Stable expression of WT-PrP, Met4-1-PrP, or ΔN6-PrP in RK13 cells.A, DAPI and immunofluorescence staining of stably transfected RK13 cells with the 3F10 anti-PrP antibody. N2a cells were used as the positive control, and untransfected RK13 cells were used as the negative control. Densitometric analysis of relative fluorescence intensity of 3F10 anti-PrP antibody-stained WT and mutant PrP proteins (n = 3, right panel). The relative fluorescence intensity of WT was set as 1.0. The scale bar represents 100 μm. B, Western blotting of RK13-WT, RK13-Met4-1, and RK13-ΔN6 cell lysates with 3F10 anti-PrP antibody (left panel) and densitometric analysis (right panel, n = 3). The average intensity of 3F10 antibody-stained bands of RK13-WT cells was set as 1.0. C, undigested (left panel) and PNGase-digested (right panel) RK13-WT, RK13-Met4-1, and RK13-ΔN6 cell lysates were examined by Western blots. Statistical significance was determined by one-way ANOVA followed by Tukey's multiple comparison test. ns represents no statistically significant difference. Error bars indicate standard deviations. DAPI, 4′,6-diamidino-2-phenylindole; PrP, prion protein.