Prion diseases (e.g. Mad Cow disease) are caused by infectious conformations of the prion protein (PrP). These abnormal conformations (termed PrPSc) are capable of recruiting normal PrP molecules (termed PrPC), and converting them into PrPSc. The advent of synthetic prions, which are formed from recombinant prion protein (recPrP) folded into beta sheet-rich conformations, is enabling new insights into the structural basis of prion infectivity (Legname, et al., Science, 2004). Recent evidence suggests that the conformational stability of prions isolated from infected mice correlates directly with the incubation period for the onset of CNS dysfunction (Legname, et al., manuscript in preparation). Our work seeks to establish whether it is possible to generate misfolded PrP conformers with varying conformational stabilities in vitro, and if so, whether these conformers result in different incubation periods upon intracerebral injection into mice. We have identified conditions for the formation of recPrP conformers that are less stable, or less resistant to guanidine and temperature denaturation. Differences in fiber morphology were observed by electron microscopy and AFM. Whether these differences will correspond to changes in the incubation period remains to be determined. The ability to create distinct conformations of PrP in vitro and to correlate their structural features to prion disease pathology will be of enormous value to understanding the structural basis of prion infectivity.

Extended Abstract Status: Not Uploaded