Viroids
Lyndsay Murrow
BMS 265
Nomenclature
Viroid =
“virus- like”
Adapted from Flores R et al (1998) Arch Virol 143, 623-629.
Discovery
Early 1960s:
1968:
1973: Electron
1976: EM
Raymer and
O’Brien develop a
bioassay for the
agent causing
potato spindle
tuber disease
Characterization of
chrysanthemum
stunt and citrus
exocortis as nontypical viruses
micrograph shows
viroid’s hairpin
structure
shows that
viroids form
closed circular
RNAs
1965: Raymer
1971: Diener
1974:
1978: PSTVd is
teams up with
Diener; they show
that agent is not a
typical virion
demonstrates that
the agent is a free
non-coding RNA,
coins the term
viroid
Confirmation that
viroids are noncoding
sequenced
Example Members
Genus Pospiviroids:
Genus Coleviroids:
PSTVd (potato spindle tuber)
CbVd 1 (coleus blumei 1)
Genus Hostuviroids:
Genus Avsunviroids:
HSVd (hop stunt)
ASBVd (avocado sunblotch)
Genus Cocadviroids:
Genus Pelamoviroids:
CCCVd (coconut cadang-cadang)
PLMVd (peach latent mosaic)
Genus Apscaviroids:
ASSVd (apple scar skin)
Pospiviroidae: Nuclear, CCR, no
hammerhead self-cleavage
Avsunviroidae: Chloroplastic, no CCR,
hammerhead self-cleavage
Evolution and Conservation
William G. Scott
Diener TO (1996) Virus Genes 11, 119-131.
Biogenesis
Adapted from Daròs J et al (2006) EMBO Reports 7, 593-598.
Cellular Functions (Pathogenicity)
Pray LA (2004) The Scientist 18, 23.
Mechanism of Action
Martick M and Scott WG (2006) SSRL Research Highlight 11, 119-131.
http://ssrl.slac.stanford.edu/research/highlights_archive/ribozyme.html
http://rnaworld.bio.ku.edu
Potential as a Tool
Citti L and Rainaldi G (2005) Curr Gene Ther 5, 11-24.