DESCRIPTION OF VIRUSES

Prions

Table Gallery

Table Gallery

Table 1 The prion diseases

Disease (abbreviation)

Natural host

Prion

Pathogenic PrP Isoforms

Scrapie

sheep & goats

Scrapie prion

OvPrPSc

Transmissible mink encephalopathy (TME)

mink

TME prion

MkPrPSc

Chronic wasting disease (CWD)

mule deer & elk

CWD prion

MDePrPSc

Bovine spongiform encephalopathy (BSE)

cattle

BSE prion

BoPrPSc

Feline spongiform encephalopathy (FSE)

cats

FSE prion

FePrPSc

Exotic ungulate encephalopathy (EUE)

nyala & greater kudu

EUE prion

UngPrPSc

Kuru

humans

Kuru prion

HuPrPSc

Creutzfeldt-Jakob disease (CJD)

humans

CJD prion

HuPrPSc

Gerstmann-Sträussler Sheinker syndrome (GSS)

humans

GSS prion

HuPrPSc

Fatal familial insomnia (FF1)

humans

FF1 prion

HuPrPSc

Table 2 Glossary of prion terminology

Term

Description

Prion

A proteinaceous infectious particle that lacks nucleic acid. Prions are composed largely, if not entirely, of PrPSc molecules.

PrPSc

Abnormal, pathogenic isoform of the prion protein that causes sickness. This protein is the only identifiable macromolecule in purified preparations of prions.

PrPC

Cellular isoform of the prion protein.

PrP 27-30

Digestion of PrPSc with proteinase K generates PrP 27-30 by hydrolysis of the N-terminus

PRNP

Human PrP gene located on chromosome 20.

Prnp

Mouse PrP gene located on syntenic chromosome 2. Prnp controls the length of the prion incubation time and is congruent with the incubation time genes Sinc and Prn-i. PrP-deficient (Prnp°/°) mice are resistant to prions.

PrP amyloid

Fibril of PrP fragments derived from PrpSc by proteolysis. Plaques containing PrP amyloid are found in the brains of some mammals with prion disease.

Prion rod

An amyloid polymer composed of Prp 27-30 molecules. Created by detergent extraction and limited proteolysis of PrPSc.

Protein X

A hypothetical macromolecule that is thought to act like a molecular chaperone in facilitating the conversion of PrPC into PrPSc.

Table 3 Examples of human PrP gene mutations found in the inherited prion diseases

Inherited prion disease

PrP gene mutation


Gerstinann-Straussler-Scheinker disease

PrP P1O2L*

Gerstmann-Straussler-Scheinker disease

PrP AI17V

Familial Creutzfeldt-Jakob disease

PrP D178N, V129

Fatal familial insomnia

PrP D178N, M129*

Gerstmann-Straussler-Scheinker disease

PrP F198S*

Familial Creutzfeldt-Jakob disease

PrP E2OOK*

Gerstmann-Straussler-Scheinker disease

PrP Q217R

Familial Creutzfeldt-Jakob disease

PrP octarepeat insert*

*; signifies genetic linkage between the mutation and the inherited prion disease.