01/26/1994

Gene Gun Being Used in Auburn Research

AUBURN, Ala. - Taking aim at research has acquired a new meaning for Auburn University researchers who are using a special gun to explore new possibilities in genetic engineering.

The gun, known as a Gene Gun, uses .22 calibre bullets to incorporate genetic material into cell structures. The scope of its applications is broad, according to Henry Daniell, associate professor of molecular genetics in Auburn's Department of Botany and Microbiology.

Daniell is using this device to conduct Alabama Agricultural Experiment Station (AAES) studies aimed at enhancing the genetic characteristics of various crops.

Genetic engineering involves introducing foreign genes into plants or animals to impart economically important traits or to better understand the basic mechanisms of growth and development.

Through a U.S. Department of Agriculture-National Research Initiative Competitive Grant, Daniell has acquired a Gene Gun that he and other Auburn researchers are using to conduct a wide range of studies. AAES research areas include making crops more resistant to insects, herbicides, disease and salt or drought. The Gene Gun will be used on numerous crops, including peanuts, sweet potatoes, cowpeas, tobacco and mushrooms.

One area of interest to Daniell is the use of the Gene Gun in tobacco. He explained that plant material is now being used to make a biodegradable plastic, and he is working to enhance the production of protein-based polymers in tobacco plants for use in plastic production, replacing petroleum as the current source of plastic.

"In addition to applications in agricultural biotechnology, the Gene Gun is used in biomedical research," added Daniell.

He noted a hand-held version of the Gene Gun has been successfully used to correct genetic deficiencies in the livers of rats, which opens the door for human gene therapy. For example, physicians may be able to fire genes into an ailing organ that will overcome DNA mutations in the body. This type of therapy may prove useful in treating such health problems as ischemic heart disease, late onset diabetes, Parkinson's disease, Alzheimer's disease and aging, all of which are caused by alterations of the mitochondria DNA.

Daniell first encountered the Gene Gun while he was on the faculty at Harvard University and collaborating with researchers at Cornell University in New York. Researchers at Cornell invented it as a way to incorporate dye into pollen grains for genetic studies.

"It occurred to them that they might be able to use a gun to do something good for a change," laughed Daniell. "I used to tell them that one has to live in New York to think of this."

The device uses a bullet to propel genes (DNA) into the cell structure, though the bullet is simply the power behind the process. Tungsten or gold particles coated with foreign genes are put on the cylinder that is held in place by the pin loader. The cylinder is inserted into the barrel of the Gene Gun using the pin loader, and a .22 caliber bullet is then placed inside the barrel. When the bullet is fired, particles are accelerated into a chamber containing cells or tissues into which scientists want to incorporate foreign DNA. A stopping plate prevents the cylinder from striking the sample, but the tungsten particles and DNA forcefully enter into the cells.

"Until now, foreign genes have been introduced into cells in the nucleus. However, in crop plants many economically important traits are present inside subcellular compartments, such as chloroplasts and mitochondria," explained Daniell. For example, the gene for the protein conferring resistance to certain herbicides is encoded by genetic structures in the chloroplast, the area of a plant cell where photosynthesis occurs.

Another advantage of engineering foreign genes in this manner is that researchers can make genetic changes without using pollen. Daniell explained that when genes are transferred from one plant to another via pollen, genes from crop plants can be conferred to other plants, which can result in more persistent weeds. Introduction of foreign DNA into subcellular compartments using the gene gun precludes any escape of introduced foreign genes through pollen grains.

The Gene Gun has already been used to genetically engineer cereal crops, such as maize (corn), rice, wheat, and oats, as well as numerous dicotyledonous plants, such as soybean, tobacco and certain trees. In addition, the Gene Gun has been used to transform animals and fungi.

Many of the plant crops currently grown in Alabama are produced at or near their genetic potential. Other crops are limited because of pest or climatic problems. Gene manipulation is an efficient way to increase production without dramatically changing the current regulations or increasing the cost of production.

While this technology is new, the concept of genetic engineering has been used for generations. In the past, this has been accomplished through selective crossbreeding of animals or plants to enhance beneficial characteristics. This and other new genetic engineering technologies offer faster, more precise methods to achieve this goal.

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Office of Ag Communications & Marketing

Auburn University College of Agriculture
Alabama Agricultural Experiment Station
3 Comer Hall, Auburn University
Auburn, AL 36849
334-844-4877 (PHONE) 334-844-5892 (FAX)

Contact Jamie Creamer, 334-844-2783 or jcreamer@auburn.edu
Contact Katie Jackson, 334-844-5886 or smithcl@auburn.edu

01/26/94