Prion

Question 1

what are prion diseases

Answer 1

a collection of neurodegenrative diseases that are mainly from an infectious protein agent that causes conformational change and results in extensive brain damage

Question 2

what are the four main types of PR D

Answer 2

1. sporadic
   - most common
   - CJD
2. inherited
   - mimics famial AD
   - CJD, GSS, insomnia
3. acquired
   - medical procedures or surgeries
   - cannabillism -leading to Kuru
4. environmental
   - blood tranfusions
   - variant CJD

Question 3

what are the differences between virus and viriods

Answer 3

Virus

• can be made up of RNA or DNA
• have nucleic acids, sometimes envelope, protein coat
• replicates in a living host

Viroids

• smaller than virus
• only made up of RNA
• infectious particle that can cause disease

Question 4

what are Prions

Answer 4

• infectious protein particle
• similar to virus but has NO nucleic acid
• pathogenic
• transmissble
• non degradable
• induces abnormal folding in prion proteins which are mostly found in the brain

Question 5

differences between PRPsc and PRPc

Answer 5

PRPc “sen” cellular

• normal
• transmembrane glycoproteins (neurons, lympocytes)
• secondary structure usually alpha helix
• monomeric so its easily degraded by protease
• easily soluble
• binds to copper

PRPsc “res” scrapie

• abnormal
• multimeric so resitant to protease
• causes abnormal folding
• converts PRPc to PRPsc
• secondary structure usually beta sheets
• insolbule
• binds to form aggregates

Question 6

what is TSE

Answer 6

transmissible spongiform encephalopathies

- after prion disease the brain become sponge like

Question 7

brain areas affected:
CJD: \_\_\_\_\_ \_\_\_\_\_
Fatal insomnia: \_\_\_\_\_\_\_
Kuru: \_\_\_\_\_\_\_\_
scrapie, BSE, chronic wasting disease: \_\_\_\_\_ \_\_\_\_

Answer 7

cerebral cortex
thalamus
cerebellum
brain stem

Question 8

what are 3 main hallmarks of ND?

Answer 8

• protein accumulation
• protein aggregation
• misfolding
  which lead to neuronal loss, synaptic connectivity loss, cellular dysfunction, brain damage

Question 9

what is the Prion Only Hypothesis

Answer 9

sole component of infectious agent in TSEs is a misfolded version of the prion protein (PRPsc) which replicates by converting PRPc