prions study and their description

1. Government college University of Faisalabad
Department of bio- informatics
By: Khansa Asad
Prions

2. Introduction:
The term PRION is derived from proteinacioues infectious particle and refer to the pathogen that
cause "Transmissible spongiform encephalopathies"(TsFs). A prion is a type of protein that can
trigger normal proteins in the brain to fold abnormally. Prion diseases can affect both humans
and animals and are sometimes spread to humans by infected meat products. The most common
form of prion disease that affects humans is Creutzfeldt-Jakob disease (CJD)
Discovery:
PRION is a infectious disease.
Prion recently discovered by American Neurobiologist"STANLEY Prusiner".
Prion is the least understood Micro organism
Nature:
Nature of PRION is CONTROVERSIAL.
Composed of:
Prion is composed of protein only that contains the information and codes for their own
replication.
Responsibility:
responsible for the mad cow infection.
for the my mysterious brain infection in man
Function:
The physiological function of PRION protein remains a CoNTROVERSIAL matter.
While data from in vitro experiment suggests may dissimilar roles,studies on PrP knockout mice
have provided only limited information because these Animals exhibit only minor
abnormalities.The research done in mice it was found that the cleavage of PrP protein in
peripheral nerves causes the Activation of myelin repair in Sechwan Cells and that the Lack of
PrP protein caused Demyelination in these cells. Prions are misfolded proteins with
the ability to transmit their misfolded shape onto normal variants of the same protein. They
characterize several fatal and transmissible neurodegenerative diseases in humans and many
other animals.

3. Prion replication mechanisms:
The firsthypothesisthattriedtoexplainhow prionsreplicate inaproteinonlymannerwasthe
HeterodimerModel.
Thismodel assumedthata single PrPscmolecule bindstoasingle PrPcmolecule andCatalyzesit's
conversion intoPrPsc.The twoPrPscmoleculethencome apartandcan go onto convertmore PrPc.

4. Manfredeigenshowthatthe heterodimermodel requiresPrPsctobe an extraordinaryeffective
Catalyzes,increasingthe rate of conversionreactionbyafactor of around 10(15).
The mechanismsof PRION replicationhasimplicationsof designingdrugs.

5. Structure:
The protein that prions are made Of PRION protein(prp) is found Throughout the body,even in
healthy People and in animals. However,PrP found in infectious material has a Different
structures and is resistance to Proteases ,the enzymes in the body that can normallyBreakdown
protein.The Normal from of protein is called PrPc.While infectious from is called PrPsc.
The' C' refers to cellular and while the'Sc'Refers to" scrapie"
Won prize:
Prusiner won the" Nobel prize" of Physiology or medicine in 1997 for his researchers into prions.
PRION diseases and their transmission:
AffectedAnimals(s): Diseases:
Sheepor
Goat:-
causes the:
"SCRAPIE"
Cattle:- Bovine spongiformencephalopathies
(BSE)-"madcow" diseases
Mink:- Transmissible mink,encephalopathy
(TME).
White-taileddeer,mule,elk,
Deer,moose:-
ChrONICWASTING
Diseases(CWD).
Cat:- Feline spongiformencephalopathy
(FSE).

6. Nyala,OryX,
Greaterkudu:-
These animals are also effected
By prions as Exoticungulated
Encephalopathy(EUE).
Ostrich:- Spongiformencephalopathy
(Has not beenshown to be transmissible)
Humans:-
-Creutzfeld-jakobdiseases(CJD).
-variant creutzfeld-jakobdisease(VcJD)
-latrogeniccreutzfeld-jakobdisease(ICJD).
-familial creutzfeld-jakobdisease(fcJD).
-sporadic-straussler-schienkersyndrome(Gss).
-fatel familial insomnia(FFI).
-Familial spongiformencephalopathy
-Multiple systemAtrophy(MSA)
Not a TSE and isnot by typical prions
PrP/PrPsc,but by a misfoldedas
Alpha-synuclein.
PrP and long-term memory:-
A review of the evidence in 2005 suggests ,That PrP may have a normal function In maintenance
of "LonG-Term Memory" As well a,2004 study found thatMice lacking genes for normal
Cellular PrP protein show altered Hippocampal lonG-term potentiation.

7. Types:-
1-PrPc
2-PrPsc
The Normal from of protein is called the PrPc.
While the infectious protein from is called the PrPsc.