Fig. 4.
Effect of tacrolimus and astemizole on PrP transcription and translation. (A) Tacrolimus reduces both intracellular and cell membrane levels of PrPc, whereas astemizole has no effect on PrP levels at prion inhibitory doses (PID). PK1 cells were treated for 3 d with tacrolimus at 20 µM or astemizole at 2 µM, doses that prevented prion replication (Fig. 3). Cells were then cell surface biotinylated, and cell-surface and intracellular PrP were analyzed. Gel loading was standardized by cell number. The three blots represent three different exposure times of the same blot. (B) Tacrolimus and astemizole do not significantly alter PrP mRNA levels at PID. RT-PCR analysis of PrP mRNA levels in cells treated for 3 d with tacrolimus or astemizole at 20 and 2 µM, respectively. mRNA levels were standardized by using GAPDH mRNA.