Inducible expression of chimpanzee prion protein (PrP) in murine PrP knock-out cells

Abstract In transmissible spongiform encephalopathy (TSE) pathogenesis the cellular prion protein (PrP C ) is converted into its pathogenic PrP Sc isoform. Prion protein gene ( Prnp ) deficient mice (PrP 0/0 ) are resistant to PrP Sc infection, but following reconstitution of Prnp they regain their susceptibility to infection. Therefore, it is challenging to simulate this natural situation in a cell culture model. We have previously reported the inducible stable expression of a human PrP C in murine 3T3 cells. In this study, we used murine PrP 0/0 cells stably expressing exemplarily the chimpanzee Prnp under the control of inducible tetracycline (Tet) system. The Prnp was integrated using a lentiviral vector. Its expression in the engineered PrP 0/0 Chimp1/Tet-Off cell line was analyzed by Western blot (Wb) and fluorescence activated cell sorting (FACS) analyses. PrP C was partially purified by using immobilized metal affinity chromatography (IMAC). Compared to all the other cell systems which possess an endogenous PrP C expression, here described cell line contains only an overexpressing species specific PrP C expression which is tightly regulated and can be turned-off at any time without showing any endogenous host PrP C expression. Consequently, a contamination of the isolated PrP C is impossible. This cell line potentially offers a new tool for simulation of mice bioassays widely used in TSE infection studies.