NR AWKA
AU Medrano,A.; Biasini,E.; Barmada,S.J.; Harris,D.A.
TI GFP-tagged mutant prion protein forms aggregates in axons of transgenic mice
QU International Conference - Prion 2006: Strategies, advances and trends towards protection of society - 3.10.-6.10.2006, Torino, Italy, Lingotto Conference Centre - Poster sessions CE-30
PT Konferenz-Poster
AB Mutations in the prion protein (PrP) are associated with several familial prion diseases. Tg(PG14) mice express a mutant PrP (PG14) which contains an insertion encoding nine additional octapeptide repeats. These mice develop a neurological disorder characterized clinically by ataxia and neuropathologically by astrogliosis and PrP deposition. However, buried epitopes within PG14 PrP hinder effective antibody recognition of the protein in immunocytochemical experiments. To study PG14 PrP cellular distribution in vivo, we have generated transgenic mice expressing a PG14 PrP-EGFP fusion protein that allows direct visualization of the mutant PrP. Tg(PG14 PrP-EGFP) mice display clinical and neuropathological phenotypes similar to Tg(PG14) animals. Control mice expressing wild type PrP-EGFP (WT PrP-EGFP) remain asymptomatic. Biochemically, PG14 PrP-EGFP is distinct from WT PrP-EGFP, but similar to the infectious form of PrP (PrPsc), in that it is detergent insoluble, weakly protease resistant, and PIPLC resistant. In cerebellar granule cells cultured from transgenic mice, PG14 PrP-EGFP forms aggregates within neurites and shows decreased cell surface expression compared with WT PrP-EGFP. Confocal microscopy studies show that PG14 PrP-EGFP aggregation also occurs in vivo in neuropil regions throughout the brain. Aggregates are found at high densities in axon-dense regions, specifically in the hippocampus, striatum, and molecular layer of the cerebellum. These aggregates do not colocalize with markers for dendrites nor organelles in the cell soma, including the ER, Golgi apparatus, and lysosomes. In contrast, WT PrP-EGFP is uniformly distributed along the axonal cell surface and does not form aggregates. Axon-specific PG14 PrP-EGFP aggregation suggests that disruption of axonal transport systems may contribute to the disease phenotype. Further examination of PG14 PrP-EGFP trafficking in primary neurons will clarify what role axonal pathogenesis may play in the inherited prion disorder.
AD Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, USA
SP englisch
PO Italien