Figure 6. Expression of PrP in PSP and FTLD (fFTLD-tau and FTLD-TDP-43) frontal cortex. (A) mRNA average expression levels of PrP in the frontal cortex in control (Con), PSP and FTLD cases determined by TaqMan PCR assays. Values for PrP mRNA are normalized using GUSβ and XPNPEP1 as internal controls. (B) western blot analysis of PrP in the frontal cortex of control (Con), PSP and FTLD cases in five representative cases per condition; β-actin is used to normalize total protein loading. Densiometric values of all the cases analyzed by western blot: control (n = 7), PSP (n = 12) and FTLD (n = 7) show reduced PrP expression in PSP and FTLD. *P > 0.05; **P > 0.01; ***P > 0.001: control vs PSP/FTLD cases. (C) PK digestion of PSP and FTLD samples confirm that PSP and FTLD do not contain PrPsc.