RNAi Engineering May Prevent Mad Cow

By "knocking down” the expression of disease-causing genes in a cloned goat fetus, researchers may have developed a way to prevent bovine spongiform encephalopathy (BSE), known as mad cow disease.

The researchers used genetic engineering to produce a goat cell line in which the gene encoding for prion protein (PrP) was targeted for silencing by RNA interference (RNAi). Cells from this line were then used for nuclear transfer to produce a transgenic goat fetus that showed a greater than 90% knock-down of PrP. In earlier studies, silencing the PrP gene in mice made them resistant to prion-mediated diseases, such as BSE. The results of the new research were published in the March 22 issue of the Proceedings of the [U.S.] National Academy of Sciences.

The same technology may be able to be used in cattle to prevent mad cow and other serious diseases, according to the researcher team, whose members are from Texas A&M's College of Veterinary Medicine & Biomedical Sciences (College Station, TX, USA) and the Howard Hughes Medical Institute's Cold Spring Harbor Laboratory (Cold Spring Harbor, NY, USA).

BSE is a fatal brain-wasting disease, first identified in 1986. It affects a cow's nervous system and causes the animal to lose much of its movement before it eventually dies. More than 180,000 cases of BSE have been confirmed worldwide, including recent cases in the United States. The disease can be passed to humans, and more than 100 such cases have been confirmed, most of those in the United Kingdom.

"The next step is to try and avoid the cloning process--to skip that process if possible in developing the disease-resistant animals,” explained Dr. Mark Westhusin, one of the researchers. "That's where more research is going to be needed and where the process goes from here.” Dr. Westhusin has been involved in several cloning "firsts,” including the cloning of a cat in 2002 and a white-tailed deer in 2004.



Related Links:
Texas A&M
HH Medical Institute's Cold Spring Harbor