Description of Herpesviridae
adapted from
ICTVdb
Virion Properties
Morphology
Virions consist of an
envelope, a tegument, a nucleocapsid, and a core. Virus capsid is
enveloped. Virions are spherical to pleomorphic. Virions measure
120-200 nm in diameter. Surface projections are distinctive,
densely dispersed spikes that cover evenly the surface. Teguments
do not display a structure and proteins in variable amounts are
arranged sometimes in an asymmetric layer located between
envelope and capsid. Capsid/nucleocapsid is round and exhibits
icosahedral symmetry (T=16). The capsid is isometric and has a
diameter of 100-110 nm. Capsids appear hexagonal in outline. The
capsomer arrangement is clearly visible. The capsid consists of
162 capsomers with a hexagonal base and a hole running half-way
down the long axis. The core consists of a fibrillar spool on
which the DNA is wrapped. The end of the fibers are anchored to
the underside of the capsid shell.
Physicochemical and Physical Properties
Virions have a buoyant density in
CsCl of 1.15-1.29 g cm
-3.
Nucleic Acid
The genome is not segmented and contains a single
molecule of linear double-stranded DNA. The complete genome is
120000-220000 nucleotides long. The genome has a guanine +
cytosine content of 35-75 %.
Proteins
The viral genome encodes structural
proteins and non-structural proteins located in the envelope,
capsid, and tegument.
Structural Proteins: Internal lipid membrane
consists of several proteins.
Lipids
Lipids are present and located in the
envelope. The composition of viral lipids is not exactly known.
The lipids are of host origin and are derived from nuclear or
host cell membranes.