Description of Caulimoviridae
adapted from
ICTVdb
Virion Properties
Morphology
Virions consist of a
capsid. Virus capsid is not enveloped. Capsid is round to
elongated with icosahedral symmetry (T=7). The capsid is
isometric, or bacilliform and has a diameter of 35-50 nm. The
capsid shells of virions are composed of multiple layers. The
capsomer arrangement is not obvious. The bacilliform capsid has a
length of 130 nm, or 60-900 nm and a width of 24-30-35 nm.
Physicochemical and Physical Properties
Virions have a buoyant density in
CsCl of 1.3-1.312-1.4 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 200-251-285
S20w; of the
other(s) are 212
S20w. Isoelectric point pH is
4. The thermal inactivation point (TIP) is at 55-60-90°C.
The longevity
in vitro (LIV) is 1-28-85 days. Although the
titer is dependent on the host, the decimal exponent (DEX) of the
dilution end point is usually around 3-4. The infectivity is not
changed by treatment with ether; retained when deproteinized with
proteases, or decreased when deproteinized with proteases;
retained when deproteinized with phenol or detergent.
Nucleic Acid
The Mr of the genome constitutes 14.5-16.08-17% of
the virion by weight. The genome is not segmented and contains a
single molecule or two segments of open circular reverse
transcribing double-stranded DNA. Minor species of non-genomic
nucleic acid are not found in virions. The genome is sequenced,
and complete sequence is about 6800-7680-8300 nucleotides long.
The genome has a guanine + cytosine content of 28-35.5-43 %. The
genome has terminally redundant sequences. The terminally
redundant sequences have direct terminal repeats; are reiterated
internally in inverted form. The genome has single-stranded
discontinuities at specific sites; transcribed strand has one
discontinuity (or more, non-transcribed strand has one
discontinuity (or more). The genome has an intergenic poly (A)
region, or no intergenic poly (A) region.
Proteins
Proteins constitute about
83-84.41-85.9% of the particle weight.
The viral genome encodes structural proteins and
non-structural proteins. Virions consist of 1 structural
protein(s), or 3 structural protein(s).
Non-Structural Proteins: The virus codes for an
RNA-dependent DNA polymerase.
Lipids
Lipids are not reported.
Genome Organization and Replication
Transcription: The virus
codes for 2-8 ORF(s).
Sub-genomic RNA is present in infected cells.
Translation: The genome
replicates in the nucleus, or the cytoplasm. Replication involves