Chapter Nine - Transmission and Replication of Prions
Section snippets
The “Protein-Only” Hypothesis
The longest known transmissible spongiform encephalopathy (TSE), scrapie, was first thought to be a muscle disease caused by parasites1 or by “filterable” virus of slow progression.2 Soon, however, there was more and more evidence to suggest that the scrapie agent was something different from a virus. It was noted to be resistant to treatments that destroy nucleic acids2, 3 but susceptible to treatments that disrupt protein structure.4, 5, 6, 7, 8 In parallel, attempts to identify a
Prion Transmissibility and the Species Barrier
One of the main characteristics that differentiates TSEs from other neurodegenerative diseases caused by protein misfolding and aggregation is their transmissibility among individuals of the same species and other species. Transmission between different species is an especially worrying characteristic since a given prion disease could “jump” from its natural host to other species including humans.
Fortunately, because of the so-called species barrier, interspecies transmission is not so
Concluding Remarks
Advances in the study of prion transmission and replication have paralleled the development of appropriate tools and technologies shedding some light on the still obscure pieces of the complicated puzzle of TSEs.
The molecular mechanisms of prion replication have not been clearly defined. Neither is it known how strain information is maintained and transmitted or which mechanisms define the tropisms of prion strains. Resolving these issues may also significantly impact other protein misfolding
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