( r. Surewicz says the next step in th...)Fibril Shape Is The Basis Of Prion Strains And Cross-species Prion Infection

Surewicz says the next step in their research will be to examine fibril shape differences at much higher resolution. Their experiments also used a shortened version of the mammalian prion protein, so they hope to test the fibril factor in a full-length protein soon.

Jones and Surewicz also note that the new findings offer "the unsettling possibility" that repeated cross-species transmission events might eventually create prion fibril strains that can bridge the infection gap between previously separate animals like humans and elk and deer, which suffer from a prion disease called chronic wasting disease.

Surewicz stresses, however, prion infection between species is still rare. "Fortunately, transmission by eating is very ineffective. There have been hundreds of thousands of bovine spongiform encephalopathy cases, for example, and lots of people exposed to tainted beef products, but very few cases of variant Creutzfeld-Jakob."

He says there "must be protective mechanisms working there, but we don't know what they are."

The other members of the Weissman research team include Motomasa Tanaka and Peter Chien. The Weissman study was supported by Howard Hughes Medical Institute, The David and Lucile Packard Foundation, and the National Institutes of Health. The Jones and Surewicz study was supported by the National Institutes of Health.

Eric M. Jones and Witold K. Surewicz: "Fibril Conformation as the Basis of Species-and Strain-Dependent Seeding Specificity of Mammalian Prion Amyloids"

Motomasa Tanaka, Peter Chien, Koji Yonekura, and Jonathan S. Weissman: "Mechanism of Crossspecies Prion Transmission: An Infectious Conformation Compatible with Two Highly Divergent Yeast Prion Proteins"

Publishing in Cell, Volume 121, Number 1, April 8, 2005. http:/?​www.cell.com