Genetically engineered cattle could resist mad cow disease
Scientists at a South Dakota biotech company have genetically engineered cattle that appear to be resistant to mad cow disease, a paper published in the Monday issue of the journal Nature Biotechnology reports.
Although similar genetic engineering had been done in mice, this is the first time it has been accomplished in cattle.
The team of scientists first genetically engineered a line of cells in which the gene that produces the infectious proteins of mad cow disease — prions — was disabled. They then used those cells to clone 12 bulls so they were prevented from making the protein that, when "misfolded," causes prion diseases such as mad cow.
Those 12 bulls are now 2 years old and appear to be perfectly normal, says James Robl, president of Hematech Inc. in Sioux Falls, S.D., a biotech firm owned by the pharmaceutical division of Japanese brewing giant Kirin.
Although misfolded prions are not alive in the conventional sense, they can cause other proteins they come in contact with to misfold as well, creating the holes in the brain that characterize bovine spongiform encephalopathy (BSE, or spongy brain disease) in cattle and variant Creutzfeldt-Jakob disease in humans and other mammals.
When scientists took brain cells from the resistant cattle and mixed them with prions in a test tube, the brain cells did not misfold. Brain cells from normal cattle did. "That's a pretty good indication that they will not be able to contract the disease, nor would they be able to pass the disease on," Robl says.
Researchers injected mad cow-infected brain cells into the brains of some of the resistant cattle to see whether they develop the disease.
"In 11/2 years we'll have an answer," because prion diseases are so slow to develop, says Jürgen Richt, a co-author on the paper and veterinary microbiologist at the National Animal Disease Center in Ames, Iowa.
The bulls appear to be developmentally and reproductively normal and should be able to breed true, creating a line of mad cow-resistant cattle, Robl says. Because they are still adolescents, they have not yet been bred, but their semen appears to be normal.
The cattle are not meant for human consumption, Robl says. If they prove incapable of getting mad cow disease, they could be used to produce products important to industry, such as blood serum used in making pharmaceuticals and collagen for cosmetics. George Seidel, a reproduction technologies expert at Colorado State University in Fort Collins, calls the research "elegant," but with mad cow disease so rare in North America, it's more a niche market: "There are much easier ways … than to make transgenic cattle."
http://www.truthabouttrade.org/article.asp?id=6789
Scientists at a South Dakota biotech company have genetically engineered cattle that appear to be resistant to mad cow disease, a paper published in the Monday issue of the journal Nature Biotechnology reports.
Although similar genetic engineering had been done in mice, this is the first time it has been accomplished in cattle.
The team of scientists first genetically engineered a line of cells in which the gene that produces the infectious proteins of mad cow disease — prions — was disabled. They then used those cells to clone 12 bulls so they were prevented from making the protein that, when "misfolded," causes prion diseases such as mad cow.
Those 12 bulls are now 2 years old and appear to be perfectly normal, says James Robl, president of Hematech Inc. in Sioux Falls, S.D., a biotech firm owned by the pharmaceutical division of Japanese brewing giant Kirin.
Although misfolded prions are not alive in the conventional sense, they can cause other proteins they come in contact with to misfold as well, creating the holes in the brain that characterize bovine spongiform encephalopathy (BSE, or spongy brain disease) in cattle and variant Creutzfeldt-Jakob disease in humans and other mammals.
When scientists took brain cells from the resistant cattle and mixed them with prions in a test tube, the brain cells did not misfold. Brain cells from normal cattle did. "That's a pretty good indication that they will not be able to contract the disease, nor would they be able to pass the disease on," Robl says.
Researchers injected mad cow-infected brain cells into the brains of some of the resistant cattle to see whether they develop the disease.
"In 11/2 years we'll have an answer," because prion diseases are so slow to develop, says Jürgen Richt, a co-author on the paper and veterinary microbiologist at the National Animal Disease Center in Ames, Iowa.
The bulls appear to be developmentally and reproductively normal and should be able to breed true, creating a line of mad cow-resistant cattle, Robl says. Because they are still adolescents, they have not yet been bred, but their semen appears to be normal.
The cattle are not meant for human consumption, Robl says. If they prove incapable of getting mad cow disease, they could be used to produce products important to industry, such as blood serum used in making pharmaceuticals and collagen for cosmetics. George Seidel, a reproduction technologies expert at Colorado State University in Fort Collins, calls the research "elegant," but with mad cow disease so rare in North America, it's more a niche market: "There are much easier ways … than to make transgenic cattle."
http://www.truthabouttrade.org/article.asp?id=6789
