass of lymphatic tissue located behind the nasal cavity, in the roof of the nasopharynx, where the nose blends ...
s, which the virus was first isolated from.
Taxonomy
The genus contains the following species:
* ''
Bat mastadenovirus A''
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Bat mastadenovirus B''
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Bat mastadenovirus C''
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Bat mastadenovirus D''
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Bat mastadenovirus E''
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Bat mastadenovirus F''
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Bat mastadenovirus G''
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Bat mastadenovirus H''
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Bat mastadenovirus I''
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Bat mastadenovirus J''
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Bovine mastadenovirus A''
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Bovine mastadenovirus B''
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Bovine mastadenovirus C''
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Canine mastadenovirus A''
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Deer mastadenovirus B''
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Dolphin mastadenovirus A''
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Dolphin mastadenovirus B''
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Equine mastadenovirus A''
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Equine mastadenovirus B''
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Guinea pig mastadenovirus A''
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Human mastadenovirus A''
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Human mastadenovirus B''
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Human mastadenovirus C''
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Human mastadenovirus D''
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Human mastadenovirus E''
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Human mastadenovirus F''
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Human mastadenovirus G''
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Murine mastadenovirus A''
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Murine mastadenovirus B''
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Murine mastadenovirus C''
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Ovine mastadenovirus A''
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Ovine mastadenovirus B''
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Ovine mastadenovirus C''
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Platyrrhini mastadenovirus A''
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Polar bear mastadenovirus A''
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Porcine mastadenovirus A''
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Porcine mastadenovirus B''
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Porcine mastadenovirus C''
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Sea lion mastadenovirus A''
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Simian mastadenovirus A''
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Simian mastadenovirus B''
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Simian mastadenovirus C''
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Simian mastadenovirus D''
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Simian mastadenovirus E''
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Simian mastadenovirus F''
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Simian mastadenovirus G''
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Simian mastadenovirus H''
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Simian mastadenovirus I''
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Skunk mastadenovirus A''
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Squirrel mastadenovirus A''
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Tree shrew mastadenovirus A''
Human serotypes
Structure
Viruses in ''Mastadenovirus'' are
non-enveloped, with
icosahedral
In geometry, an icosahedron ( or ) is a polyhedron with 20 faces. The name comes and . The plural can be either "icosahedra" () or "icosahedrons".
There are infinitely many non- similar shapes of icosahedra, some of them being more symmetrica ...
geometries, and T=25 symmetry. The diameter is around 90 nm. Genomes are linear and non-segmented, around 35-36kb in length. The genome codes for 40 proteins.
Life cycle
Viral replication is nuclear. Entry into the host cell is achieved by attachment of the viral fibers to the host CAR adhesion receptor. Subsequent binding of the penton protein to host integrin entry receptors mediates internalization into the host cell by clathrin-mediated endocytosis
Receptor-mediated endocytosis (RME), also called clathrin-mediated endocytosis, is a process by which cells absorb metabolites, hormones, proteins – and in some cases viruses – by the inward budding of the plasma membrane (invagination). This ...
of the virus and fiber shedding. Some serotypes also seem to use macropinocytosis. Disruption of host endosomal membrane by lytic protein VI releases 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 ...
in the cytosol. Microtubular transport toward nucleus of the viral genome still protected by the core protein VII and a partial capsid mainly composed of hexons and protein IX. Docking at the NPC and capsid disruption. Import of the viral genome into host nucleus mediated by core protein VII. Transcription of early genes (E genes) by host RNA pol II: these proteins optimize the cellular milieu for viral replication, and counteract a variety of antiviral defenses. Intermediate genes activate replication of the DNA genome by DNA strand displacement in the nucleus. Expression of L4-22K and L4-33K causes early to late switch. Transcription of late genes (L genes) by host RNA pol II, mostly encoding structural proteins. Host translation shutoff performed by the viral 100K protein. Assembly of new virion
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 1 ...
s in the nucleus. Virions are released by lysis of the cell. Virion maturation by the viral proteasehost receptors, which mediates clathrin-mediated endocytosis. Replication follows the DNA strand displacement model. DNA-templated transcription, with some alternative splicing mechanism is the method of transcription. Translation takes place by ribosomal shunting Ribosome shunting is a mechanism of translation initiation in which ribosomes bypass, or "shunt over", parts of the 5' untranslated region to reach the start codon. However, a benefit of ribosomal shunting is that it can translate backwards allowi ...
. The virus exits the host cell by nuclear envelope breakdown, viroporin
Viroporins are small and usually hydrophobic multifunctional viral proteins that modify cellular membranes, thereby facilitating virus release from infected cells. Viroporins are capable of assembling into oligomeric ion channels or pores in the h ...
s, and lysis.
Human, mammals, and vertebrates serve as the natural host. Transmission routes are fecal-oral and respiratory.
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References
External links
Viralzone: Mastadenovirus
ICTV
{{Taxonbar, from=Q1907818
Adenoviridae
Virus genera