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Flashcards in Prions Deck (14)
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1
Q

What is the definition of prions?

A

Small, proteinaceous infectious particle that resists inactivation by procedures that modify nucleic acids

2
Q

What is the mechanism by which prions work?

A
Mutant protein (PrPsc) has same amino acid as normal protein (PrPc), just different folding
Mutant can make normal protein change folding to become mutant structure
3
Q

What is the disease caused by prions?

A

Transmissible spongiform encephalopathy

4
Q

What are clinical presentations of spongiform encephalopathy?

A

Loss of motor control, dementia, paralysis wasting and eventually death, typically following pneumonia

5
Q

What animal is infected with Scrapie?

A

Sheep

6
Q

What are histological characteristics of spongiform encephalopathies on autopsy?

A

Vacuoles in cerebellum and cortex
Amyloid deposits
Astrocytosis
Can also stain for prions now

7
Q

What diseases are in the category of inherited TSEs?

A

Familial Creutzfeldt-Jacob Disease (CJD)
GSS
Fatal Familial Insomnia (FFI)

8
Q

What diseases are in the category of spontaneous TSEs?

A

Spontaneous Creutzfeldt-Jacob Disease

Fatal Sporadic Insomnia (FSI)

9
Q

What diseases are in the category of infectious TSEs?

A

Kuru (ritualistic cannibalism)

New Variant CJD (nvCJD; from bovine prions)

10
Q

What is the name of the normal form and of mutant form of the prion protein?

A

PrPc - normal

PrPsc - mutant

11
Q

What are the two proposed models of prion propagation?

A

Refolding model - conversion between PrPc and PrPsc prevented, requires induction
Seeding model - equilibrium between PrPc and PrPsc, seed formation of more PrPsc

12
Q

Which is more efficient, prion infection in same species or different species?

A

Same species

13
Q

How are prion disease transmitted?

A

Acquired (infectious): diet, medical procedures involving contaminated instruments, growth hormone injections, transplants
Inherited: mutated PrPc better allow conversion to PrPsc
Spontaneous: PrPc -> PrPsc

14
Q

When are prions beneficial?

A

In yeast - allows switch between phenotypic states and better survive stressful environment (increased fitness)