Biology Reference
In-Depth Information
CPV naturally infects canine cells using the transferrin receptor (Parker
et al
., 2001). Transferrin is a circulatory iron carrier protein that is in great
demand, particularly during cellular growth and proliferation; transferrin
receptors are upregulated on cancer cells. The natural receptor specificity of
CPV has been exploited for biomedical nanotechnology (discussed in Chapter
8). A pilot study demonstrated that CPV particles are naturally targeted to and
internalized by various mammalian tumor cells
in vitro
(Singh
et al
., 2006).
2.3 ROD-SHAPED VNPs
..1
Potato Virus X
: A Plant Virus
PVX is the type member of the potexvirus group (Koenig & Lesemann,
1989). The particles are flexible rods with dimensions of 515 nm by 13 nm,
and consist of 1270 identical coat protein subunits (Kendall
., 2008).
PVX can be found worldwide in areas where potatoes are grown. Natural
hosts are members of the family
et al
(tobacco)
plants are also susceptible to mechanical inoculation to produce particles in
gram quantities from 1 kg infected leaf material. Infectious cDNA clones of
PVX genomic RNA are available, and genetic modifications protocols have
been established (Baulcombe
Solanaceae
, and
N
.
benthamiana
., 1995). PVX has been used for epitope
presentation strategies for vaccine development (Uhde
et al
et al
., 2005; Uhde-
Holzem
., 2007) and recently also received attention as a VNP platform
for materials science (Carette
et al
et al
., 2007) and medicine (Steinmetz
et al
.,
2009) (see Chapters 4, 7, and 8).
..
Tobacco Mosaic Virus
: A Plant Virus
TMV is a rod-shaped tobamovirus. TMV is distributed worldwide and has a
broad host range. TMV is transmitted by mechanical contact between plants
and man. The particles can be produced in high titers in
Nicotiana tabacum
or N. benthamiana
plants; yields of up to 2 g/kg infected leaf material can be
obtained.
TMV particles contain a single-stranded, positive-sense RNA genome.
The capsid is a straight, rigid, tubular structure with dimensions of 18 by
300 nm. It is composed of approximately 2130 identical protein subunits
closely packed in a helix with a pitch of 2.3 nm and 16 1/3 subunits per turn
(Fig. 2.7). The X-ray structure of the particles has been determined (Namba
& Stubbs, 1986). The self-assembly of the TMV rod has been extensively
studied (Culver, 2002).
assembly and disassembly methods have been
established and are exploited for various nanotechnological applications.
In vitro
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