Gene gun
In genetic engineering, a gene gun or biolistic particle delivery system is a device used to deliver exogenous DNA (transgenes), RNA, or protein to cells.
The original target was onions (chosen for their large cell size), and the device was used to deliver particles coated with a marker gene which would relay a signal if proper insertion of the DNA transcript occurred.
The early design was put into limited production by a Rumsey-Loomis (a local machine shop then at Mecklenburg Road in Ithaca, NY, USA).
Biolistics, Inc sold Dupont the rights to manufacture and distribute an updated device with improvements including the use of helium as a non-explosive propellant and a multi-disk collision delivery mechanism to minimize damage to sample tissues.
The target of a gene gun is often a callus of undifferentiated plant cells or a group of immature embryos growing on gel medium in a Petri dish.
[17] Biolistics has proven to be a versatile method of genetic modification and it is generally preferred to engineer transformation-resistant crops, such as cereals.
Thus the DNA may be transformed into whatever genomes are present in the cell, be they nuclear, mitochondrial, plasmid or any others, in any combination, though proper construct design may mitigate this.
The delivery and integration of multiple templates of the DNA construct is a distinct possibility, resulting in potential variable expression levels and copy numbers of the inserted gene.
- The gene gun apparatus is ready to fire.
- Helium fills the chamber and pressure builds against the rupture disk.
- The pressure eventually reaches the point where the rupture disk breaks, and the resulting burst of helium propels the DNA/gold-coated macrocarrier ('Plastic Disk') into the stopping screen.
- When the macrocarrier hits the stopping screen, the DNA-coated gold particles are propelled through the screen and into the target cells.