Abbreviated incubation times for human prions in mice expressing a chimeric mouse–human prion protein transgene

doi:10.1073/pnas.2627989100

Abbreviated incubation times for human prions in mice expressing a chimeric mouse–human prion protein transgene

^aInstitute for Neurodegenerative Diseases and Departments of ^kNeurology, ^mPathology, and ⁿBiochemistry and Biophysics, University of California, San Francisco, CA 94143; ^gDivision of Neuropathology, Case Western Reserve University, Cleveland, OH 44106; ⁱNational CJD Surveillance Unit, Western General Hospital, Edinburgh EX4 2HU, United Kingdom; and ^jNeuropathology Laboratory, University of Edinburgh, Edinburgh EH8 9LJ, United Kingdom

Contributed by Stanley B. Prusiner

Abstract

Transgenic (Tg) mouse lines that express chimeric mouse–human prion protein (PrP), designated MHu2M, are susceptible to prions from patients with sporadic Creutzfeldt–Jakob disease (sCJD). With the aim of decreasing the incubation time to fewer than 200 days, we constructed transgenes in which one or more of the nine human residues in MHu2M were changed to mouse. The construct with murine residues at positions 165 and 167 was expressed in Tg(MHu2M,M165V,E167Q) mice and resulted in shortening the incubation time to ≈110 days for prions from sCJD patients. The construct with a murine residue at position 96 resulted in lengthening the incubation time to more than 280 days for sCJD prions. When murine residues 96, 165, and 167 were expressed, the abbreviated incubation times for sCJD prions were abolished. Variant CJD prions showed prolonged incubation times between 300 and 700 days in Tg(MHu2M) mice on first passage and incubation times of ≈350 days in Tg(MHu2M,M165V,E167Q) mice. On second and third passages of variant CJD prions in Tg(MHu2M) mice, multiple strains of prions were detected based on incubation times and the sizes of the protease-resistant, deglycosylated PrP^Sc fragments. Our discovery of a previously undescribed chimeric transgene with abbreviated incubation times for sCJD prions should facilitate studies on the prion species barrier and human prion diversity.

Footnotes

↵ b Present address: Institut für Neuropathologie, Heinrich-Heine Universität Düsseldorf, Düsseldorf 40001, Germany.
↵ c Present address: National Center of Neurology and Psychiatry, and Core Research for Evolutional Science and Technology, Kodaira, Tokyo 187-8502, Japan.
↵ d Present address: Klinik für Neurochirurgie der Universität zu Köln, Cologne 50931, Germany.
↵ e Present address: Department of Microbiology and Immunology, University of Kentucky, Lexington, KY 40536.
↵ f Present address: Department of Neurology, University of Chicago, Chicago, IL 60637.
↵ h Present address: Department of Neurological Sciences, University of Bologna, Bologna 40123, Italy.
↵ l Present address: Neurochem, Inc., Ville St. Laurent, QC, Canada H4S 2A1.
↵ o To whom correspondence should be addressed. E-mail: stanley{at}itsa.ucsf.edu.
Abbreviations:

PrP,

prion protein;

PrPC,

normal cellular isoform;

PrPSc,

disease-associated isoform;

Tg,

transgenic;

CJD,

Creutzfeldt–Jakob disease;

vCJD,

variant CJD;

sCJD,

sporadic CJD