A decade after the discovery of viroids, Stanley Prusiner made the startling claim that scrapie, a neurodegener-ative disease of sheep, was caused by a self-replicating agent composed solely of protein. He called this type of entity a prion, and in the years which followed, other, related, diseases of humans and animals were shown to have a similar cause. These include bovine spongiform encephalopathy (BSE, 'mad cow disease') and its human equivalent, Creutzfeldt-Jakob disease.

How could something that contains no nucleic acid be capable of replicating itself? -Prusiner's idea seemed to go against the basic rules of biology. It appears that prions may be altered versions of normal animal proteins, and somehow have the ability to cause the normal version to refold itself into the mutant form. Thus the prion propagates itself. All prion diseases described thus far are similar conditions, involving a degeneration of brain tissue.

Was this article helpful?

0 0
Diabetes 2

Diabetes 2

Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...

Get My Free Ebook

Post a comment