Deleault et al., "Formation of native prions from minimal components in vitro," Proc Natl Acad Sci, 104: 9741-6, 2007. (Cited in 53 papers)
To test whether misfolded, disease-causing prion proteins could form from their normal counterparts without being seeded with the infectious form, biochemist Surachai Supattapone and his colleagues at Dartmouth Medical School in Hanover, NH, mixed a cocktail of purified, uninfectious prions, a synthetic, highly charged RNA, and some lipids. After stirring the concoction with sound waves, the normal proteins morphed into their lethal cousins and triggered scrapie—a fatal prion disease—when injected into hamsters.
The study was the first showing that fully infectious proteins can be created from scratch, "even without adding any infectious material in the reaction," says Ilia Baskakov, a biochemist at the University of Maryland Biotechnology Institute in Baltimore. "It's one of the milestones in the field."
In 2007, Supattapone's team used fluorescent labeling to show that the highly charged RNA molecule physically incorporates into the misfolded, infectious prion after the sonic treatment (J Biol Chem 82:36341-53, 2007).
The next step:
Supattapone's team is now working to discover the naturally occurring cofactors that make the good proteins go bad. "If we can remove the cofactor molecule from the infectious agent," he says, "how will that affect the infectivity of the final product?"
|Cocktail||Hamsters with scrapie||Mean time until symptoms|
|Normal protein alone (PrPC)||0/5||>370 days|
|RNA + PrPC without amplification||0/6||>360 days|
|RNA + PrPC with amplification||7/8||134 days|