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Hello, my name is Claudio Soto,
I'm Professor and Director of
the Mitchell Center for Neurodegenerative
Diseases at the Department of Neurology,
University of Texas Medical Branch.
I'll be talking today about the use of the
cyclic amplification of protein misfolding
for the generation and
propagation of infectious prions.
One of the unique characteristic of prion
diseases is that the prion protein can
exist in two different stages.
One is the normal prion protein that
we call PrPc, 'c' stands for cellular.
And this is a protein that we all have,
all healthy people or animals have.
The protein has a biological function,
sensitive to proteolysis and soluble.
However, the same protein with the same
sequence is also found in sick people or
animals with a different folding.
This is the so-called abnormal prion
protein, and we call it PrPSc.
This protein is supposed to be toxic and
infectious, is rich in beta-sheet
conformation, is resistant to proteolysis,
and is insoluble.
The infectious agent
associated to prion diseases,
is supposed to be composed exclusively by
the misfolded form of the prion protein,
PrPSc, here in the figure
represented in red squares.
The way that the misfolded prion
protein propagates a disease is by
transforming the normal
version of the protein PrPc,
represented in the figure in green
circles, gradually into its own.
Gradually from the normal form into
the misfolded form in a relatively slow
process to get to the point
in which sufficient amount
of the normal protein has been
transformed into the misfolded form, and
this will produce tissue damage and
The period between the infection time
to the time in which animals develop
the disease is called incubation time,
and this variable depends on the species.
For example, in rodents this
period can take several months,
in cattle, for example,
it can take several years, and
in the case of humans it
can take several decades.