Selective incorporation of polyanionic molecules into hamster prions

James C. Geoghegan, Pablo A. Valdes, Nicholas R. Orem, Nathan R. Deleault, R. Anthony Williamson, Brent T. Harris, Surachai Supattapone

Research output: Contribution to journalArticlepeer-review

93 Scopus citations

Abstract

The central pathogenic event of prion disease is the conformational conversion of a host protein, PrPC, into a pathogenic isoform, PrPSc. We previously showed that the protein misfolding cyclic amplification (PMCA) technique can be used to form infectious prion molecules de novo from purified native PrPC molecules in an autocatalytic process requiring accessory polyanions (Deleault, N. R., Harris, B. T., Rees, J. R., and Supattapone, S. (2007) Proc. Natl. Acad. Sci. U. S. A. 104, 9741-9746). Here we investigated the molecular mechanism by which polyanionic molecules facilitate infectious prion formation in vitro. In a PMCA reaction lacking PrPSc template seed, synthetic poly(A) RNA molecules induce hamster (Ha)PrPC to adopt a protease-sensitive, detergent-insoluble conformation reactive against antibodies specific for PrPSc. During PMCA, labeled nucleic acids form nuclease-resistant complexes with HaPrP molecules. Strikingly, purified HaPrPC molecules subjected to PMCA selectively incorporate an ∼1-2.5-kb subset of [32P]poly(A) RNA molecules from a heterogeneous mixture ranging in size from ∼0.1 to >6 kb. Neuropathological analysis of scrapie-infected hamsters using the fluorescent dye acridine orange revealed that RNA molecules co-localize with large extracellular HaPrP aggregates. These findings suggest that polyanionic molecules such as RNA may become selectively incorporated into stable complexes with PrP molecules during the formation of native hamster prions.

Original languageEnglish (US)
Pages (from-to)36341-36353
Number of pages13
JournalJournal of Biological Chemistry
Volume282
Issue number50
DOIs
StatePublished - Dec 14 2007
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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