Description of Comoviridae
adapted from
ICTVdb
Virion Properties
Morphology
Virions consist of a
capsid. Virus capsid is not enveloped, round with icosahedral
symmetry. The isometric capsid has a diameter of 28-30 nm. The
capsid consists of 32 capsomers. Virus preparations contain more
than one particle component.
Physicochemical and Physical Properties
Virions have a buoyant density in
CsCl of 1.28-1.5 g cm
-3.
Nucleic Acid
The genome is segmented; bipartite, segements are
distributed among 2 particle types of linear, positive-sense,
single-stranded RNA. The complete genome is 10000-15000
nucleotides long, is sequenced, complete sequence is about
6000-8000 nucleotides long, is sequenced, but only an estimate is
available, complete sequence is 4000-7000 nucleotides long.
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Description of Comoviridae
adapted from
ICTVdb
Virion Properties
Morphology
Virions consist of a
capsid. Virus capsid is not enveloped, round with icosahedral
symmetry. The isometric capsid has a diameter of 28-30 nm. The
capsid consists of 32 capsomers. Virus preparations contain more
than one particle component.
Physicochemical and Physical Properties
Virions have a buoyant density in
CsCl of 1.28-1.5 g cm
-3.
Nucleic Acid
The genome is segmented; bipartite, segements are
distributed among 2 particle types of linear, positive-sense,
single-stranded RNA. The complete genome is 10000-15000
nucleotides long, is sequenced, complete sequence is about
6000-8000 nucleotides long, is sequenced, but only an estimate is
available, complete sequence is 4000-7000 nucleotides long. The
5'-end of the genome has a genome-linked protein (VPg). The
3'-terminus has conserved nucleotide sequences. The 3'-terminus
has a poly (A) tract. The multipartite genome is divided among
different particles, each segment encapsidated separately and the
segments are distributed between 2 different types of particles.
The largest particles contain each one molecule of RNA-1
(sedimenting component B). The medium sized particles contain
each one molecule of RNA-2 (sedimenting component M). The
smallest particles contain no nucleic acid and are found in the
top (sedimenting component T) band after sedimentation.
Proteins
The viral genome encodes structural
proteins and non-structural proteins.
Lipids
Lipids are not reported.
Genome Organization and Replication
By itself, genomic nucleic acid is infectious.
Description of Sequiviridae
adapted from
ICTVdb Virion Properties
Morphology
Virions consist of a capsid. Virus capsid is not enveloped, round with polyhedral symmetry. The isometric capsid has a diameter of about 30 nm. Capsids appear round. The capsomer arrangement is not obvious.
Electron microscopic preparation and references: Virus preparation contains few virions.
Physicochemical and Physical Properties
Virions have a buoyant density in CsCl of 1.297-1.393-1.49 g cm
-3. There are 1 sedimenting component(s) found in purified preparations, or 2 sedimenting component(s) found in purified preparations. The sedimentation coefficient is 153-156-159
S20w; of the other(s) are 60
S20w. A
260/A
280 ratio is 1.46-1.597-1.67. The thermal inactivation point (TIP) is at 57.5-61.87-65°C. The longevity
in vitro (LIV) is 1-3.25-7 days. Although the titer is dependent on the host, the decimal exponent (DEX) of the dilution end point is usually around 3, or 4, or 5.
Nucleic Acid
The Mr of the genome constitutes 40% of the virion by weight. The genome is monopartite. Only one particle size of linear, positive-sense, single-stranded RNA is recovered. The genome is sequenced, and complete sequence is about 9000-12000 nucleotides long. The 5'-end of the genome has a probably genome-linked protein (VPg).
Proteins
The viral genome encodes structural proteins. Virions consist of 3 structural protein(s).
Lipids
Lipids are not reported.
Genome Organization and Replication
By itself, genomic nucleic acid is infectious (however, infectivity is protease-sensitive).