Bovine spongiform encephalopathy (BSE), or mad cow disease, is caused by prions, a misfolded "scrapie" form of the normal cellular protein, which is found on the surface of human, sheep, and cow neurons. Prion infections are also implicated in one form of the same disease in humans, called Variant Creutzfeldt-Jakob Disease, an incurable condition that causes neurologic abnormalities, dementia, and eventually death.
BSE has caused widespread public concern when it has appeared in cattle in Europe, Canada, and most recently the United States, as it is believed that the disease is transmitted across species by the consumption of prions from a diseased animal's central nervous system.
Unlike most infectious diseases, the infectious material of mad cow and other prion disease is not a virus, bacteria, or some other pathogen, but a protein. Normally, prion proteins are expressed throughout the body and sit anchored onto the surfaces of cells in a wide variety of tissues, particularly on cells in neuronal tissue. They are something of an enigma because scientists do not know what they do there. But if the function of prions is mysterious, their malfunction is notorious.
"The prion protein," says Scripps Research investigator Anthony Williamson, Ph.D., "has a Jekyll and Hyde personality."
A New View of Normal Prions
Previously, scientists viewed the normal cellular prion protein as mere fodder that the scrapie prions would turn into more scrapie prions until an army of scrapies grew into a spongy mass, killing brain cells, and causing the neurological wasting that characterizes the disease.
Now, Willi
'"/>
Contact: Jason Bardi
jasonb@scripps.edu
858-784-9254
Scripps Research Institute
29-Jan-2004