Figure 6.

Δ23–134 PrP is not toxic in a cell culture assay. HEK cells stably expressing the indicated constructs were treated for 48 h in the presence or absence of 400 μg/ml G418, after which cell viability was measured by MTT reduction. Cell viability is expressed as the value for MTT reduction (A₅₇₀) of G418-treated cells as a percentage of the value for untreated cells. The bars show mean values ± SEM. The asterisks indicate values that are significantly different from those for WT PrP (p < 0.0001).