- Researchers have figured out how to build their own artificial
prions, the deadly, malformed proteins that cause the brain decay of mad-cow
disease as well as Creutzfeldt-Jakob, the human form of the disease.
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- Why would anyone want to build something so destructive?
Because by making their own prions, researchers can learn how they work.
Learning how these deadly proteins operate is the first step in understanding
how to stop their destruction.
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- University of California at San Francisco researchers
built prions using yeast cells, so the value of their work hinges on the
assumption that mammalian prions will behave like the ones made from yeast
cells. If they do, researchers can use the artificial prions to test treatments
for mad cow and the various versions of Creutzfeldt-Jakob disease.
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- "One can treat the 'infected' yeast cell with different
chemical compounds to see if the artificial prion is cured," said
Chih-Yen King, a prion researcher at Florida State University who critiqued
the UCSF research, which is published in the April issue of the Public
Library of Science Biology journal. "The effective lead compounds
could potentially be developed into drugs to treat human (prion) diseases."
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- Since Stanley Prusiner discovered prions in 1982, researchers
have learned little about how they work. Prions pass on their brain-killing
traits to other proteins in a way researchers previously thought only DNA
could do. When one prion morphs, it causes similar proteins nearby to also
morph. As a group, these jagged masses of cells cut holes in the brain,
in an endless cycle that's always fatal.
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- Researchers thought perhaps one day someone would discover
that DNA actually plays a role in the process. But last week, two studies
by King and others, published in the March 18 issue of Nature, provided
evidence that proteins were, in fact, acting on their own to become destructive
prions and instigate other proteins to become prions.
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- The UCSF work published in PLoS Biology reinforced that
finding.
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- "They are able to show how prions can begin to cause
misfolding amongst the proteins, but more importantly, how they can pass
this trait on to their daughter cells," said Philip Bernstein, the
senior editor at PLoS Biology who worked on the UCSF research.
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- Beyond that, the UCSF researchers built their own prions
from yeast cells.
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- "Understanding this simple model may help us provide
an entree into understanding more complex mammalian disease," Bernstein
said.
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- Humans who eat meat from cows infected with mad-cow disease
can get variant Creutzfeldt-Jakob disease. It has killed 153 people, almost
all in Britain, since it was discovered in 1995. The disease has an extraordinarily
long incubation period: While the mad-cow epidemic (during which 36 million
cows were infected) struck the United Kingdom in the late 1980s, the first
cases of CJD didn't emerge until the mid-1990s.
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- Members of a New Guinea tribe of cannibals have been
infected with another version of the disease, called kuru. Yet another
type of prion disease -- known as sporadic Creutzfeldt-Jakob disease --
seems to emerge in people whether they've eaten infected meat or not. It's
always fatal and strikes about 200 Americans every year.
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- © Copyright 2004, Lycos, Inc. All Rights Reserved.
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- http://www.wired.com/news/medtech/0,1286,62781,00.html?tw=wn_tophead_4
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