CaMV
Cauliflower Mosaic Virus
Cauliflower Mosaic Virus (CaMV) is the type member of the caulimoviruses,
one of the six genera in the Caulimoviridae family (see virus classification), pararetroviruses that infect plants (Pringle, 1999). Pararetroviruses replicate through reverse transcription just like retroviruses, but the viral particles contain DNA instead of RNA (Rothnie et al., 1994).
The human Hepatitis B virus (HBV) is the type member of the hepadnaviruses, animal infecting pararetroviruses (Nassal and Schaller, 1993; Seeger and Mason, 2000). However, concerning sequence and genestructure, plant and animal pararetroviruses are more distantly related to each other than to true retroviruses.
The CaMV particle is an icosahedron with a diameter of 52 nm built from 420
capsid protein (CP) subunits arranged with a triangulation T = 7, which
surrounds a solvent-filled central cavity (Cheng et al., 1992). It contains a
circular double-stranded DNA molecule of about 8.0 kB, interrupted by sitespecific discontinuities resulting from its replication by reverse transcription.
After entering the host, the single stranded nicks in the viral DNA are repaired, forming a supercoiled molecule that binds to histones. This DNA is translated into a full length, terminally redundant 35S RNA and a subgenomic 19S RNA.
ORF I Movement protein
ORF II Insect transmission factor
ORF III
ORF IV Capsid protein
ORF V Protease, reverse transcriptase and RNaseH
ORF VI Translational activator / Inclusion body protein
ORF VII Unknown (dispensable)