Scientists Closer to Understanding Prion Disease
Date: 16-Oct-03
Country: UK
Bovine spongiform encephalopathy (BSE) or mad cow disease, and its human equivalent, variant Creutzfeldt-Jakob disease (vCJD), are incurable, degenerative brain disorders caused by proteins called prions.
Scientists had been puzzled about how prions replicate because they do not have RNA or DNA, the nucleic acids that carry the genetic instructions to build proteins in living organisms or viruses.
But researchers at Dartmouth Medical School in New Hampshire have discovered that RNA may be the trigger that changes the harmless prions into rogue infectious agents.
"It has been well proven that nucleic acids, including RNA, are not part of the infectious agent, so it's an ironic twist that a catalyst for the reaction may be RNA," Dr Surachai Supattapone, a member of the research team, said in a statement yesterday.
The study was published in the journal Nature.
In laboratory studies the scientists discovered that prions need specific RNA molecules to transform themselves.
"This stimulatory RNA appears to be a specific one, which makes it exciting to study. If we can identify, clone and produce this specific RNA, it may be useful as a therapeutic target or diagnostic tool," Supattapone explained.
The RNA link could help doctors spot the disease earlier before it causes permanent brain damage.
In a separate study, also reported in Nature, Adriano Aguzzi and colleagues at Zurich University described how the rogue protein may enter the brain.
British scientists first identified vCJD and its link to eating meat infected with BSE in 1996. There is no cure for the illness or other prion diseases.
The incubation period, before signs of the illness are evident, can be a decade or more. As the illness progresses sufferers gradually lose their co-ordination and cognitive ability.