Developmental regulation of prion protein mRNA in brain.

During development of the hamster brain, synthesis of the cellular isoform of the scrapie prion protein (PrPC) was found to be regulated. Low levels of PrP poly(A)+ mRNA were detectable one day after birth. PrP poly(A)+ mRNA reached maximal levels between 10 and 20 days post-partum; thereafter, no change in its level could be detected at ages up to 13 months. In contrast, myelin basic protein poly(A)+ mRNA was shown to reach maximal levels by 30 days of age and thereafter steadily declined in adult brain. Using monospecific PrP antisera, immunoprecipitable cell-free translation products were detected at low levels two days after birth and progressively increased up to 10 days of age. How the PrP mRNA participates in brain development and its function in scrapie prion infection are being investigated.