Prions

Nobel Prize 1997Dr. Stanley Prusiner

“mad cow disease” “Scrapie”

Prions

What are prions?

What is the evidence for prions?

Notable prion diseases

Modes of obtaining “prion” diseases

Infectious pathogens resistant to:

Once the requirement of protein for infectivity was established, I thought that it was appropriate to give the infectious pathogen of scrapie a provisional name that would distinguish it from both viruses and viroids. After some contemplation, I suggested the term "prion," derived from proteinaceous and infectious (58). At that time, I defined prions as proteinaceous infectious particles that resist inactivation by

procedures that modify nucleic acids. I never imagined the irate

reaction of some scientists to the word "prion"   it was truly remarkable!

From: S. Prusiner, 1998: Nobel Laureate for Prions

Prion Diseases

Can have very long incubation periods

Present at approximately 50-60 years of age

Invariably fatal in a matter of months

Prions have been linked to various related neurological diseases

Kuru: human

Fatal Familial Insomnia: human

Creutzfeldt-Jakob disease (human)

Dr. Carleton Gajdusek

KuruNew Guinea

Brain tissue

Prion Diseases in Animals

Scrapie (goats, sheep)

BSE or Bovine Spongiform Encephalopathy (cattle)

Chronic Wasting Disease (deer, elk)

ScrapieBSE

KURU

Creutzfeld Jakob

Normal Mammalian Cells Have a: PrP gene

PrP protein Perhaps functions in cell communication

Prion diseases happen as a result of modified PrP

PrP http://gslc.genetics.utah.edu/features/prions/

The modified PrP forms “rods” and destroys nerve cells.

“Holes in the tissues are where the Nerve cells have been destroyed”.

Proteins that replicate

PrP Rod shape structures

Various strains of prions

Prion diseases may present as:

Genetic

Sporadic

Infectious

PrP

And many other manners of contactwith infected tissue.

Treatment

Currently no available treatment

Future drugs may target

Binding of modified PrP to wt Prp

Onto HIV/AIDS