From Wikipedia,
the free encyclopedia.
The gene gun is a device
for injecting cells with
genetic information,
originally designed for
plant
transformation. The payload is
an
elemental particle of a
heavy metal coated with
plasmid
DNA. The actual name of the
gene gun is the Biolistic
Particle Delivery System, and
this technique is often simply
referred to as biolistics.
This device is able to
transform almost any plant and is
not limited to genetic material of
the nucleus: It can also transform
plastids.
Design
Helios Particle Delivery
System
The gene gun was originally a
nail gun for concrete surfaces
modified to fire
tungsten particles. Later the
design was greatly refined.
Improvements include the use of
helium propellant and a
multi-disk-collision delivery
mechanism. Other heavy metals such
as
gold and
silver are also used, but not
as frequently due to reasons of
availability and cost.
Conception of the gene gun is
accredited to
Edward Wolf and
Nelson Allen of the
Cornell Nanofabrication Facility
and
Cornell University plant
scientists
John Sanford and
Theodore Klein. The rights to
commercial use of the gene gun
were sold to
DuPont in
1990.
Application
The target of a gene gun is
often a
callus of undifferentiated
plant cells growing on gel medium
in a
petri dish. After the tungsten
particles have impacted the dish,
the gel and callus are largely
disrupted. However, some cells
were not obliterated in the
impact, and have successfully
enveloped a DNA coated tungsten
particle, whose DNA eventually
migrates to and integrates into a
plant
chromosome.
Cells from the entire petri
dish can be re-collected and
selected for successful
integration and expression of new
DNA using modern biochemical
techniques, such as a using a
tandem selectable gene and
northern blots.
Selected single cells from the
callus can be treated with a
series of plant hormones, such as
auxins and
gibberellins, and each may
divide and differentiate into the
organized, specialized, tissue
cells of an entire plant. This
capability of total re-generation
is called
totipotency. The new plant
that originated from a
successfully shot cell may have
new genetic (heritable) traits.
Using the gene gun may be
contrasted with using
Agrobacterium tumefaciens
and its Ti plasmid to insert
genetic information into plant
cells. See
transformation for different
methods of transformation in
different species.
