Cowpea mosaic virus (CPMV) is a non-enveloped
plant virus of the
comovirus group. Infection of a susceptible
cowpea
The cowpea (''Vigna unguiculata'') is an annual herbaceous legume from the genus '' Vigna''. Its tolerance for sandy soil and low rainfall have made it an important crop in the semiarid regions across Africa and Asia. It requires very few inpu ...
leaf
A leaf (: leaves) is a principal appendage of the plant stem, stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leav ...
causes a "mosaic"
pattern in the leaf, and results in high virus yields (1-2 g/kg). Its
genome
A genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding genes, other functional regions of the genome such as ...
consists of 2 molecules of
positive-sense RNA
Ribonucleic acid (RNA) is a polymeric molecule that is essential for most biological functions, either by performing the function itself (non-coding RNA) or by forming a template for the production of proteins (messenger RNA). RNA and deoxyrib ...
(RNA-1 and RNA-2) which are separately encapsidated. Both RNA1 and RNA2 have a
VPg (virus genome-linked protein) at the 5'end, and
polyadenylation
Polyadenylation is the addition of a poly(A) tail to an RNA transcript, typically a messenger RNA (mRNA). The poly(A) tail consists of multiple adenosine monophosphates; in other words, it is a stretch of RNA that has only adenine bases. In euka ...
at the 3' end. Genomic RNA1 and RNA2 are expressed by a polyprotein processing strategy. RNA1 encodes
helicase
Helicases are a class of enzymes that are vital to all organisms. Their main function is to unpack an organism's genetic material. Helicases are motor proteins that move directionally along a nucleic double helix, separating the two hybridized ...
, VPg,
protease
A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalysis, catalyzes proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the formation of new protein products ...
and
RdRp. RNA2 encodes
movement protein and
coat protein. The virus particles are 28 nm in diameter and contain 60 copies each of a Large (L) and Small (S) coat protein. The structure is well characterised to atomic resolution, and the viral particles are thermostable. The identification of the virus is attributed to Lister and Thresh in 1955, but it is now known as a variant of the
Sunn-hemp mosaic virus.
CPMV displays a number of features that can be exploited for
nanoscale biomaterial
fabrication. Its
genetic, biological and physical properties are well characterised, and it can be isolated readily from plants. There are many stable mutants already prepared that allow specific modification of the
capsid
A capsid is the protein shell of a virus, enclosing its genetic material. It consists of several oligomeric (repeating) structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or m ...
surface. It is possible to attach a number of different chemicals to the virus surface and to construct multilayer
arrays of such
nanoparticle
A nanoparticle or ultrafine particle is a particle of matter 1 to 100 nanometres (nm) in diameter. The term is sometimes used for larger particles, up to 500 nm, or fibers and tubes that are less than 100 nm in only two directions. At ...
s on solid surfaces. This gives the natural or genetically engineered nanoparticles a range of properties which could be useful in nanotechnological applications such as
biosensor
A biosensor is an analytical device, used for the detection of a chemical substance, that combines a biological component with a physicochemical detector.
The ''sensitive biological element'', e.g. tissue, microorganisms, organelles, cell rece ...
s,
catalysis
Catalysis () is the increase in rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quick ...
and nanoelectronic devices.
One example use of CPMV particles is to amplify signals in
microarray
A microarray is a multiplex (assay), multiplex lab-on-a-chip. Its purpose is to simultaneously detect the expression of thousands of biological interactions. It is a two-dimensional array on a Substrate (materials science), solid substrate—usu ...
based sensors. In this application, the virus particles separate the
fluorescent dye
Juan de Guillebon, better known by his stage name DyE, is a French musician. He is known for the music video of the single "Fantasy
Fantasy is a genre of speculative fiction that involves supernatural or Magic (supernatural), magical ele ...
s used for signaling in order to prevent the formation of non-fluorescent
dimers that act as
quenchers. Another example is the use of CPMV as a nanoscale
breadboard
A breadboard, solderless breadboard, or protoboard is a construction base used to build semi-permanent prototypes of electronic circuits. Unlike a perfboard or stripboard, breadboards do not require soldering or destruction of tracks and are h ...
for molecular electronics.
CPMV particles have also shown potential for in-situ vaccination in cancer immunotherapy
References
External links
Separation and recovery of intact gold-virus complexby
agarose gel electrophoresis and
electroelution: Application to the purification of cowpea mosaic virus and colloidal gold complex
ICTVdB—The Universal Virus Database: Cowpea mosaic virus
*ICTV Virus Taxonomy 200
UniProt Taxonomy
{{DEFAULTSORT:Cowpea Mosaic Virus
Comoviruses
Viral plant pathogens and diseases