A Novel, Drug-based, Cellular Assay for the Activity of Neurotoxic Mutants of the Prion Protein |
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| Authors: | Tania Massignan Richard S Stewart Emiliano Biasini Isaac H Solomon Valentina Bonetto Roberto Chiesa and David A Harris |
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| Institution: | From the ‡Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri 63110 and ;the §Dulbecco Telethon Institute and ;the Departments of ¶Biochemistry and Molecular Pharmacology and ;‖Neuroscience, Istituto di Ricerche Farmacologiche “Mario Negri,” Via G. La Masa 19, 20156 Milan, Italy |
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| Abstract: | In prion diseases, the infectious isoform of the prion protein (PrPSc) may subvert a normal, physiological activity of the cellular isoform (PrPC). A deletion mutant of the prion protein (Δ105–125) that produces a neonatal lethal phenotype when expressed in transgenic mice provides a window into the normal function of PrPC and how it can be corrupted to produce neurotoxic effects. We report here the surprising and unexpected observation that cells expressing Δ105–125 PrP and related mutants are hypersensitive to the toxic effects of two classes of antibiotics (aminoglycosides and bleomycin analogues) that are commonly used for selection of stably transfected cell lines. This unusual phenomenon mimics several essential features of Δ105–125 PrP toxicity seen in transgenic mice, including rescue by co-expression of wild type PrP. Cells expressing Δ105–125 PrP are susceptible to drug toxicity within minutes, suggesting that the mutant protein enhances cellular accumulation of these cationic compounds. Our results establish a screenable cellular phenotype for the activity of neurotoxic forms of PrP, and they suggest possible mechanisms by which these molecules could produce their pathological effects in vivo. |
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| Keywords: | Prions Antibiotics Cell Death Drug Action Mutant Aminoglycoside Cell Assay Drug Mutant Neurotoxicity |
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